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Transcript
Slovenská elektrizačná prenosová sústava, a.s. Bratislava SLOVAK TRANSMISSION SYSTEM CODE September 2002 OFFICE FOR REGULATION OF NETWORK INDUSTRIES Bajkalská 27, 821 01 Bratislava Slovenská elektrizačná prenosová sústava, a.s. Miletičova 5 82484 Bratislava Bratislava, 21.8.2002 No: 1904/ÚRSO/02/09 Re Transmission System Code - approval The Office for Regulation of Network Industries (hereinafter referred to as the "Office") following detailed review and assessment in terms of the provisions of Act No. 276/2001 Coll. on regulation of network industries and on alteration and amendment to certain laws, as altered and amended, as well as in terms of the provisions of Act No. 70/1998 Coll. on power engineering and on alteration to Act No. 455/1991 Coll. on trade business (Trade Act), as altered and amended, hereby approves the Transmission System Code the draft of which has been submitted to the Office by Slovenská elektrizačná prenosová sústava, a.s., Bratislava and which is to take effect 1 September 2002. It at the same time requests the Office that Slovenská elektrizačná a prenosová sústava, a.s., Bratislava discuss with it ahead and approve any possible changes thereto. The Transmission System Code in question is published on Slovenská elektrizačná prenosová sústava, a.s., Bratislava´s web side (www.sepsas.sk). Ing. Peter Čarakčiev Chairman 2 TABLE OF CONTENTS TABLE OF CONTENTS ..................................................................................................................................... 3 LIST OF TABLES ............................................................................................................................................... 6 LIST OF PICTURES .......................................................................................................................................... 6 LIST OF USED ABBREVIATIONS AND DESIGNATIONS ............................................................................... 7 INTRODUCTION ............................................................................................................................................... 8 1 2 GENERAL PROVISIONS ........................................................................................................................... 9 1.1 Transmission system ......................................................................................................................... 10 1.2 Transmission system operator .......................................................................................................... 10 1.3 Transmission system users ............................................................................................................... 10 1.4 Transmission system operator responsibilities ................................................................................. 11 1.5 Basic tasks of the transmission system ............................................................................................. 11 1.5.1 Transmission services ................................................................................................................ 11 1.5.2 System services ......................................................................................................................... 12 1.5.3 Support services......................................................................................................................... 12 CONDITIONS FOR CONNECTION TO THE TRANSMISSION SYSTEM .............................................. 13 2.1 Objectives of the connection rules .................................................................................................... 13 2.1.1 2.2 General conditions ..................................................................................................................... 13 Technical conditions for connection of consumers ........................................................................... 14 2.2.1 Active energy take-off ................................................................................................................ 14 2.2.2 Reactive energy take-off ............................................................................................................ 15 2.2.3 Consumer´s influence on voltage quality ................................................................................... 15 2.2.4 Other requirements for data from consumers ............................................................................ 15 2.3 Conditions for connection of production units ................................................................................... 16 2.3.1 Data from production units ......................................................................................................... 16 2.4 Technical conditions for transit .......................................................................................................... 17 2.5 Technical conditions for real-time control .......................................................................................... 18 2.5.1 Dispatching measurement and signalling .................................................................................. 18 2.5.2 Instrumentation and measuring equipment ................................................................................ 18 2.5.3 Real-time control data transmission ........................................................................................... 19 2.6 Power system equipment protections ............................................................................................... 19 2.6.1 Technical conditions for protection between the production unit and the transmission system .................................................................................................................................................... 20 2.6.2 Technical conditions for protection between consumers and the transmission system.......... ............................................................................................................................................ 21 2.7 3 Provisions for setting up commercial measurement ........................................................................ 22 2.7.1 Technical conditions for measurement ...................................................................................... 22 2.7.2 Electricity measurement ............................................................................................................. 23 AUTOMATIC SUPERVISORY CONTROL SYSTEM ............................................................................... 25 3.1 Technical requirements and backup ................................................................................................. 25 3.2 Control and information systems of electric stations ....................................................................... 25 3.2.1 4 Technical requirements .............................................................................................................. 26 3.3 Control and information systems of production units ....................................................................... 26 3.4 Precautions in data exchange ........................................................................................................... 26 OPERATION AND DEVELOPMENT OF THE TRANSMISSION SYSTEM ............................................. 28 3 4.1 Planning repairs and maintenance .................................................................................................... 28 4.2 Performance of maintenance ............................................................................................................. 28 4.3 Nature of inputs for planning the transmission system development ................................................ 29 4.3.1 Underlying documents for planning the transmission system development .............................. 30 4.3.2 Links between the transmission system and users .................................................................... 30 4.3.3 Data for transmission system development studies ................................................................... 31 4.3.4 Public information ....................................................................................................................... 31 4.4 5 Security and quality of operation of the transmission system ............................................................ 32 4.4.1 Failure spread defence plan and system recovery ..................................................................... 32 4.4.2 Failure spread defence plan ....................................................................................................... 33 4.4.3 System recovery plan ................................................................................................................. 35 MANAGEMENT OF THE POWER SYSTEM ............................................................................................ 37 5.1 System services ................................................................................................................................. 37 5.1.1 Primary power control ................................................................................................................. 37 5.1.2 Secondary control of frequency and powers to be exchanged .................................................. 38 5.1.3 Tertiary power control ................................................................................................................. 39 5.1.4 Dispatching reserve .................................................................................................................... 40 5.1.5 5.1.6 5.1.7 Control of voltage and reactive powers ...................................................................................... 40 Stability of the power system..................................................................................................... 40 Operation recovery following system disintegration ................................................................... 41 5.2 Source operation planning and co-ordination .................................................................................... 42 5.2.1 Stages for developing plans ....................................................................................................... 42 5.2.2 Study on the Slovak Power System operation for the year n+1 ................................................. 42 5.2.3 Monthly plan................................................................................................................................ 45 5.2.4 Weekly plan ................................................................................................................................ 47 5.2.5 Daily plan .................................................................................................................................... 47 5.3 Planning and co-ordination of operation of the transmission system .................................................... 48 5.3.1 Annual preparation for operation of the transmission system ........................................................ 48 5.3.2 Monthly preparation for operation of the transmission system ...................................................... 51 5.3.3 Weekly preparation for operation of the transmission system ....................................................... 52 5.3.4 Daily preparation for operation of the transmission system ........................................................... 52 5.4 6 Consumption control .......................................................................................................................... 53 REQUIREMENTS FOR SOURCES .......................................................................................................... 54 6.1 General requirements for generating units ........................................................................................ 54 6.1.1 Special requirements for units .................................................................................................... 54 6.1.2 Self consumption ........................................................................................................................ 55 6.1.3 Recovery plan requirements ....................................................................................................... 55 6.2 Support services ................................................................................................................................ 55 6.3 Active power regulation ...................................................................................................................... 56 6.3.1 Breakdown of unit active power .................................................................................................. 56 6.3.2 Requirements for primary active power regulation ..................................................................... 57 6.3.3 Requirements for secondary active power regulation ................................................................ 57 6.3.4 Requirements for tertiary active power regulation ...................................................................... 57 6.3.5 Requirements for active power reserve ...................................................................................... 58 6.4 Voltage regulation .............................................................................................................................. 58 4 7 6.4.1 Requirements for primary voltage regulation ............................................................................. 58 6.4.2 Requirements for secondary voltage regulation ........................................................................ 58 6.5 Methodologies for verification of support services ............................................................................ 59 6.6 Requirements for protections and automatics ................................................................................... 59 6.6.1 Requirements for electric equipment protections ...................................................................... 59 6.6.2 Requirements for automatics ..................................................................................................... 60 6.6.3 Basic requirements for unit management systems .................................................................... 60 information collection and handover ......................................................................................................... 61 7.1 7.1.1 Information from power plants .................................................................................................... 61 7.1.2 Information from foreign transmission systems ......................................................................... 62 7.1.3 Information from the distribution system .................................................................................... 62 7.1.4 Information on development of the transmission system and sources ...................................... 63 7.1.5 Information from the transmission system ................................................................................. 63 7.1.6 Information and documents prepared by the transmission system operator dispatching centre .................................................................................................................................................... 63 7.2 Failure information ............................................................................................................................. 65 7.3 On-line measurement and signalling ................................................................................................. 66 7.3.1 On-line measurement and signalling from the transmission system ......................................... 66 7.3.2 On-line measurement and signalling from foreign transmission systems.................................. 66 7.3.3 On-line measurement and signalling from the distribution system ............................................ 67 7.3.4 On-line measurement and signalling from power plants ............................................................ 67 7.4 Requirements for quality of process data and the method of information exchange ........................ 68 7.4.1 Process data quality ................................................................................................................... 68 7.4.2 Precautions in data exchange .................................................................................................... 68 7.4.3 Compatibility and requirements for transmission paths ............................................................. 69 7.4.4 Data transmission....................................................................................................................... 69 7.4.5 Accuracy and cycle of measurement for secondary active power regulation ............................ 69 7.5 Documentation .................................................................................................................................. 69 7.5.1 Operation preparation ................................................................................................................ 69 7.5.2 Operative operation .................................................................................................................... 69 7.5.3 Operation analysis...................................................................................................................... 70 7.6 8 Operating information ........................................................................................................................ 61 Background papers for grid calculations ........................................................................................... 70 7.6.1 Factors of the transmission system ............................................................................................ 70 7.6.2 Factors of foreign transmission systems .................................................................................... 70 7.6.3 Factors of distribution systems ................................................................................................... 70 7.6.4 Consumption values ................................................................................................................... 70 7.6.5 Source parameters ..................................................................................................................... 70 7.6.6 Transits ....................................................................................................................................... 71 Requirements for telecommunications for power system control ............................................................ 72 8.1 Scope of application .......................................................................................................................... 72 8.2 Operation and maintenance of the telecommunication system ........................................................ 73 8.3 TSO concurrence with other organizations ....................................................................................... 73 8.4 Quality requirements ......................................................................................................................... 74 8.5 Safety requirements .......................................................................................................................... 74 5 Final provisions ................................................................................................................................................. 75 Annex 3. Related legislation ...................................................................................................................... 76 Quality of electricity supplied from the transmission system ...................................................... 78 Instrumentation requirements..................................................................................................... 79 Annex 4. Frequency plan .......................................................................................................................... 81 Annex 5. Glossary ..................................................................................................................................... 83 Annex 1. Annex 2. LIST OF TABLES Table 6.1 Start times for new thermal units ............................................................................................ ........54 Table 6.2 Required changes in power for new installations ........................................................................... 54 Table 6.3 List of electric equipment protections…..................................................................... .................... 61 LIST OF PICTURES Fig. 6.1 Division of unit active power ........................................................................................................... 57 6 LIST OF USED ABBREVIATIONS AND DESIGNATIONS ASCS ACS ATC AC ADL CPP CC CIS CET CPS CENTREL D – SE DLC DS DR DST EMC EU hf HPP IVT ICT LAN NTC NTF OI PS PDH PSS PSP RS SPC SLDC SR SE STN SHPP SVC SVCo SPP SSE SDH SFA TPR TCS TTC TS TSO TRM UCTE VED VET VSE ZSE WAN Automatic Supervisory Control System Automated Control System Available Transmission Capacity Available Capacity Annual Diagnostic Load Captive Power Plant Combined Cycle Control Information System Central European Time Countinuous Power Supply TSO Regional Group for the Co-ordination of the Slovak, Czech, Hungarian, Polish Power Systems SE, a.s., Generation and Trade Dispatching Centre Daily Load Curve Distribution System Dispatching Reserve Daylight Saving Time Electromagnetic Capacity European Union High-Frequency Hydroelectric Power Plant Instrument Voltage Transformer Instrument Current Transformer Local Area Network Net Transmission Capability Notified Transmission Flow Operating Instructions Power System Plesiochronous Digital Hierarchy Power System Stabiliser Pumped Storage Plant Re-switching Secondary Active Power Control Slovak Load Dispatching Centre Slovak Republic Slovenské elektrárne, a.s. Slovak Technical Standard Small Hydroelectric Power Plant Secondary Voltage Control Static Var Compensator Steam Power Plant Stredoslovenská energetika Synchronous Digital Hierarchy Switch Failure Automatics Tertiary Active Power Regulation Telecommunication System Total Transfer Capacity Transmission System Transmission System Operator Transmission Reliability Margin Union for the Co-ordination of Transport of Electricity Vodné elektrárne Dobšiná Vodné elektrárne Trenčín Východoslovenská energetika Západoslovenská energetika Wide Area Network 7 INTRODUCTION The Transmission System Code (TS Code) is one of the most important documents that create a transparent, non-discriminatory and objective environment for those participants in the open electricity market who will want to connect to the transmission system. The TS Code defines conditions, rules, procedures and obligations of the transmission system operator (TSO) at the 400 and 220 kV voltage levels as well as all entities providing or using transmission system services (licensees for electricity generation and distribution, electricity traders, dispatching, telecommunication and information systems, and entitled consumers). The TS Code takes account of the provisions of Directive No. 96/92/EC of the European Parliament and of the Council of the European Union (Directive) concerning common rules for the internal market in electricity in European Union countries. The TS Code respects transitional conditions, processes and the organisational structure of the Slovak power industry within the ongoing transformation and liberation environment. This is however an open document whose underlying principles do not change but whose contents may be updated in the future in view of the new knowledge and the expected changed situation following the restructuring and privatisation of existing power companies. The draft TS Code is prepared by the TSO and approved by the Office for Regulation of Network Industries (ORNI). 8 1 GENERAL PROVISIONS The introduction of a market in electricity is conditional on providing transparency of the TS natural monopoly and TSO objective and non-discriminatory approach to all of its users. Pursuant to the Directive, technical rules establishing technical, design and operation factors, properties and the procedure for the connection of respective entities to the Slovak Transmission System need to be developed and published. Entities means legal or natural persons holding licences to generate electricity, distribute electricity, entitled consumers, and electricity traders. The conditions for connection depend on TS technical characteristics and respect for the rules for international co-operation of the synchronously interconnected system of the Union for the Co-ordination of Transport of Electricity (UCTE). The full use of benefits from the connection to the TS and achieving safe and economical operation is also conditional on the participation in maintaining the system in good operational conditions, minimising the occurrence of failures and their spread. The TSO guarantees the confidentiality of information obtained from users to plan the TS development and control. The same is true of information obtained in traffic. To provide reliable and smooth operation and prevent potential disputes between the users, the TSO must have transparent, objective and non-discriminatory rules, which must be made public. The TS interconnects respective generators, suppliers and consumers and at the same time provides international co-operation in electricity exchanges. These facts put increased demands on the safety and reliability of operation of the TS as a whole regardless of its organisational structure and ownership. In developing the TS Code, the following principles have been applied: each transmission system must be subject to central management and control in order to ensure security, reliability and efficiency of the system in the interests of producers and their customers, the transmission system operator must behave toward all producers in a transparent, objective and non-discriminatory manner, technical rules for the operation of transmission systems and connection thereto must be precisely defined, transparent, objective and non-discriminatory criteria must be established for the dispatching of power plants, provisions must be made for safeguards and dispute settlement procedures, any abuse of a dominant position or any predatory behaviour must be avoided, rules are independent of the organisational structure of the power industry and ownership relations, the rules concern exclusively the technical conditions for the operation of the TS and the provision of transmission and system services to the present and potential users of the transmission system, 9 The TS Code is developed by the TSO and takes effect upon approval by the Office for Regulation of Network Industries (hereinafter called the "Office"). The TS Code is given for review to the current and potential users through the Internet on the web page www.sepsas.sk Unless any agreement is arrived at between the TSO and a particular user, a dispute shall be settled with the Office involved. To settle a case, both parties shall submit their background papers and opinions. Further action shall be governed by the rules of the Office that shall give a final ruling on the dispute in question rules. The TSO has the right to settle disputes independently and promptly where there is a risk of a delayed ruling. Thereafter the dispute shall be settled with the Office involved. Cases entitling the TSO to deal with a problem independently and expeditiously include a threat to safety and reliability of the TS operation, default on the TSO´s obligations under its membership of international interconnected systems, a threat to the supply to consumers, damage to the rights of other TS user, etc. The TSO has the right to carry out operational checks, measurements, monitoring of and control for compliance with the conditions for the connection to the TS and the performance of support services provided to TS users. 1.1 Transmission system The transmission system ensures the transmission of electricity from generating plants to the distribution grid and major consumers at voltage levels 220 kV and 400 kV and in part 110 kV (supply to certain consumers). Electricity imports, exports and transits and precise measurements are effected over lines and electric stations of the transmission system. Part of the TS shall be the TSO Dispatching Centre (SLDC - Slovak Load Dispatching Centre) and its technical provision. 1.2 Transmission system operator The TSO shall be responsible for safe and reliable operation and development of the TS. It shall carry out this through TSO operational and development units and dispatching office. The TSO Dispatching Office shall real-time manage the operation of the transmission system, provide permanent balance between the generation (sources, imports, exports, transits) and the consumption of electricity in the Slovak Power System as a whole and provide electricity exchanges on an international scale. 1.3 Transmission system users The TSO shall provide on a contractual basis transmission and system services to all customers satisfying the conditions for connection to the TS set out herein. Upon entering into contractual relation, they shall become TS users. A TS user shall be a natural or legal person supplying, consuming or trading in electricity. A user can be: producer of electricity (hereinafter called the producer), consumer of electricity (hereinafter called the consumer), licensee for distribution (supply and sales to its customers). 10 In connection with the planning of operation of sources and of the TS, all its users shall be obliged to co-operate with the TSO Dispatching Centre in the preparation of annual, monthly, weekly and daily plans of the operation of the Slovak Power System and to that end provide it with necessary background papers at the established dates. The dates for handing over background papers and their material contents on individual planning phases are defined in Chapter 5. 1.4 Transmission system operator responsibilities The TSO shall be responsible for: TS operation, maintenance, repair and development of interconnectors (and equipment related thereto) with neighbouring systems, the preparation, application and publication of technical conditions for connection to the TS, their objectivity and equality for the same customer categories, reliable status of technical provision for TS management and international co-operation. The TSO Dispatching Centre shall be responsible under the Dispatching Regulations of the Slovak Power System and the related Operating Instructions (OI) for: management of electricity flows in the system while respecting exchanges with the other interconnected systems, ensuring a secure, reliable and efficient electricity system and, in that context, for ensuring the availability of all system services, for dispatching control of energy flows on the system, keeping records of its requirements for suppliers, consumers and other partners, handling emergencies in operating the TS. 1.5 Basic tasks of the transmission system The TS basic tasks include the provision of transmission and system services to customers. The TSO shall be purchasing some of support services to ensure system services for the system. 1.5.1 Transmission services The TSO shall provide transmission services under contract. Within transmission services, customers shall be provided with: connection to the system, electricity transmission by the customer´s requirements as follows: - from the source of generation to the point of offer to customer (from domestic source to the distributor), - from the source of generation to the point of consumption (from domestic source to the entitled customer), - from the source of generation to the border with another interconnected system (exports), - from the border of one interconnected system to that of other interconnected system (transits), - from the border of one interconnected system to the point of offer to customer (imports from foreign suppliers to the distributor or other licensee), 11 - from the border of one interconnected system to the point of consumption (imports from foreign suppliers to domestic entitled customers) The TSO shall connect to the transmission system any customer and provide it with electricity transmission, if the customer so requires and complies with the technical conditions laid down herein and commercial conditions. The TSO shall not be obliged to carry out connection and transmission in the event of provable lack of the transmission capacity of installations or a threat to the TS reliable operation. Non-contractual disruption of the integrity of the Regulation Area by connecting and disconnecting take-offs enhancing or reducing the need for control shall not be allowed. 1.5.2 System services System services shall be activities carried out by the TSO to ensure the operating efficiency of the power system, quality and reliability of electricity supply from the transmission system and the renewal of synchronous operation in PS disintegration. The TS shall provide the following system services: control of frequency and exchanged capacities, hot and cold source backups, voltage and reactive power control in the TS, transmission stability, renewal of operation on full or partial system disintegration (synchronism or power supply loss). 1.5.3 Support services Support service providers shall be operators whose installations are capable of providing to the extent to be specified by a mutual contract some of support services in the quality and in the way to the technical conditions set out herein. The TSO shall purchase from the support service providers through bilateral contracts the following services: unit capacity primary control, unit capacity secondary control, unit capacity tertiary control, quick-starting reserve capacity, cold reserve, U/Q control, preparedness for black start-ups, preparedness for island operation, provision of lines, transformers and transformer plants of distribution for black start-ups. To ensure support services, the TSO shall carry out: co-ordination activity and participation in comprehensively handling the problems of technical and organisational interdependency of these services in operation and concept terms, systematic checks and evaluation of quality and fulfilment of services in question, co-operation with foreign partners. 12 2 CONDITIONS FOR CONNECTION TO THE TRANSMISSION SYSTEM The TS connection rules shall lay down technical and design criteria and procedures to be followed in planning and development of the system. The rules shall apply to all TS users in planning and developing their equipment to the extent they affect the TS. The connection regulations shall establish the requirements for connection and provision of information or recommendations by the TSO to users. The TSO shall provide information or recommendations at the user´s or potential user´s request. A final decision in technical connection matters shall fall within the TSO´s competency. 2.1 Objectives of the connection rules The mission of the connection rules is to: Furnish the TS user sufficient information to assess the possibility of connecting, planning and developing own equipment to ensure compatibility with the TS. Allow for planning, design and building of the TS so as for it to function reliably and safely. Allow for TS uses by all entities meeting the conditions for connection and lay down the conditions for electricity supplies. Ensure technical conditions making it possible to interconnect on the TS interface. Institute exchanges of data necessary to plan the TS operation. 2.1.1. General conditions Meeting the conditions for connection and operation shall be considered the underlying condition to enter the system and shall be complied with by all TS users. The rules shall be subject to development changes, which shall be published once approved. New TS users shall satisfy all the conditions in order to be connected to the system. Users who are already connected yet fail to satisfy particular requirements of the TS Code shall adapt their technological equipment in the next reconstruction thereof. TS users shall inform promptly the TSO of any changes to the availability of their generating or take-off installation. The user shall be obliged to fulfil its production and load curve confirmed by the TSO insofar as the system is in normal condition. In emergencies the dispatching regulations shall be followed. An entitled customer who is interested in connection shall apply with the TSO for connection to the TS in a given location. It shall attach to the request data necessary to decide on the connection pursuant to the Code. Based on the applicant data, the TSO shall draft a technical solution to the applicant´s connection for charge at the agreed date. The results of the proposal shall be a recommendation for connection, being conditional on complying with the requirements, or a refusal of connection. The TSO shall review on demand of the TS user at its expense as to whether system conditions in the point of connection are sufficient to operate the user´s equipment. It shall also 13 review the quality of voltage and adverse back effects on the grid (harmonic, flicker, jump changes in load, asymmetry, etc.) and other users. The TS user shall supply the TSO with all technical and operational data required to assess the connection and shall co-operate in finding technical solutions to comply with the conditions for connection to the TS. Should the system conditions in the point of connection not be appropriate to the TS operation in line with the provisions and trouble-free operation of the user covered by the application, the TSO shall consult the user over the possibility of reducing demands to the extent fit for the TS. 2.2 Technical conditions for connection of consumers A point where electricity is consumed or supplied between the TS and the user shall be the point of connection. The point of connection shall be the boundaries of installations of the TSO and the user. The point and the method of connection shall be established in accordance with the Code. The consumer shall have its degree of technical provision for electricity supply defined by the current technical way of connection of the point of consumption to the TS as follows: basic provision for supply - the intake point is connected with two lines from a single supply point of higher voltage, reduced provision for supply - the intake point is connected with one line from the supply point of higher voltage, increased provision for supply - the intake point connected with two or more lines from two or more supply points of higher voltage or with another line of lower voltage. The consumer shall attach to the connection application approved documents on power part, intake equipment, and on the nature of off-take affecting the TS approved by the transmission system operator. The consumer shall inform the TSO of the existence of any facts that might affect the TS operation. Furthermore, possible co-operation with other systems shall be discussed and authorised. The TSO and the consumer may agree to the amount of intake of the consumer from other systems, which shall not require the TSO consultation and authorisation. The consumer shall respect the provisions of this Code and relevant Slovak technical standards (STN´s). 2.2.1 Active energy take-off Active energy take-off by the consumer shall not cause the maximum permissible current loads of any elements in the point of connection (transmission at TSO substation) to be exceeded and realise the values for capacities of respective stages in the demand restriction plan, the emergency tripping plan, and the frequency plan for load relief pursuant to Slovak Ministry of Economy Regulation No. 180/2000 Coll. Before starting electricity take-off and at dates under relevant operating instructions, consumers shall agree with the TSO Dispatching Centre and realise the values for capacities, of respective stages in the control, tripping plan, the automatic frequency plan for load relief, the demand restriction plan, the emergency tripping plan, and the frequency load relief plan pursuant to Slovak Ministry of Economy Regulation No. 180/2000 Coll. 14 For take-off to be approved, the consumer shall submit by TSO requirements for the following years the values for active load in the annual maximum and minimum divided into take-off and source parts. The consumer shall be obliged to submit take-offs by nodes. 2.2.2 Reactive energy take-off The consumer may take off electricity permanently with the value for load power factor cos 0.95. The consumer and the TSO may also agree to another way of reactive energy take-off control or, as the case may be, another way of take-off assessment. Given the local nature of voltage in the PS, voltage values in respective points vary and are controlled to the values established by the TSO Dispatching Centre. In the point of connection of the consumer the voltage is affected by take-off, therefore the consumer and the TSO shall be obliged to work with one another on voltage control and reactive energy take-off. For take-off to be approved, the consumer shall submit the reactive load values in the annual maximum and minimum, divided in take-off and source parts, for the following years as required by the operator, and in case of a low take-off power factor it shall agree a schedule for its compensation. The consumer shall be obliged to submit take-offs by nodes. 2.2.3. Consumer´s influence on voltage quality A new consumer shall make sure in connection to the TS that the voltage quality limits are not exceeded due to its influence. If it proves in setting the technical conditions that an excess might occur, measures on lowering deviations from the quality indicators shall be agreed to between the new consumer and the TSO. Connection to the TS shall not be possible until after the agreed conditions have been met. These indicators shall not apply to states in transmission system failures. The electricity quality is influenced by the TS as well. The quality shall be ascertained through measurement in co-operation between the consumer and the TSO. If the result of the measurement proves a breach of the quality, such breach shall be remedied by that who causes it. Voltage quality factors to be followed shall be: frequency, voltage magnitude, voltage rapid changes and variations, content of higher harmonic, voltage asymmetry, supply voltage drops and disruptions The method of assessment and permitted deviations for respective factors are shown in Annex 2. 2.2.4 Other requirements for data from consumers The consumer shall provide the TSO for the year of connection and the following 5- and 10year outlooks with an electric single-pole diagram of own distribution including transformer factors and description of appliances over 1 MW. Consumers holding a license to distribute electricity shall provide for the year of connection and the following 5- and 10-year outlook a single-pole scheme of take-off nodal areas with interconnections and single-pole diagrams of 110 kV substations in connection points of the TS. 15 Moreover, consumers shall provide for the year of connection and the following 5- and 10year outlook their minimum and maximum short-circuit contributions for three-phase and singlephase short-circuit currents in the connection points. The minimum values for short-circuit power for TS voltage levels shall be established as follows: 110 kV 700 MVA (classified items) 220 kV 1000 MVA 400 kV 2000 MVA 2.3 Conditions for connection of production units The TSO shall establish for new and reconstructed production units the basic requirements that are the condition for their connection to the TS. All technical equipment serving to connect a production unit shall comply with the requirements set out herein. A licensee for electricity generation shall apply with the TSO to connect a new production unit to the TS. The applicant shall provide the TSO with necessary information along with the application. Provided information shall be used to develop a model for TS grid calculations and undertake an analysis to be paid by the applicant, under which the method and the point of connection and necessary voltage level therefor shall be decided. Should the analysis of connection or change to the existing connection suggest that a more detailed assessment is needed, the production licensee shall furnish additional information. The producer shall be further obliged to build up at its own expense by TSO instructions necessary measurement, signalling, and an ASCS terminal for the purposes of supervisory control and PS control. For more detailed technical requirements see Chapter 6. 2.3.1 Data from production units A production licensee shall provide the TSO on the connection application with the following basic data: Power unit factors: - source location, unit type, source electric diagram, - apparent power, active power, cos , - line rated voltage, - maximum and minimum active unit capacity, - primary control reserve, scope for secondary control. Synchronous generator factors: - synchronous generator no-load characteristics (stator voltage dependence on excitation current) - no-load excitation current - P-Q diagram - function and set-up of stator current limiter - types of used generator protections and set-up thereof 16 Exciter factors: - type of exciter - exciter amplification and time constant - voltage controller structure and factors - excitation limit controller structure and factors - rotor current limiter function and set-up Turbine and boiler factors: - power governor and frequency corrector structure and factors - block diagram - valve opening characteristics P = f(opening) Turbine factors: - Pmax - maximum output - Pmin - minimum output - R - frequency corrector statics - VM - maximum speed of output increase - Vm - maximum speed of output reduction - TTURB - turbine time constant - DBf - frequency corrector insensitivity zone Block transformer and station-service transformer factors: - type of transformer, type of winding connection and hourly angle, - rated apparent output of windings, - rated voltage of windings, - stability of windings, impedance voltage between windings, - no-load and impedance losses, - no-load current, - description of transformer control, - source own consumption factors, - self consumption active and reactive take-off, - self consumption rated voltage. 2.4 Technical conditions for transit The requirements for electricity transit shall be brought forward to the TSO Dispatching Centre. All transit trades should be checked up through grid service calculations using the n - 1 criterion in order to ensure reliability and safety of the TS operation. Active power transit shall not cause an excess of the maximum current loads of any elements of line outlets in any of the TS electric stations. In providing transit the TSO Dispatching Centre shall co-operate with the Warsaw-based CENTREL Control and Accounting Centre, CENTREL´s load dispatching centres, and other states´ load dispatching centres. The TSO can refuse or correct a electricity transit requirement on the grounds of: provable lack of the transmission capacity, a threat to reliability of the system operation, 17 an aggravation in electricity quality factors. Holders of a license for trade in electricity shall present well in advance the TSO Dispatching Centre for approval with all discussed transactions with respect to the TS possibilities and follow its decisions. The TSO has the right to restrict or discontinue to a necessary extent real-time electricity transit in the following cases: in an immediate menace to safety, health or property of individuals and in handling such states, in emergencies 2.5 Technical conditions for real-time control To ensure reliably supervisory control of the TS and the PS as a whole, it is necessary to lay down technical conditions for dispatching measurement and signalling. Technical conditions shall be understood as a minimum and shall be adopted and observed by all TS users. 2.5.1 Dispatching measurement and signalling Voltage measurements shall be made in all the three phases with a minimum total accuracy of 1 %, with each of the measurement chain members having a accuracy of no less than 0.2 %. Current measurements shall be made in all the three phases with a minimum total accuracy of 1 %, with each of the measurement chain members having an accuracy of no less than 0.5 %. Active and reactive power measurements shall be made with an accuracy of no less than 0.5 %. Frequency measurements shall be made with an accuracy of no less than 1.5 mHz. Measuring converter ranges shall be consulted with the TSO. State signalling of switching elements (switch, disconnector, grounder) shall be two-bit (i.e. four-criterion). Fault, protection, switching element blocking state signalling and other operational signalling shall be one-bit (two-criterion). Switch state signalling shall be done at each phase. The time mark shall be necessary in signalling the switch state, fault signalling and protection measurement activation. The requirements for measurement accuracy and certain characteristics for the needs of ASCS, remote control and frequency, power and voltage control are based on the requirements of working rules for primary and secondary regulation of frequency and active power in the UCTE. 2.5.2 Instrumentation and measuring equipment Instrument transformer shall be installed into line or transformer outlets such that the measurement function is not affected by line or transformer operation via the busbar breaker. Local and remote measurement equipment shall be connected to separate windings of the instrument current transformers (ICT) designed for measurement. 18 A voltage drop needs to be checked in the secondary side circuit of the instrument voltage transformer (IVT). The IVT working load shall fall within the load range for which the manufacturer guarantees the accuracy class. The quality of input and output signals of measuring converters and handover of control quantities shall correspond to that for on-line control circuits. With new equipment or in renewal of old equipment the requirements shall be complied with. The accuracy and times of cycles may be temporarily worse with existing equipment. 2.5.3 Real-time control data transmission The basic criteria for data transmission shall be as follows: communication with Control Information System (CIS) substations shall be designed with two independent transmission paths, compatibility of transmission protocols shall be observed, CIS substation shall allow to set the transmission rate, CIS substation shall allow to set a delta-criterion for respective analogue quantities. Deltacriterion selection for transmission of analogue quantities shall be specified by the TSO. Remark: The requirements for instrumentation for TS real-time management are set out in detail in Annex 3. 2.6 Power system equipment protections Protections of electric machines and the distribution system shall perform the following functions: identify quickly and reliably a fault or excess of the normal operation limit of the protected equipment, in a fault switch off equipment at a time that will keep the extent of damage thereto as low as practically achievable and ensure personal protection from electricity effects, reduce the risk of fire due to thermal effects of short-circuit, make sure that the fault does not spread to other elements of the power system. The conditions for protection on interconnectors between adjacent TS´s shall be co-ordinated bilaterally. Also bilaterally co-ordinated shall be the protection of equipment whereby power plants and consumers are linked to the TS. The co-ordination shall be ensured in terms of used protections and automatics and their set-up. To establish types of protections and automatics and their set-up, short-circuit current and dynamic stability calculations shall be required. The set-up of protections shall be designed in the project and approved by the protections department of the company that operates the protections. The connection of the system and of its respective elements shall be such that equipment can be protected. The protection of TS equipment is given by the plan for TS equipment set-up to be developed by the TS. All TS users shall be obliged to respect fully the plan to ensure safe and reliable PS operation. 19 2.6.1 Technical conditions for protection between the production unit and the transmission system There shall be two types of connection between the production unit and the TS: unit connection via a block transformer and a block line to the TS substation, unit connection via a block transformer to the production unit substation that is connected to the TS substation through a line. In both cases the line shall be protected from each side with at least two protections for all types of short circuits, of which one shall be distance. There shall be ensured that the TS and power plant side short circuits are cut off within 100 ms including the releasing time of the circuit-breaker. For an interface with a block line, the comparison protection and the distance protection shall be combined. For an interface made up of a line between the power plant substation and the TS substation, a combination of the comparison protection and the distance protection or a combination of two distance protections shall be used. The distance protection at each side of the line shall protect in the reserve second zone the busbar of the opposite substation. If a block line at the power plant is terminated with a block transformer, the distance protection shall protect in the TS substation the block transformer with reserve zones. Re-switching (RS) automatics shall be installed on the line following agreement between the power plant and the TSO. RS automatics shall only perform a single-pole cycle secured against the possibility of activity f a multi-pole RS. The switch failure automatics (SFA) shall be installed in the power plant substation and the TS substation against faults at the switch failure. In power transmission via a block line, SFA at the power plant shall be in the chain "block transformer - block line“. SFA shall provide switch-off of all adjacent switches feeding a fault via the switch that failed in switch-off. In case that the power instrumentation diagram so requires, remote switch-off of the switch shall be ensured on the opposite side with SFA. If calculation reveals that a generator stability loss may occur in a fault, the generator shall be fitted (on agreement with the generator manufacturer) with a protection that will disconnect it from the grid once the stability is disrupted. It is advisable to use a protection that can be set up at the number of generator slips. Specifically, the set-up of the number of slips shall be made having regard for the generator design stability. The permitted number of slips in terms of PS operation shall be determined based on calculations. Units shall be fitted with appropriate frequency relays to provide automatic activities in fault changes in frequency specified by the Slovak Power System´s frequency plan. A hazard of stability loss or fault spread can arise in some points of connection of the power plant to the TS under certain fault and operation states. To lower the risk of entire plan failure, system automatic switching off select plant units or reducing their output shall be installed in such a situation. The need and conditions for installing such automatics on the plant and TS side shall be established through calculations. 20 The implementation of other system automatics such as sending an impulse from the TS substation to the utility at switch-off of the TS substation block line with a view to reducing the turbine speed with the accelerator shall be ensured following agreement between the power plant and the US. Two independent point-to-point communication paths are recommended to be used for pulling remote protection characteristics. The connection of communication paths shall allow for their parallel operation and independent operation of one or the other connection path. Operation over one communication path shall only be allowed at a fault of the other communication path and on agreement between the power plant and the TSO. The distance protection characteristics pulling can be operated over one independent point-to-point communication path. The provision for and the set-up of the protection on the power plant side and the TS side shall be the responsibility of the power plant and the TSO, respectively. The set-up values providing time, impedance and current selectivity of power plant protections toward the TS shall be determined by the TSO and for TS substation protections toward the power plant by the power plant. 2.6.2 Technical conditions for protection between consumers and the transmission system There shall be two types of connection between the TS and the consumer: the consumer substation is connected through a line to the TS substation, the consumer is connected to the TSO-owned transformer secondary side. In case of connection of the consumer through a line, the line shall be protected with no less than two protections for all types of short circuits. A combination of the distance protection and the comparison protection shall be used. There shall be ensured that short circuits on the line on the TS and consumer side are cut off with the protections within 100 ms including the releasing time of the circuit-breakers. The distance protection on each side of the line shall protect in the reserve second zone the busbar of the opposite substation. RS shall be installed on the line whose set-up shall be specified by the TSO. In case of connection of the consumer via a transformer, this shall be fitted with at least a transformer differential protection, earth-fault vessel protection and with an oil transformer with a gas relay and other protections as prescribed by the standard. To transmit commands for remote switch of the circuit-breakers, there shall be available two independent point-to-point communication paths. Two independent point-to-point communication paths are recommended to be used for pulling of remote protection characteristics. The connection of communication paths shall allow for their parallel operation and independent operation of one or the other connection path. Operation over one communication path shall only be allowed at a fault of the other communication path and on agreement between the power plant and the TSO. The distance protection characteristics pulling can be operated over one independent point-to-point communication path. The provision for the protection on the consumer side and the TS side shall be the responsibility of the consumer and the TSO, respectively. The set-up values providing time, impedance and current selectivity of consumer substation protections toward the TS shall be determined by the TSO and for TS substation protections toward the consumer substation by the consumer. 21 2.7 Provisions for setting up commercial measurement Commercial measurement shall be made for the purpose of payment for delivered, off-taken, transmitted electricity, daily charging and system service charging. The legislative framework shall be given by relevant legal rules. The performance of and support for commercial measurement shall be ensured by the TSO that shall be obliged those measurement as arise out of effective laws. A set of technical facilities operated by trained staff referred to as the commercial measurement system shall be used for the purposes of measurement. The TSO shall be a partner of the involved parties with respect to the preparation, construction, operation, control and maintenance of the commercial measurement system. The involved parties shall at the same time be entitled to use the commercial measurement system by TSO instructions. Commercial measurement shall take place at the boundaries of the TS and of respective TS users that have been granted a licence pursuant to the Energy Act. A licensee (hereinafter called the entity) shall not start to apply its license until after it has ensured commercial measurement with the TSO. Commercial measurement and the performance of commercial measurement system administration shall be provided by the TSO. Pursuant to legislation in force, commercial measurement shall only be made with specified meters that shall be operated according to the provisions of the Act on Metrology, relevant regulations and effective STN´s. Specified meters shall be part of the test circuit made up of ICT´s and IVT´s, terminal boxes and connection wires of respective secondary circuitry. Also part of the Agreement for Commercial Measurement shall be a measuring point diagram containing schematically indicated transformers, busbars, outlets and the method of measurement. The measuring point diagram shall also include measuring point formulas to establish take-off and supply from the values measured with specified meters making up the measuring set. Measurement diagrams can be mutually approved and confirmed by the partners. The data obtained through commercial measurement shall be stored in electronic format into the system database and may be made available to users under an agreement with the TSO. 2.7.1 Technical conditions for measurement An electric device representing in spatial or territorial terms an independently enclosed and permanently electrically interconnected unit where the electricity flow is measured with one or more specified meters shall be considered to be the point of connection. To the extent that a permanently electrically interconnected unit is disrupted, it shall also satisfy the technological follow-up condition. The measuring point shall constitute the boundary between the TS and the entity, eventually between entities. Supply means the transfer of electricity from a supplying entity equipment or system to an accepting entity equipment or system. The entity shall conclude with the TSO an agreement for inclusion of the measuring set in the commercial measurement system and for the performance of administration in the entity structure, defining the conditions therefor. 22 The entity shall be obliged to ensure in its structures sufficiently rated communication paths toward the measuring set for all parties concerned. The entity shall be obliged to make the TSO an effective revision report on special inspection and testing of energy equipment certifying its technical and operational capability. The TSO shall be obliged to file all documents over no less than 5 years. 2.7.2 Electricity measurement Each entity shall be obliged prior to connection to have a functional measuring set in each measuring point at the boundary between it and the system with a view to measuring electricity flows (supply or take-off). In implementing it shall follow the instructions from the TSO it is to be connected to and those from the commercial measurement operator. It shall be obliged to give the measuring set for administration by the commercial measurement operator that shall be obliged to ensure its operation for charge pursuant to legislation in force. Measurement shall be transparent, with any of the partners involved having access thereto. A specific access solution shall be agreed to with the commercial measurement system operator. The accuracy class for measuring instruments shall be: in case of electricity flows up to 25 MW (medium output in the measuring period) no less than 0.5 sec for the active component and 1.0 for the reactive component, in case of electricity flows over 25 MW over 0.2 sec for the active component and 0.5 sec for the reactive component. Electricity meters shall be connected to classified ICT and IVT cores that shall be of the equal or higher accuracy class as the electricity meters. ICT´s and IVT´s shall also be specified meters and together with electricity meters and leads they shall make up a measuring circuit in which a test terminal box shall also be installed. No other equipment shall be connected to this circuit without the commercial measurement operator´s permission. Electricity commercial measurement at the TS boundaries shall be made continuously at 15minute intervals. Electricity flow data measured during such an interval shall form the basis for accounting and billing. A commercial measurement disruption shall be dealt with by way of agreement of the involved parties on setting substitution values for the time of measurement disruption from other specified meters. If the measurement is discontinued and the amount of electricity from specified meters cannot be precisely established, an affected party (he who feels to be afflicted) shall deal with the situation by proposing substitution values that need to be approved with the operator of a particular system, the trader, and eventually also other entities concerned (the manufacturer, the operator of a cooperating system). The methodology for setting substitution values depending on local conditions as part of the contract for connection to the system shall serve this purpose. For each individual trade the entity shall be obliged to read off the states of all electricity meters at the beginning and in the end of the supply and if it so undertakes under contract, even more frequently. It shall also be obliged to make monthly readoffs of electricity meters always on the 23 last day of the month at 24:00 of the current time (DSET or CET). It shall transmit readings to the commercial measurement system operator at the established time, no later than the first business day upon expiry of the accounting period. The entity shall be obliged to take care of the measuring equipment so as to prevent unauthorised interventions, tampering with seals, damage to installed equipment or their theft. It shall monitor its proper run and report promptly any detected measurement errors both by phone and in writing to the commercial measurement operator. The commercial measurement operator shall check commercial measurement system for proper functions and the measuring set for correct activity. Should it doubt the correctness of the measurements or find an error on the measuring equipment, it shall be obliged to clear the error within five business days. Clearing the error also means a measuring equipment replacement. The commercial measurement operator shall be obliged to verify a meter following written application from the consumer within 30 days from the date of service thereof. In case that the meter is found faulty, the cost incidental to the replacement shall be borne by the measuring equipment. Should none error is found thereon, the cost associated with its testing shall be borne by the applicant. The tests shall be conducted by a state testing shop accredited to verify the type of specified meters in question. In order to guarantee a timely installation of the measuring equipment, the entity shall agree at the latest in developing the project with the commercial measurement operator the positioning and type of the measuring equipment and instrument transformers. The entity shall provide the commercial measurement operator with trouble-free access to the measuring set and related equipment. The commercial measurement operator shall be entitled to check the entity´s equipment through to the measuring equipment. Based on a written request and under previously agreed conditions, the commercial measurement operator shall allow the entitled entity to monitor data from the measuring equipment. 24 3 AUTOMATIC SUPERVISORY CONTROL SYSTEM A top level of the Slovak Power System management, the Slovak Load Dispatching Centre shall ensure all of its functions and activities with as high reliability as achievable. To provide its functionality and reliability, the TSO Dispatching Centre shall use: top control and information system ASCS - SLDC, electric station control and information systems (CIS), production unit terminals ASCS, border terminals (T-TG803), electric station terminals (TG709S, TG809), electric station telemechanic devices (DMSI, DMS-80). 3.1 Technical requirements and backup In the ASCS equipment configuration only major components shall be doubled so as to maintain the functionality. These are usually communication computers, servers, local area grids (LAN) components. In the system, fault resistant mechanisms are supported to an increased extent. This is based on the full utilisation of reliability: on-line computer switchover hot - stand by, interconnection of computers via disk arrays with mirroring of their, LAN doubling with automatic switchover to the second grid once an error or low grid passage is found, new ASCS equipment and co-operating equipment shall use the standardised protocol IEC870-5-101 to communicate and minimise the use of older corporate protocols (TG800, TG709, etc.), requirements for transmission paths shall be determined by the TSO in accordance with effective telecommunications rules, power supply 230 V AC from uninterrupted power supplies (UPS + diesel aggregate). As regards enhancing reliability in supply circuit short-circuit, double central devices (frontends, servers, workstations, LAN´s) shall be supplied by two independent uninterrupted power supplies (UPS´s). UPS check is done through a serial port to the system. communications between communication computers, transmission devices and the LAN is done via optic cables to increase the electromagnetic capacity, Emphasis shall be put on safety, reliability, openness and support for standards. 3.2 Control and information systems of electric stations Control and information systems (CIS´s) of electric stations shall meet complex requirements for a local information, control and management system for an electric station and the requirements imposed on CIS´s by the supervisory control with the possibility for mutual communications with the TSO Dispatching Centre (information flows, commanding, control). 25 The installation of CIS´s shall be required with new (newly erected) electric stations, in case of unmanned operations a supervisory system and a remote control system shall be built up. A CIS shall form the core of an integrated control equipment of an electric station. The CIS concept features a decentralised building. 3.2.1 Technical requirements CIS´s shall be fed by 230 V AC with uninterrupted power supplies. In terms of increased CIS electromagnetic capacity and increased reliability, the station management and control unit (workstation, communication computer) shall be supplied from independent UPS with a backup time of no less 5 minutes. UPS control is carried out via a serial port to the workstation. An information switchboard shall be used as an interface between the technology and the control communication computer, into which working signalling, protection outputs, fault signalling, commands shall be transmitted. A CIS shall allow for remote service access for remote diagnostics and parameter-setting as well as for remote access by the protection staff workplace. The requirements for real-time data transmission are set out in Annex 3. 3.3 Control and information systems of production units The requirements for the accuracy of measurements and certain characteristics for ASCS needs, remote frequency and power control, and remote voltage control shall be based on the requirements for working rules for the primary and secondary frequency and active power control in the UCTE. The TSO Dispatching Centre shall ensure co-operation with ACSC terminals of respective production units. Required functions of the system: SCADA function - remote measurement and signalling, data collection and transmission for the Slovak Power System supervisory control, remote control and secondary active power control of respective units, remote control and secondary voltage control in pilot nodes, group control of reactive power and voltage of generators working into a common node, monitoring of grid emergencies, unit frequency disconnection - defence plan, self-diagnostic functions aimed to recognise fault states of the system proper, visualisation, protocol-making, filing, operating staff warning. The requirements for real-time data transmission are set out in Annex 3. 3.4 Precautions in data exchange In making connections between contorl systems of dispatching centres (or electric stations) independent internal communication paths (classified rents) of the public telephone grid shall preferably be used. Control systems and telecommunication devices shall be protected against unauthorised interventions, the precautions shall be based on hardware and software facilities. 26 If computer hook-ups between dispatching centres are used, communications with counterparts should be effected on a devoted computer. Thus a separation from the control process system shall be achieved, with the separation being supported with own security area. To operate external communication interfaces, softwares developed exclusively to that end should be used, where precautions against external interventions can be concentrated. Standard communication procedures and accesses to the currently available computer grids fail to comply with the aforementioned precautions. Based on security considerations, there shall not be any possibilities for connection between the control computer system of the technological process and other systems such as public data grids, Internet, but also in-house computer grids. 27 4 OPERATION AND DEVELOPMENT OF THE TRANSMISSION SYSTEM Directive No. 96/92/EC imposes on the TSO the obligation to afford access to entitled TS users upon satisfaction of technical conditions. In use of the TS, however, the TSO shall continue to be responsible for the maintenance of reliable and secure operation corresponding to a given status of technology. To ensure these tasks, the TSO should provide, inter alia, the planning of repairs and maintenance of equipment, performance thereof, the development of the defence plan against fault spread, and plan the TS development according to load and generation forecasts. Also all owners of electric station and power plant equipment directly related to the TS reliability and security shall be obliged to ensure maintenance. Grid users shall also be obliged to plan and report requirements for equipment switch-off to the TSO Operation Co-ordination Department and supply all necessary data on planning of the TS development. 4.1 Planning repairs and maintenance The planning of repairs and maintenance shall be a summary of activities and technicalorganisational measures aimed at reliable running of the PS. Maintenance, repair and remedy of fault states shall be the responsibility of the owner of a particular equipment. Maintenance work shall be divided into preventive maintenance and non-scheduled maintenance (remedy of fault states). The purpose of the repair and maintenance planning is to define the underlying rules and establish procedures to ensure fail-safe operation of TS equipment and fix powers and responsibilities of maintenance departments. Under inspections carried out pursuant to the "Preventive Action Regulations" and detected defects, an annual plan for repairs and maintenance shall be developed and adjusted to the annual plan for equipment switch-off. The requirements for TS equipment switch-off in the annual repair plan shall be applied in the TSO Operation Co-ordination Department until the end of the sixth month of the previous year. The approved annual plan for work on TS equipment shall be the basic document for the monthly plan for TS equipment switch-off. All requirements and additions for TS equipment switch-off to the monthly plan shall be transmitted to TSO Operation Co-ordination Department by the 12th day of the previous month. The basis for the weekly plan for TS equipment switch-off shall be the approved monthly plan. All requirements and additions to the weekly plan for TS equipment switch-off shall be transmitted to the TSO Operation Co-ordination Department by 10:00 am of the previous week´s Monday. Non-scheduled work shall only be allowed by the TSO Dispatching Centre in exceptional cases, namely in handling faults involving delay or health or safety hazards. 4.2 Performance of maintenance Maintenance on the TS equipment shall be performed pursuant to the "Preventive Action Regulations" that are available with the TSO. To perform preventive maintenance, technological 28 processes have been developed. Maintenance shall be divided into scheduled, where the Preventive Action Regulations apply, and non-scheduled (extraordinary) due to an operational event. A written document (protocol, record, minutes, report) shall be prepared on work carried out by type of work. The record made on a particular inspection shall be filed upon remedy of detected errors pursuant to the TS internal regulation "Storing and filing writings“ for 5 years. The TSO in accordance with the “Preventive Action Regulations” and with the preventive maintenance plan can change during the performance of work for which the equipment needs to be switched off the method of operation of a particular part of the equipment. The electricity transmission can be restricted in a given site in line with Act No. 70/1998 Coll. while giving effect to maintenance. Intervals at which individual inspections are to be carried out shall be determined by type of equipment and type of inspection and these intervals are shown in the "Preventive Action Regulations". In case of new equipment, the "Preventive Action Regulations" shall be completed on a daily basis pursuant to regulations and recommendations of a particular manufacturer. 4.3 Nature of inputs for planning the transmission system development The TS development planning shall be a continuous activity resulting in ensuring its reliable running. Special attention shall be paid to the co-ordination of TS planning in the points of interconnection with adjacent TS´s that are integrated into the European interconnected system. The result of effective development shall be the provision of standard transmission services in terms of reliability and security. To plan the TS development, the following input data shall be of necessity: trends in electricity consumption in the SR with a 10-year outlook, Slovak Power System load curve, characteristics and capacity of power units of all the generators, annual maximum and minimum load of distribution systems and direct consumers with a 10year outlook, long-term contracts for electricity imports, exports and transits, development of foreign systems, in particular adjacent ones. From the time perspective the TS development planning is divided into: long-term development with time horizons of 5, 10 years and more, medium-term development with a time horizon 2 to 5 years, short-term with a time horizon of up to 2 years. The result of the long-term development is the verification of the adopted development concept and specification of the TS diagram. By respecting uncertainties in estimating the future development reliability of the future TS running can be expected. The 5, 10-year development work results shall be the last stage dealing with functional connections of respective crucial structures from the complex perspective of the entire PS. Dealing with TS outlooks for this time shall be unambiguous as it enters the preparation of respective structures. 29 Medium-term development also specifies the future TS diagram. However this serves first of all to develop concrete investment projects in the TS (new lines and electric stations, extension of the stations and installation of compensation means, etc.). The developed studies address these issues in both technical and economic terms, from the perspective of profitability of solution options. Short-term development shall serve to make decisions on concrete smaller-scale investment projects. It shall also tackle the current problems not addressed in the medium-term development. 4.3.1 Underlying documents for planning the transmission system development The grid development study is the underlying document of the TS development process; it is to follow up and be based on the principles of the energy concept for the Slovak Republic´s energy sector and the responsibility for the implementation of the approved energy concept shall lie with the Slovak Ministry of Economy (MoE). The grid development study shall elaborate the TSO´s objectives and targets and lay down measures and means to accomplish them. The study shall prepare the following areas: development of the TS configuration corresponding to the expected growth on electricity consumption. It shall respect the development objectives of electricity generators, the requirements for connection of direct consumers, and the international co-operation requirements, renewal of outdated equipment resulting from the increase in operation factors, the increase in short-circuit currents, technical and moral life of equipment, provision of transmission services on reliability, stability of operation factors, rationalisation and upgrading of process and control activities. The tool for handling TS problems and analysis of individual grid modes shall be a mathematical transmission system model developed for long-, medium- and short-term development horizons. The TS is modelled with the full diagram of 400 and 220 kV grids. Foreign systems are modelled with full diagrams of co-operating grids or a substitution equivalent. Electrically remote systems are modelled with import and export values in border points. The expected load of transformations from the TS to the distribution systems in respective nodes for a 10-year development horizon and in the basic connection of the consumption area shall be established under background papers from development departments of respective distribution systems. They can be corrected based on macroeconomic studies of the national economy development, while respecting the development of economic sectors, their energy intensity and demographic indicators. The balances shall be determined from measurement of the winter maximum of a particular year. The TS development plan shall be submitted for approval to the Office for Regulation of Network Industries at two-year intervals. 4.3.2 Links between the transmission system and users In planning development, in particular of transformations from the TS to the 110 kV distribution system, in considering the power transmission from new electricity sources and in handling problems being local in nature, close co-operation of the TSO and its users shall be 30 essential. Close co-operation shall in particular be with the holders of licences for electricity generation and distribution that are most affected by grid calculations. Work results are shown in the grid development study containing possible technical solution options with an assessment of their cost-effectiveness. Also co-ordinated with the TS development shall be the development of related DS´s. The aim of the study is to supply optimally all consumers by way of appropriate investment in respective systems. As a result, the study shall establish the shares of investment in these systems. 4.3.3 Data for transmission system development studies The development of TS lines shall be based on the results of the analysis of the present and in particular perspective conditions in the TS. Background papers shall be data on actual load and data on expected trends in load and demand, data on existing equipment in the area and static data on existing and perspective elements of the TS and co-operating systems. DS and TS operators shall exchange data necessary for grid steady service calculations, short circuit calculations and system dynamic behaviour calculations for 5- and 10-year time hotizons. The grid balance model for maximum load calculations shall be based on the DS winter measurement results. The assessment of transmission and voltage relations under minimum load shall be based on the summer measurement results. To draft the development of TS - DS 110 kV transformations, relevant departments of TSO distribution systems shall hand expected capacity balances of sources and consumption in individual nodes. As regads sources, this shall be the site and available capacity of power plants operating to the DS. As regards consumption, this shall be the load of transformers from the TS to the DS (MW and MVAr) in respective nodes. Exchange of data shall be made every year by the established date and in mutually agreed format. Exchanged data shall be used for other than conceptual work without the prior permission from the provider and shall not be to a third party. The current problems and issues of development of TS - DS links shall be discussed at joint meetings of staff of TS grid development departments and of all DS´s to be held on a yearly basis. All electricity generators with capacity directly transmitted to the TS shall hand the TSO the following data: installed and achievable capacity, method of operation and time of use, technical data and constants for generators and transformers. The data to develop a model for foreign co-operating systems shall be exchanged at regular meetings within CENTREL working groups. The data shall be updated every year. These inputs shall serve to develop a model for grid service and short-circuit relation calculations. 4.3.4 Public information The transmission system shall provide on its web page www.sepsas.sk select information on the TS operation and development and publish its annual results of management. 31 4.4 Security and quality of operation of the transmission system The TS can be in terms of operation security, reliability and control in the following states: normal state - the TSO monitors the system state at the established time intervals and respond to deviations in frequency or voltage values and to equipment overload. For such a control it uses active and reactive power reserve sources transmission equipment handling. The TSO Dispatching Centre shall be responsible for operative management of the system, reliable transmission and supply in the TS. faulty state - the TSO Dispatching Centre localises a fault point, ascertain the scope and impacts on consumers supply, electricity generation and foreign transmissions. It deals with renewal of electricity supply and generation and foreign transmissions such that a disruption of the supply or generation is as short as possible. emergency state - in the PS this means an abrupt lack of electricity due to emergency events (natural disaster, process accident or catastrophy), measures by state authorities during the state military alert, long-term lack of energy sources, or owing to a terrorist attack. These events may cause a decrease in or a discontinuation of electricity supply or of energy sources or equipment. Frequency, voltage or transmitted powers in any point of the TS are beyond the range of normal values, in particular if there occurs a discontinuation of supply to consumers throughout the system or a part thereof. In such situation the TSO shall be entitled to envoke special procedures to return the system back to normal conditions within the shortest possible windown of time. Emergency procedures shall allow, for example, for putting a cap on consumption, international supplies and take-offs, the use of the emergency tripping plan, frequency relief, black start-ups of production units and resynchronisation of "isolated islands of local take-off sources “. 4.4.1 Failure spread defence plan and system recovery To prevent system failures from occurring in the Slovak Power System, a co-ordinated preventive and corrective action system has been established with the aim of keeping the PS in interconnected state as long as possible. From this point of view it is necessary to deal in addition to (f/P) frequency and power primary and secondary control measures also a co-ordinated action in major variations in frequency, voltage and power flow, in making use of fast control reserves of the power plants, and a coordinated action in setting up protections on the interconnectors with adjacent power systems and consumers. While there occurs a limitation on electricity consumption and generation, it is crucial that there are not uncontrolled trippings. Even with defence measures applied the PS stability can be disrupted and subsequently disintegrated into smaller units. Such being a case, the aim is to ensure the system disintegration into predefined areas in which the basic operation factors (frequency, voltage) will be maintained so that the conditions for PS operation recovery are created as early as possible. The full PS disintegration cannot be ruled out. In such cases operation of major power plants on their self consumption needs to be maintained. In case of the full failure of the plants it is necessary to provide their start using sources capable of starting less the grid voltage. The aim is to ensure the earliest possible recovery of the entire TS. The defence and recovery plan shall be updated in connection with: PS source part development, 32 TS development, change to PS operation standards, connection of new TS users. 4.4.2 Failure spread defence plan The failure spread defence plan is a summary of technical-organisational measures for secure PS operation. Its purpose is to secure measures designed to prevent faults from spreading and cut failure duration. Defence measures shall be aimed at five fundamental types of dangerous phenomena: high frequency variations, loss of synchronism, hunting, overload, high voltage variations. In frequency variations, the basic measure to take shall be proper activity of f/P primary control of power units. Operation of the units in the primary control shall be planned in weekly and daily load coverage plans. The primary control shall be periodically checked for quality. Another measure in frequency variations shall be providing offset of the load balance through generation mobilisation, secondary and tertiary control. The secondary control shall be managed from the TSO Dispatching Centre using an automatic central controller. All power plants excluding NPP´s shall be fitted technically to operate in the secondary control. The employment of respective power units in the secondary control shall be planned in weekly load coverage plans so that the secondary control reserve is able to offset the requireed change in the balance by the established time. To cover further power failure, there shall be available a power reserve at pumped storage plants and combined cycle plants. In case that a power deficit cannot be offset through generation mobilisation and the frequency falls below 49 Hz, there shall occur an automatic frequency load relief at four stages (49, 48.7, 48.4 and 48.1 Hz), with the total volume of the load to be relieved accounting for over 50 % of the Slovak Power System´s total load. Load frequency relief stages and volumes shall be established on the basis of calculations on short-term stability of the island operation of the Slovak Power System, having regard for the requirements for local frequency relief of respective nodal areas. A limiting requirement for the frequency relief system is that the frequency during the failure will not fall below 48 Hz and exceed 51 Hz. A steady value for frequency upon load relief should be just above the rated frequency value. The frequency relays giving an impulse to trip a particular switch breaker with a view to tripping the load shall function without an additional time delay with an operation time of up to 100 msec. The frequency relays shall be installed with consumers at 110 kV and 22 kV substations. Consumers shall be obliged to provide the implementation of the load frequency relief up to the amount to be established by the TSO Dispatching Centre. The frequency plan applied in the Slovak Power System is set out in Annex 4. Synchronism loss measures shall ensure the TS stability. The maximum duration of threephase short circuits guaranteeing a steady service of the system when not exceeded shall be established using calculations. The set-up of protections shall be derived from these calculations. A 33 real time for tripping short circuits with the protections including a backup tripping shall be less than the calculated maximum short circuit durations. On select inter-system lines and at power plants, asynchronous operation protections shall be installed to disconnect in determined points the interconnected system so as to prevent uncontrolled failures and collapse of the whole of the system. Protections that can be set at the number of slips shall be used. A specific set-up of the permissible number of slips in PS terms shall be established through calculations. The number of permissible slips at power plants shall respect the design stability of the generators. To ensure selective, quick and reliable tripping of short circuits, 400 kV and 220 kV line protections shall be fitted with two distance protections or a combination of distance and differential protections. Each protection shall have a separate DC power supply, be connected to a separate ICT core and act on its tripping coil. These protections shall be completed to include a short-circuit current zero component protection, as necessary. On all of TS system lines a single-phase or singleto three-phase automatic RS shall be effected, with three-phase RS being carried out with synchronism control. In a switch-breaker failure, local backup tripping shall be ensured with switch failure automatics whose time set-up shall be established using dynamic stability calculations. Remote backup shall be provided with second and further zones of distance protections. Distance protection second zones shall be time delayed by 0.4 to 0.6 sec. All 400 kV and 220 kV outlets shall have fault recorders and the line outlets shall have fault localisers. To enhance reliability, it is advisable to combine main protections at one outlet from two manufacturers. Remote co-operation of line protections shall be secured with independent direct poin-to-point communication paths. Hunting can occur in case that the grid is highly weakened (multiple faults) or the generators remain connected to the grid via a long-running line. In order to prevent a weakening of the system due to further tripping of the equipment, all of the line distance protections shall be fitted with a "barrier against hunting“. Dampening of intersystem power swings having a frequency of 0.2-0.3 Hz shall be provided with PSS´s (Power System Stabilizers) to be installed on power plant generators. TS overload measures shall ensure the reliability criterion n-1. Equipment overloads occurring in some of the states n-2 shall be dealt with through automatics and operation mode preparation or preventive interventions by the system operator. The system operator shall be entitled to use the following measures: give an order to reduce or increase generation, suspend work on lines in order to switch them on, adjust the system voltage, rule consumption switch-off when necessary. Voltage variation measures shall be dealt with in 100 MW and over generators through automatic primary voltage control. The purpose of the control is to increase stability of the generators by way of a rapid change in excitation during the transient phenomenon. Part of the voltage primary control shall be stator and rotor current check and excitation check. Automatic secondary voltage control of the pilot nodes shall be implemented in the Slovak Power System from the TSO Dispatching Centre. 34 All 400/220 kV, 400/110 kV, 220/110 kV a 110/23 kV grid transformers shall be fitted with tap changer for under-load voltage control. Transformers having automatic tap controllers keep the voltage constant on the secondary side with a given non-sensitivity and time constant. The time delay principle rests in a quicker control of the transformers at higher voltage levels, thereby preventing mass transformer controls at a lower voltage level. The minimum voltage level on the transformer primary side for which further voltage control would imply an aggravation in the voltage conditions in the system. At this level, automatic locking of further action of the automatic voltage controllers shall be done. As for 110/23 kV transformers, an additional compounding is used that increases the magnitude of voltage depending on load increase. In order to keep the voltage within the permitted range on running out of control possibilities for generators and transformers, the PS shall be fitted with compensating chokes. To maintain the TS voltage within the permissible deviations fixed by a standard, the foolowing other means shall be used: in excess of voltage above 420 kV, the system operator shall be obliged to switch off the 400 kV transmission line, with the principle applying that no one-side power supply can be left in the system, in increasing the transmission line voltage up to 460 kV, overvoltage automatics shall be installed on 400 kV lines to disconnect automatically the line with a time delay of 1-2 sec and on check for the size of line reactive power. With a drop in voltage the system operator shall make use of the following measures: reduces the active power of plant units to release the reactive power (P - Q diagram) and starts hydroelectric power plants, gives an instruction to suspend work on transmission lines, give an instruction to suspend tests in the PS, in areas where there is the minimum voltage in the TS, he shall be entitled in an extreme case to rule consumption switch-off, if a low voltage area lies in a border node and reactive power heads to an adjacent PS, he shall contact the system operator of the adjacent PS to agree a solution. 4.4.3 System recovery plan The defence plan shall be developed from measures having regard for all in principle possible phenomena in the system. An accumulation of faults may lead to a total disintegration of the system or its part. The aim of the recovery plan is to put the affected area of the system into normal operation within the shortest possible space of time. The TS recovery procedure strategy shall be as: in case of a voltage loss of a TS part, the recovery shall be done from the adjacent operated grid, in case of a voltage loss throughout the system, the recovery shall be ensured from the power plants that have remained in operation on self consumption, if there are not available power plants running on self consumption, the start-up of major plants shall be effected using hydroelectric power plants capable of starting without grid voltage. 35 The purpose is to recover self consumption of major power plants within 15 minutes when there is still a prerequisite for keeping the units at such parameters as allow for their quick re-start. Further TS recovery shall continue through gradual recovery of voltage from these major plants. Handling procedures shall be managed by the TSO Dispatching Centre. Voltage recovery and connection of consumers shall proceed in order as follows: self consumption of nuclear power plants (Jaslovské Bohunice, Mochovce), self consumption of major thermal power plants (Vojany, Nováky, Košice) , the Capital Bratislava, major cities (Košice, Trnava, Nitra, Prešov, Žilina, Banská Bystrica), other consumers. The order of connection of other consumers in voltage recovery shall be in accordance with agreed contractual relations. To successfully cope with "black starts", reliable telecommunication connections of dispatching centres with managed objects and the possibility of performing at electric stations even with the grid voltage entirely lost shall be provided. In dispatching centres and at select substations reserve independent self consumption sources shall therefore be provided to allow for the most essential facilities to operate in a failure of the adjacent grids for eight hours or so. It is necessary to ensure the preparedness for„"black start“ over the day, the week and the year (in connection with the maintenance plan, process limitations, etc.). In this context check for the preparedness for such a state can be carried out by the TSO with the provider of this service. For check for the capability of island operation, the TSO has the right to request that a "black start" test be conducted. The programme for tests and their periodicity shall be agreed between the TSO, the utility, and the DS. A significant task shall be the training of system operators and other operating staff on procedures in system recovery and tackling complex faulty states. The system operators training shall be co-ordinated by the TSO Dispatching Centre. The training of other operating staff shall be the responsibility of the holders of licenses for electricity generation and distribution. 36 5 CONTROL OF THE POWER SYSTEM Reliable and secure operation of the Slovak Power System shall be ensured by the TSO by providing system services, developing plans for individual operation preparation stages and operative management of the PS. 5.1 System services System services provided by the TSO shall ensure required quality and reliability factors of electricity to be supplied, while maintaining the agreed balance of the Slovak Power System as a control area of the CENTREL and the UCTE systems. To provide system services, the TSO shall use contractually provided support services. The TSO shall be responsible for the functionality of system services and the provision of support services necessary thereto. The required volume of support services shall be procured by the TSO through purchase from support service providers. The requirements for the function of respective components of system services as well as their inclusion in management activities of the TSO Dispatching Centre can briefly be characterised as follows: 5.1.1 Primary power control Maintaining the primary control reserve at the set value shall is a centrally co-ordinated service provided by the TSO. The purpose of the primary control is to increase/reduce within several seconds the power of the sources included in the primary control (to the extent of the set regulation reserve) in order to clear frequency errors. The primary regulation is proportional in nature and contributes to maintaining the production - consumption balance using a turbine speed or power controller. In interconnected power systems the primary control is a solidarity principle based service. Each control area in the UCTE synchronous grid shall supply its contribution P to redress the power imbalance, which is proportional to the frequency error f in accordance with the UCTE specification. The output to be maintained for the primary control in relevant UCTE control areas shall be calculated for every year from the previous year data according to the participation coefficient. With steady operation of the interconnected UCTE system a failure of 3000 MW must be coped with just through the primary control without using the frequency relief. Each regulation area shall be involved in clearing a fault by its specified coefficient. With a quasi-stationary frequency error of -200 mHz, the power being delivered shall be increased by the value of the entire primary reserve. With a quasi-stationary frequency error of +200 mHz, the power being delivered shall be reduced by the value of the entire primary reserve. The output coefficient for each regulation area i= P/f shall be kept constant, throughout the frequency band 200 mHz, if possible. The primary control reserve to be maintained by each control area shall be capable of activation within 15 seconds in case of failure P 1500 MW and in 37 linear staging between 15 and 30 seconds with P ranging between 1500 and 3000 MW of the interconnected system. 5.1.2 Secondary control of frequency and powers to be exchanged The secondary frequency and power regulation is a centrally co-ordinated service provided by the TSO. The purpose of the secondary control is to maintain the frequency at the rated (required) value and the balance of powers to be exchanged with interconnected systems at the agreed value. The action of the secondary control shall be harmonised with that of the primary regulation. The primary control possibilities shall preferrably be utilised with the secondary control only being applied if a frequency error persists or a deviation from the agreed balance has occurred. The secondary control is proportional-integral in nature and works by the formula below. Pd i i Gi 1 Gi dt Tr i [MW] (5.1) where Pdi - output value of the controller acting on controlled machinery, i - proportional constant of the controller, Tri - integration constant of the controller, Gi - area control error (ACE). The constants i and Tri shall be set up such that recovery of the frequency and the balance to the required value with the secondary controller starts virtually several seconds after a frequency error occurs, within 30 seconds, that the highest value of the primary control power is supplied. The secondary control of the control area shall complete its activity after 15 minutes. The constants i a Tri are closely interrelated. The recommended set-up of the proportional constant i of the grid controller has currently a value of 0 to 0.5. The time constant Tri determines the secondary controller speed with which the controller controls of the machines involved. For the time constant Tri the value is currently recommended to be set up within 50 to 200 sec. The secondary power control can only be used to offset instantaneous deviations of the entire system. It shall not be used to reduce undesirable energy exchange or for other form of offsetting. The central controller shall have the possibility of setting up also a reference frequency other than 50 Hz, namely in case that the UCTE synchronous time needs to be adjusted to the astronomic time. je potrebné prispôsobiť astronomickému času. The hourly programme for balance values agreed between the control area and adjacent control areas shall constitute the desirable value for the balance in the control area secondary controller (programme). In order to prevent major sudden changes in the power on interconnectors with a change to the programme, it is required to turn the sudden change into an ever-changing input of the desirable value 5 minutes before a particular agreed programme change and it ends 5 minutes thereafter, i.e. total change duration shall be 10 minutes. 38 Transits or circle power flows have a minimum impact upon the secondary control of the control area. Since the flows coming out of the control area are equal to the incoming flows, reduced by losses induced by these flows, the purpose of the secondary control, in relation to the transits and circle flows, is to offset this loss power from the control area. The secondary control of the control area is not affected by the takeover of transmission for third parties or circle flows, because the flows coming out of the control area correspond, save losses, to the incoming flows. The recommended secondary control reserve shall be: R 10 L 150 2 150 [MW], (5.2) where L is the expected load in the control area. The secondary reserve control shall be carried out automatically. The maximum deviation of the power to be exchanged in trouble-free operation shall be toward UCTE counterparts within 100 MW. Supply or take-off shall be registered at 3 sec intervals, if possible. The maximum deviation of the electricity to be exchanged in trouble-free operation toward UCTE counterparts shall be 20 MWh.h-1. In case that a major production unit failure is no longer covered by the required secondary control reserve, a tertiary power reserve shall additionally be maintained. This reserve need not to be maintained within a particular control area. 5.1.3 Tertiary power control The tertiary power control is a centrally co-ordinated service provided by the TSO. The purpose of the tertiary control is to support the maintenance of the required control reserve on operated machines and, as necessary, to extend it by the powers of units having short start-up times. This tertiary control reserve shall be used particularly to maintain the agreed balance. The tertiary control shall be any manual or automatic transfer of working points on the turbo generators participating in the secondary control with a view to: guaranteeing sufficient secondary control reserve in terms of its magnitute at a given time, ensuring sufficient power reserve to cover non-scheduled changes in the daily load curve, distribute cost-effectively the power of the secondary control among respective machines. Furthermore, the following shall be considered the tertiary control: connection, disconnection of power (gas turbines, power plants with resevoir, pumped storage plants, increase or decrease in output of operated machinery), redistribution of output of machines participating in the secondary control, change in the balance programme between the interconnected system participants, take-off management. The tertiary or minute reserve is a power that is either automatically or manually connected within the dispatching reserve to get sufficient secondary reserve. It is to be deployed so as to contribute timely to secondary control recovery. The recovery of sufficient secondary control area shall occur within 15 minutes. 39 5.1.4 Dispatching reserve The dispatching reserve is a summary of all source output possibilities that can be used to ensure the balance between the sources and the load in changes to source output or load. The dispatching reserve is divided into: cold, hot, operative (rotating): - primary, - secondary, - tertiary. The dispatching reserve shall ensure: sufficient magnitude of cold and hot reserve by selected probability of source failure and occurrence of large-scale positive load deviations, sufficient magnitude of powers for operative reserve (primary, secondary and tertiary control), induced powers in terms of the transmission grid. In developing the dispatching reserve structure for a particular daily load curve, the TSO shall follow either long-term contracts with support service providers or provide (complete) it through short-term (spot) contracts. Also the maintenance of an adequate retention reserve in pumped storage plant reservoirs allowing for pump operation in unpredictable large-scale failures of take-off shall be considered to be part of the dispatching reserve. 5.1.5 Control of voltage and reactive powers In voltage control, a distinction is made between primary, secondary and tertiary voltage controls. The primary voltage control ensures the desirable voltage on generator terminals. The secondary voltage control keeps voltage in select nodes of the grid. The tertiary voltage control is a centralised automatic service co-ordinating the set voltage in pilot nodes for secure and costeffective operation of the PS as a whole. It is effected through an optimising programme run by the TSO Dispatching Centre. The TSO shall be responsible for the operating voltage being kept in respective grid nodes within defined values. For reactive power a balance between its generation and consumption shall be secured within a particular control area. Reactive power transmissions cause a drop in voltage and increase losses, therefore it is desirable to optimise the grid operation so that the local reactive power balance be well-balanced, if possible. The voltage value on border lines shall be harmonised with neighbouring grid operators such that reactive power flows can be handled. If voltage deviations pose a regular problem in adjacent grids, it is necessary to ensure offset means allowing to maintain voltage within the permitted voltage band. 5.1.6 Stability of the power system The PS stability is a co-ordination service ensuring check for static stability in transmission of active powers through grid calculations and dampening oscillations in the system. 40 The PS stability is a capability of the power system to maintain balanced state characterised with synchronous operation of generators, during normal operation and following transient phenomena due to external effects, supervisory control and faulty equipment failures. There is usually made a distinction between the so-called static and dynamic stability. The PS static stability is a capability of the PS to maintain synchronous operation of the generators following transient phenomena in which changes in electric quantities are small and slow. The PS dynamic stability is a capability of the PS to maintain synchronous operation of the generators following transient phenomena in which changes in electric quantities are large and fast (e.g. short circuits). Trouble-free operation envisages that oscillations being transient or permanent in nature have a sufficiently low amplitude or will be sufficiently damped so that the grid operation is fail-safe and secure. Prospect analyses have been undertzaked to that end. Steady synchronous operation of production units is the precondition not only for secure and reliable interconnected operation, but also for supply to the customer. Dynamic operation of the power system is the result of compliance between production units, the transmission system and customers with their relevant control facilities. The grid service is evaluated and co-ordinated as a whole through the TSO. Steady operation shall be secured using appropriate specification of parameters for equipment at power plants, in the grid and customer equipment. Therefore production units and equipment of the customer connected to the grid shall comply with the minimum technical requirements set out herein. If certain levels of power transmission are found to have a destabilising effect, the TSO shall check and limit or shut them down in an appropriate way. The stability of steady state increases using TSO stabilisers (Power System Stabiliser) and SVC´s (Static Var Compensator) or using other appropriate measures. Transient stability may be increased by cutting time periods for fault remedy. Other measures shall be taken, as necessary (e.g. reduction in the generator rotor acceleration by quickly closing up the driving medium into the turbine). In case of connection of new equipment or essential changes to technical parameters of existing equipment, stability testing shall at first shall be performed together with the TSO to specify measures to ensure stability. 5.1.7 Operation recovery following system disintegration Operation recovery upon system disintegration is a process ensuring gradual recovery of the operation of the power system or a part thereof by way of starting units by feeding voltage over the established routes from the established sources, by forming islands, gradually bringing them in phase and connection of consumers according to the prescribed criteria and priorities. In case of a fault not contemplated in the failure spread defence plan, a complete or partial disintegration of the system may occur. For such faults the TSO shall ensure the power system operation recovery through the System Recovery Plan. Control of and update to the recovery plan shall be provided by the TSO Dispatching Centre. 41 5.2 Source operation planning and co-ordination The TSO Dispatching Centre shall develop at relevant stages plans co-ordinating the Slovak Power System operation in co-operation with all the participants in the electricity market. The aim of these plans is to analyse the expected operation of the Slovak Power System, identify problems and, as necessary, draft and implement appropriate measures, thereby creating prerequisites for secure and reliable operation of the Slovak Power System. Furthermore, this involves the preparation of inputs to other related activities such as grid calculation, calculation of electricity consumption to cover transmission system losses, short circuit calculation, dynamic calculation, TS development analysis, background papers required by state institutions and international organisations (e.g. UCTE, etc.). The plans shall contain in general the following: Slovak Power System load forecast, expected coverage of PS SR load, preconditions for foreign co-operation, PS SR power balance, PS SR energy balance, checking up the possibilities for meeting PS SR needs for system services from the offer of support services from the holders of licences for electricity generation, draft corrections at dates of shutdowns as proposed by production unit operators, final plans for production equipment shutdowns, draft measures for reaching reliable operation of PS SR. 5.2.1 Stages for developing plans The year n means the year in which the development of a given plan is underway, the year n+1 means the year subsequent to the year n, the year n-1 means the year preceding to the year n. The TSO Dispatching Centre shall develop plans at the following stages: study on PS SR operation for the year n+1, monthly plan, weekly plan, daily plan. To develop these plans, transmission system users shall be obliged to provide the TSO Dispatching Centre with all binding background papers to the required extent, format and at appropriate dates. The background papers shall be served in writing or e-mailed. Operational, risk and overall tests shall be carried out pursuant to instructions from the TSO Dispatching Centre. 5.2.2 Study on the Slovak Power System operation for the year n+1 The study on operation of PS SR sources for the year n+1 shall be developed by the TSO by 30 September of the year n on the basis of background papers supplied by electricity market participants and available statistical data. Draft measures and corrections to maintenance dates serve electricity market participants to develop annual plans in order to create prerequisites for secure and reliable operation of the Slovak Power System. 42 The aim is to check up in detail the possibilities for ensuring reliable and secure PS SR operation in the year n+1 and draft measures for co-ordination of maintenance dates for PS SR sources. The study on PS SR operation for the year n+1 shall contain: PS SR demand forecasts by months, PS SR weekly peak forecasts, PS SR load forecast in the year n+1, water level motion plan for reservoirs Orava, L. Mara, Ružín, and Dobšiná, expected schedules for foreign co-operation, schedule for shutdowns as proposed by production equipment operators, draft co-ordinated schedule for shutdowns as proposed by the TSO Dispatching Centre, expected meeting of monthly type daily load curves of PS SR for business days with available sources, expected deployment of PS SR production sources in respective weeks for business days, Saturdays, Sundays and holidays, PS RS power balance at the weekly peak hour, PS SR energy balance by months, analysis of the possibilities of meeting needs for system services by offering support services, draft plan for meeting needs for system services in terms of TSO Dispatching Centre requirements, assessment of expected operation situation in terms of security and reliability, draft corrections to submitted schedules for production unit shutdowns in TSO terms with reasoning, draft measures for reaching sufficient level of reliability and security of PS SR operation. Binding background papers shall be submitted by transmission system users to the TSO Dispatching Centre until 15 June of the year n, unless otherwise specified. Binding background papers from electricity distribution licensees: forecast of type daily load curves of electricity distribution licensees or Mondays, business days, Saturdays, Sundays, respective months and holidays, balance of active and reactive power in respective off-take points of the transmission system, typical of respective months (generation, off-take), short-circuit contributions from individual nodal systems on 110 kV side of nodal substations, forecast of effective electricity consumption by months, structured as consumption from LV consumers and from UHV and HV consumers, by months for the 6th to 12th months of the year n and by months of the year n+1. Evaluation of actuals by months for the year n-1 and the 1st to 5th month of the year n, forecast of electricity consumption to cover losses and other (self) consumption of the holders of licences for electricity distribution by months for the 6th to 12th months of the year n and by months of the year n+1. Evaluation of actuals by months for the year n-1 and the 1st to 5th month of the year n, expected method of covering load under the submitted forecast of type daily load curves structured as purchase from SE, a.s., purchase from independent heat generating companies, 43 purchase by electricity distribution licensees from captive power plant, captive power plant generation for self consumption by consumers, purchase from independent generators, update to installed and achievable capacity of captive power plant for the year n+1, contractual obligations under foreign co-operation. Binding background papers from consumers from the TS: forecast of type daily load curves of electricity distribution licensees for Mondays, business days, Saturdays, Sundays, respective months and holidays, forecast of reactive power balance in TS take-off points, expected method of covering load under the submitted forecast of type daily load curves structured as generation at own captive power plant and purchase from SE, a. s., forecast of effective electricity consumption by months for the 6 th to 12th months of the year n and by months of the year n+1. Evaluation of actuals by months for the year n-1 and the 1st to 5th month of the year n, values for installed and achievable capacity from captive power plant operators, in case of sale of some of generated electricity - energy supply schedule, short circuit contributions to input substation 110 kV (22 kV) side. Binding papers from production equipment operators: Background papers from independent generators and independent heat companies: expected putting of new production capacities into operation in the year n+1, update to installed and achievable capacity for the year n+1, schedules for shutdowns of respective sources in the year n+1, specifications of available capacity of respective production units for the year n+1, generation and supply schedule for the year n+1 under contractual relations with consumer specification. Background papers from SE, a. s.: update to installed and achievable capacity of SE, a.s., generating sources for the year n+1, draft schedule for shutdowns of SE, a.s., generating sources in the year n+1, specifications of available capacity for respective SE, a.s., generating blocks for the year n+1, economic order of deployment of SE, a.s., generating blocks, offered control ranges of respective SE, a.s., generating blocks for primary, secondary and tertiary control of active power and frequency, expected failure rate of respective SE, a.s., generating blocks expressed as average expected capacity failure per year, schedule for generation of SE, a.s., generating sources due to heat supplies, expected flow-rate generation for the pumped storage plant (PSP) Ružín, PSP Dobšiná, hydroelectric power plant (HPP) Domaša and small hydroelectric power plants (SHPP) of Vodné elektrárne Dobšiná (VED) by respective months of the year n+1, type diagrams for deployment of the Váh river cascade for respective months of the n+1 for Mondays, business days, Saturdays, Sundays and holidays for flow-rate provision 50% and 90% until 15 July of the year n. The requirements for shape of these type diagrams shall be submitted by the TSO Dispatching centre until 1 July of the year n to SE VET Dispatching Centre, 44 water level motion plan for reservoirs Orava, Liptovská Mara, Ružín, and Dobšiná for the period from the 10th month of the year n to the 3rd month of the year n+2, preconditions for SE, a.s., foreign co-operation in the year n+1 (individual import, export contracts), evaluation of electricity sales to electricity distribution licensees and direct consumers for the year n-1, for the 1st to the 5th months of the year n and sales outlook for the 6th to 12th months of the years n and n+1, expected schedules for purchase from independent generators and independent heat companies for the year n+1 containing expected monthly volumes for electricity purchase and expected monthly type daily load curves, approved annual plan for shutdowns of SE, a.s., generating sources upon approval in the 12 th month of the year n, consumption characteristics of new or backfitted units of SE, a.s., steam power plant. 5.2.3 Monthly plan The TSO Dispatching Centre shall develop a monthly plan no later than 10 days prior to the start of a particular month. The aim is to prepare a plan for operation of PS SR sources for the following month based on binding background papers from the Slovak electricity market participants and statistical data. The monthly plan shall contain: PS SR power balance at weekly peak hours, expected PS SR load course, plan for water level motion for Orava and Liptovská Mara reservoirs, foreign co-operation schedules, binding monthly plan for generating source shutdowns, expected meeting of type weekly, type daily load curves of PS SR for business days and holidays and monthly type daily load curves of PS SR for Sundays, PS SR energy balance, plan for meeting system service needs based on updated requirements from the TSO Dispatching Centre, evaluation of PS SR operation situation in terms of operation security and reliability for a particular month. Draft measures for enhancing security and reliability, as necessary. Binding background papers shall be submitted by transmission system users to the TSO Dispatching Centre no later than 20 days prior to the start of the month to be processed. Binding background papers from electricity distribution licensees forecast of type daily load curves of electricity distribution licensees for Mondays, business days, Saturdays, Sundays, respective months and holidays, forecast of meeting type daily load curves (including self consumption thereof) structured as purchase from SE, a.s., purchase from independent heat companies, purchase from captive power plant, captive power plant total generation, forecast of effective consumption for the month n+1 structured as LV consumption, UHV and HV consumption, forecast of losses and other consumption of electricity distribution licensees for the month n+1, 45 evaluation of effective consumption for the month n-1 structured as LV consumption, UHV and HV consumption, evaluation of data and other consumption of electricity distribution licensees for the month n-1, balance of active and reactive power in respective take-off points of the transmission system typical of respective weeks (generation, take-off). Binding background papers from TS consumers: forecast of type daily load curves of electricity distribution licensees for Mondays, business days, Saturdays, Sundays, respective months and holidays, forecast of meeting type daily load curves (including self consumption thereof) structured as purchase from SE, a.s., purchase from independent heat companies, purchase from captive power plant, captive power plant total generation, evaluation of electricity consumption for the month n-1, forecast of electricity consumption for the month n+1. Binding background papers from production equipment operators: Background papers from independent generators and independent heat companies: specification of available capacity for a particular month, schedule for generation and supply for a particular month under contractual obligation with specification of the consumer for a particular month. Background papers from SE, a.s., for a particular month: approved quarterly preparation for operation of SE, a.s., sources, tariff ranges for SE, a.s., customers in SR, monthly specifications of available capacity for SE, a.s., generating sources, comment on changes in available capacity of SE, a.s., generating sources against the quarterly operation preparation, economic order of deployment of SE, a.s., generating blocks, plan for deployment of hydroelectric power plants developed based on the requirements from the TSO Dispatching Centre to be submitted by the TSO Dispatching Centre to the Trenčínbased dispatching centre for management of operation of Váh river cascade HPP´s no later than 30 days prior to the start of the month to be processed, D-SE VET shall submit a plan for water level motion of the Orava and Liptovská Mara reservoirs for a particular month, plan for foreign co-operation for a particular month (import, export contracts) planned schedules for purchase from independent generators and independent heat companies containing the expected monthly volume of electricity purchase and the expected monthly type daily curve for purchase from independent generators and independent heat companies for a particular month, update to expected electricity sales to electricity distribution licensees and direct consumers, as necessary (against the quarterly preparation). 46 5.2.4 Weekly plan The TSO Dispatching Office shall develop a weekly plan by 09:00 a.m. of the last business day preceding the appropriate week. The energy week shall begin on Saturday at 00:00 hrs and end on Friday at 24:00 hrs. The aim is to prepare the plan for Power System source operation for the following week based on binding background papers of the participants of the market in electricity in the Slovak Republic and statistical data. The weekly plan shall contain: PS SR power balance at the weekly peak hour, expected PS SR load course, planned foreign co-operation schedule, plan for generating source shutdowns, plan for meeting PS SR peak load curve, plan for meeting system service needs. Binding background papers shall be submitted by transmission system users until Tuesday 10:00 hrs in the week prior to the appropriate week. Requirements of captive power plant operators for operation of their sources for the appropriate week shall be submitted by the holders of a licence for electricity distribution and direct SE, a.s., consumers. Requirements for operation of their production facilities for the appropriate week shall be submitted by independent heat companies and independent generators. SE, a.s., and the TSO Dispatching Centre shall submit for deployment of VET HPP´s the following requirements: the TSO Dispatching Centre shall submit requirements for deployment of VET HPP´s for pickedup days on Tuesday in the week prior to the appropriate week by 08:00 hrs. Based on this, SE VET Dispatching Centre shall develop a plan for deployment of VET HPP´s and the HPP Gabčíkovo, SE, a.s., shall submit economic order of deployment of sources, SE, a.s., shall submit requirements for operation of its production facilities for the appropriate week, SE, a.s., foreign co-operation plan for the appropriate week (import, export contracts). 5.2.5 Daily plan The TSO Dispatching Centre shall develop a daily plan by 13:00 hrs on the day preceding the appropriate day. Insofar as the following days are Sundays, the TSO Dispatching Centre shall develop daily plans for all following Sundays including a plan for the first business day. The aim of the daily plan is to develop a plan as detailed as possible for operation of PS SR sources for the following day, namely based on binding background papers from participants of the market in electricity and statistical data. The daily plan shall be the underlying document for operative management of PS SE operation. The daily plan shall contain: 47 expected PS SR load course, planned foreign co-operation schedule, plan for generating source shutdowns and availability, plan for deployment of PS SR sources, plan for meeting system service needs. Binding background papers shall be submitted by transmission system users by 09:00 hrs on the day preceding the appropriate day. Requirements of captive power plant operators for operation of their sources for the appropriate day shall be submitted by the holders of a licence for electricity distribution and direct SE, a.s., consumers. Requirements for operation of their production facilities for the appropriate day shall be submitted by independent heat companies and independent generators. SE, a.s., and the TSO Dispatching Centre shall submit for deployment of VET HPP´s the following requirements: the TSO Dispatching Centre shall submit the SE VET Dispatching Centre requirements for deployment of VET HPP´s for the appropriate day by 08:00 hrs of the preceding day. Based on these requirements, SE VET Dispatching Centre shall develop a plan for deployment of VET HPP´s. In case that this plan is not acceptable from the TSO Dispatching Centre´s point of view, SET VET and TSO Dispatching Centres shall seek a mutually acceptable solution. The final version of the plan shall be put forward by SE VET Dispatching Centre to the TSO Dispatching Centre by 11:00 hrs of the preceding day. SE, a.s., shall submit requirements for operation of its production facilities for the appropriate week, SE, a.s., shall submit a foreign co-operation plan for the appropriate day (import, export, transit contracts from 110 kV level inclusive). 5.3 Planning and co-ordination of operation of the transmission system The TSO Dispatching Centre shall develop based on requirements from TS operation departments and other TS users a plan for tripping TS equipment at respective operation preparation stages and ensure their co-ordination within the interconnected system. 5.3.1 Annual preparation for operation of the transmission system The annual preparation for TS operation shall be developed based on even power balance for a given year. The requirements for tripping and release of transmission system facilities and classified facilities of the distribution system for maintenance and recovery, commissioning new facilities and decommissioning facilities shall be submitted to the TSO Dispatching Centre through the TSO Operation and Technology Department. Entitled partners for the submission of requirements for tripping TS facilities shall be: 48 TSO Development and Investment Department - submits requirements for planned actions being investment in nature at TS substations, on TS lines and telecommunication equipment of power engineering, TSO Operation and Technology Department - submits requirements for planned actions being operational in nature at TS substations and on TS lines, including telecommunication equipment of power engineering, co-ordinates in date terms requirements from other entitled partners, TS Technical Support Department - submits requirements for planned actions being operational in nature on ASCS, CIS equipment, commercial measurement and telecommunication equipment, operation departments and dispatching centres of electricity distribution licensees - as primary contractual operators of TS equipment they submit requirements for prescribed maintenance work at substations, prescribed work on TS lines and work at substations and 110 kV lives affecting the operation of TS equipment and generating plants of authorised generators working into the distribution system, electricity generation licensees - submit requirements for planned actions on equipment transmitting power and providing self consumption of power plants, others - due to work on ground or for other reasons near UHV equipment. Respective TSO departments and electricity distribution and generation licensees shall submit the TSO Dispatching Centre every year until 31 May lists of all employees entitled to submit the requirements for tripping and releasing equipment. Time stages for the development of the Annual preparation for operation of PS SR grids for the year n+1: submission of background papers to the TSO Dispatching Centre by 30 June of the year n: - requirements from all applicants for tripping and releasing TS equipment and distribution grid classified items through the TSO Operation and Technology Department, - plans for source maintenance from electricity generation licensees, - data on foreign co-operation for grid calculations from trading companies, - background papers for preparation of balances on TS 110 kV transformers from electricity distribution licensees. The requirements for tripping and releasing TS equipment and distribution system classified items shall be precisely described. The requirement shall contain the following data: - detailed description of the reason for putting a transmission element out of operation, - time scope of work, - availability time in switching off. Over the period between 30 June and 30 September of the year n, there shall take place an optimising and co-ordination process of the date of planned shutdowns of power generation equipment, mode of generation equipment to be deployed, planned contractual supplies, additional electricity imports or exports, 49 dates for tripping and releasing distribution equipment out of operation including TS transmission conditions calculations. The TSO Dispatching Centre shall carry out co-ordination of the requirements for tripping and releasing TS equipment and distribution grid classified equipment out of operation with the upcoming mode of operation of generation sources. The aim of the co-ordination is to unify as much as possible the dates of the requirements for tripping and releasing and the dates for distribution of repairs to generation sources. The output of the co-ordination process shall respect the criteria for PS SR operation reliability and security in both transmissions and power balance part. Possible necessary date changes shall be discussed by the TSO Dispatching Centre with appropriate entities during the co-ordination. The requirements for tripping and releasing out of operation international transmission equipment and internal transmission equipment, the tripping and releasing of which affect the operation of international interconnectors, shall be co-ordinated with foreign counterparts. The TSO Dispatching Centre shall exchange the requirements for tripping and releasing out of operation the above elements with the TSO Dispatching Centres of adjacent PS´s. The aim is to unify the dates for tripping and releasing out of operation respective equipment and choose mutually suitable dates following up on other internal requirements. System steady operation calculations a distribution of active and reactive powers and voltage conditions on all modelled elements of the system and shall be used as one of the inputs into the decision-making process operation preparation on feasibility of the mode planned. Input data for calculations are: updated data model of the grid, balance of powers on respective 400/110 and 220/110 kV transformers, deployment if sources with respect to the plan for repair of generation, plan for tripping and releasing TS equipment out of operation, information on dates for expected commissioning of new lines and transformers with their basic parameters, PS SR exports and imports, contractual power transits via the TS, TS element parameters and type parameters of generation units. Within the Annual preparation for TS operation, the PS SR winter maximum basic mode and the PS SR summer minimum mode shall be analysed through calculation. Also analysed in terms of transmission profiles through calculations shall be TS operation modes giving rise to limitations in PS source or consumption areas or limiting power exports, imports or transits while respecting the security criterion n-1. There shall be made at the same time within the Annual preparation for TS operation the calculation of short circuit conditions with the structure of sources corresponding to the deployment on the winter maximum and summer minimum in the basic connection of PS elements. as of 30 September of the year n, the last update shall be made to input data into the Annual preparation for TS grids operation, as of 30 October of the year n, closure shall be made of the Annual preparation for TS grids operation within the completion of the Annual preparation for the power system operation, 50 the TSO shall ensure the publication of the Annual preparation for TS operation until 10 December of the year n. Applicants shall be informed on the approved plan for tripping and releasing TS equipment through the TSO Operation and Technology Department. 5.3.2 Monthly preparation for operation of the transmission system The monthly preparation for TS grids operation shall be developed by the TSO Dispatching Centre. The background paper for the monthly preparation of the transmission system operation shall be the Annual preparation for TS operation. An amendment to the requirements against the Annual preparation for TS operation shall be submitted to the TSO Dispatching Centre by entitled partners through the TSO Operation and Technology Department. The requirements for alteration and amendment need to be brought forward always no later than the 15th day of the preceding month. Additional programme requirements for tripping and releasing transmission system equipment and classified distribution system equipment for maintenance and renewal, commissioning new equipment and decommissioning equipment shall be subject together with the original requirements to co-ordination with the process of shutting down sources for maintenance with the aim described in the annual preparation for grid operation. These requirements may be refused due to failure to respect the criteria for reliability and security of PS SR operation in transmissions and the balance power part. To develop grid modes, electricity distribution licensees shall submit the TSO Dispatching Centre until the 15th day of the preceding month expected transmissions through individual 400/110 kV and 220/110 kV transformers in a particular month for: PS SR monthly maximum and minimum on the monthly maximum day, PS SR Sunday maximum, PS SR Sunday minimum. The calculation of TS transmission and short circuit conditions within the monthly preparation for TS grids operation shall be made as necessary for tripping and releasing TS equipment out of operation that need to be verified in calculation terms with respect to the security criterion n-1. TSO Dispatching Centre departments shall submit for all reconstructions and rated repairs of TS equipment a subject and time programme until the 10th day of the preceding month. A request for risk, operation or contractual tests on TS equipment shall be made by a designate at the dates and to the extent pursuant to the Dispatching Regulations. Additional requirements for tripping and releasing out of operation international transmission equipment and internal transmission equipment the tripping and releasing of which affect the operation of international interconnectors shall be co-ordinated with foreign counterparts with the aim described in the annual preparation for grid operation. The monthly operation preparation shall be submitted by the TSO Dispatching Centre as "PS SR Operation Modes" for discussion at the dispatching monthly meeting. 51 Applicants shall be informed on the approved plan for tripping and releasing TS equipment through the TSO Operation and Technology Department. 5.3.3 Weekly preparation for operation of the transmission system The weekly preparation for TS operation shall be developed by the TSO Dispatching Centre. The background paper for the weekly preparation of TS operation shall be the Monthly preparation for TS operation. An amendment to the requirements against the Monthly preparation for TS operation shall be submitted to the TSO Dispatching Centre by entitled partners. The requirements for alteration and amendment need to be brought forward always no later than Tuesday 10:00 hrs for the following week. Additional programme requirements for tripping and releasing transmission system equipment and classified distribution system equipment for maintenance and renewal, commissioning new equipment and decommissioning equipment shall be subject together with the original requirements to co-ordination with the process of shutting down sources for maintenance with the aim described in the annual preparation for TS grid operation. Additional requirements for tripping and releasing international transmission equipment and internal transmission equipment whose tripping and release affect the operation of international interconnectors shall be co-ordinated with foreign counterparts with the aim described in the annual preparation for TS operation. These requirements may be refused due to failure to respect the criteria for reliability and security of PS SR operation in transmissions and the balance power part. The calculation of TS transmission and short circuit conditions within the weekly preparation for TS grids operation shall be made as necessary for tripping and releasing TS equipment out of operation that need to be verified in calculation terms with respect to the security criterion n-1. The weekly operation preparation shall be submitted by the TSO Dispatching Centre as "Weekly Evaluation of and Preparation for PS SR Operation" for a particular week. Applicants shall be informed on the approved plan for tripping and releasing TS equipment through the TSO Operation and Technology Department. 5.3.4 Daily preparation for operation of the transmission system The daily preparation for TS operation shall be developed by the TSO Dispatching Centre. The background paper for the daily preparation of TS operation shall be the Weekly preparation for TS operation. An amendment to the requirements against the Weekly preparation for TS operation shall be submitted to the TSO Dispatching Centre by entitled partners. The requirements for alteration and amendment need to be put in always no later than 09:00 hrs for the following week, namely only changes against the weekly plan and for unplanned necessary repairs. Changes in the requirements for tripping and releasing transmission system equipment and classified distribution system equipment for maintenance and renewal, commissioning new equipment and decommissioning equipment shall be subject together with the original requirements to co-ordination with the process of shutting down sources for maintenance with the aim described in the annual preparation for TS grid operation. Changes in the requirements for tripping and releasing 52 international transmission equipment and internal transmission equipment whose tripping and release affect the operation of international interconnectors shall be co-ordinated with foreign counterparts with the aim described in the annual preparation for TS operation. These requirements may be refused due to failure to respect the criteria for reliability and security of PS SR operation in transmissions and the balance power part. The calculation of TS transmission and short circuit conditions within the daily preparation for TS grids operation shall be made as necessary for tripping and releasing TS equipment out of operation that need to be verified in calculation terms with respect to the security criterion n-1. The daily operation preparation shall be submitted by the TSO Dispatching Centre as "Daily Preparation of Generation and Distribution Equipment" for a particular day. Applicants shall be informed on the approved plan for tripping and releasing TS equipment through the TSO Operation and Technology Department. 5.4 Consumption control Under bilateral contracts made between the supplier and the consumer, electricity takeoff can be regulated. Takeoff regulation shall then be governed by the principles set out therein. Such a regulation shall be used by the TSO Dispatching Centre under contracts with respective licensees on the offset principle. This is a change in load that does not fall within the category of changes that are compulsorily made by the limiting, emergency and frequency plan (MoE Regulation No. 180/2000 Coll. on emergencies in the power industry. 53 6 REQUIREMENTS FOR SOURCES The operation of each power system requires that the units of its generation base satisfy precisely specified requirements conditional for its secure and reliable service. The stated rules for PS SR sources specify the basic requirements for the quality and scope of support services to be met by these sources and specify also the requirements for capability of the units, their automatics and protections to perform necessary functions under both normal and extraordinary operational states in the PS. 6.1 General requirements for generating units New or renewed 110 MW and over NPP, SPP units, combined cycle units with a total plant installed capacity of 50 MW and over and HPP, PSP units with a plant total installed capacity of 10 MW and over, connected to the TS or the 110 kV distribution grid shall meet the following requirements for their start times, power changes and ensuring self consumption: Unit shutdown duration < 8 hrs 8 - 50 hrs > 50 hrs Unit state Max. start time up to full load hot warm cold 2 hrs 3 hrs 5 hrs Tab. 6.1 Start times for new thermal units N.B.: Fluidised bed boilers will be specified individually. Tab. 6.2 Required changes in power for new instalments Change in power Change in power (%Pn) Mean change in speed c (%P n .min-1) Minimum change in power (%Pn) Gas, mazut Semianthracite coal Brown coal Gas turbine Combined cycle unit PSP, HPP 40 - 100 40 - 100 40 - 100 60 – 100 60 - 100 40 - 100 8 2-4 1-2 6-18 90 - 150 6 60 60 60 40 40 60 6.1.1 Special requirements for units Units (excluding NPP units) shall be capable of no less than 200 starts and shutdowns per year. All units shall be capable of being brought to phase of the system within the frequency area of 48 to 51.5 Hz. 54 6.1.2 Self consumption Self consumption of any power plant shall be ensured such that electricity demand for operation of its technology can cover with self-generated energy. Any power plant shall ensure: in disconnecting the unit from the grid using the outlet protection because of faults outside of the unit (not unit protection), the unit will automatically switch over to self consumption, the aim of keeping the unit on self consumption is the capability to connect quickly the unit to the grid upon remedy of the fault, disconnected unit (outlet protection) shall be capable of staying on self consumption for at least 2 hours. 6.1.3 Recovery plan requirements In an interconnected system faults can spread very quickly covering large distances. Despite all precautions in operation it cannot be ruled out that the PS SR will find itself temporarily in a strained operation situation. Experience has shown that in such situations even a simple, otherwise common, event can turn into a major fault. Therefore the source operator shall take necessary action to restrict (if possible) the consequences of the fault to a small area. The electricity generator shall ensure: At a frequency of 47.5 Hz to 53 Hz the generator units shall switch automatically over to self consumption. Keeping the generator units on self consumption aim to restore swiftly the PS voltage at system disintegration and full voltage loss. In case that the generator units fail to keep themselves on self consumption and a full voltage loss at the same time occurs, they shall be ensured such that they are capable of starting according to the operating regulation and run even under island operation mode. once the voltage is regained from the outside. Hydroelectric power plants, which are capable of starting without grid voltage, shall be obliged in "black starts" to start into operation by TSO Dispatching Centre instructions and effective operating instructions with the aim of restoring self consumptions of large power plants. The preparedness of these plants for "black starts" represents a support service contracted by the TSO. With newly-built power plants the TSO shall give its opinion on the need to fit power plants for use in "black starts”. 6.2 Support services To ensure "system services“, the TSO shall make use of "support services“. They shall be provided in particular by generation licensees who shall at the same time be also TS users. From the perspective of TS users, the division of support services into obligatory support services and support services under an agreement. The participation in obligatory support services shall be an essential condition for a user to be connected to the TS. All support services shall satisfy the following requirements: measurability by specified parameters, guaranteed availability of a service when required by the TSO, checkability by the specified method. 55 The TSO has the right to check up the quality of all support services provided for the TS. The quality check-up shall be carried out using TSO technical facilities (central contoller, ASCS terminal) or directly on the support service provider´s equipment in the presence of TSO staff. Demonstration needs to be carried out pursuant to the methodologies set out in Section 6.3 herein. For the impartiality of assessment for the capability to provide respective types of support services, the certification measurements of support services set out in Sections 6.2 and 6.3 are expected to be made by an independent authorised entity. An overview of respective types of support services providing TSO system services: primary power control, secondary power control, tertiary power control, quick-starting unit start, reserves (cold, warm, hot), secondary voltage control, compensation operation, island operation capability, voltage-free state start capability. The breakdown of support services by the obligation of their provision: Obligatory support services that are the condition for connection to the TS: - primary power control, - secondary power control, - tertiary power control, - secondary voltage control, - island operation capability. The scope of obligatory fulfilment of respective obligatory support services to a particular generator connected to the transmission or 110 kV distribution system shall be laid down by the TSO. Optional support services provided under an agreement: - quick-starting unit start, - reserves (cold, warm, hot), - compensation operation, - voltage-free state start capability. 6.3 Active power regulation The requirements for active power regulation for various modes of providing support services concern all units (turbines) rated 10 MW and over. 6.3.1 Breakdown of unit active power The breakdown of unit active power is shown in Fig. 6.1. 56 Pn rated output Primary control reserve Control range for tertiary control Control range for secondary control Pmin technical minimum Primary control reserve Basic control range of tertiary control P0 zero output Fig. 6.1 Breakdown of unit active power 6.3.2 Requirements for primary active power regulation The primary active power regulation is an automatic activation of the turbine output merely based on changes in the grid frequency. The regulation is very fast and shall meet: the rate of primary reserve activation shall activate the relevant output contribution P of the turbine: - at f deviations 100 mHz within 15 sec, - at 100 f 200 mHz the relevant output contribution P of the turbine shall activate in a linear way between 15 sec and 30 sec. primary regulation reserve of the turbine should be no less than P = 5 Pn, insensitivity of turbine contollers n 10 mHz. 6.3.3 Requirements for secondary active power regulation The secondary active power regulation is an automatic control of the turbine output from the dispatching centre within a pre-defined control range with the agreed speed of load changes c. The secondary active power regulation shall be activated within 30 seconds from the occurrence of a fault and start to offset the frequency and the balance to the required value. The secondary active power regulation should terminate its activity within 15 minutes. Furthermore, the secondary active power regulation shall meet: the turbine output governor shall be remote controllable, the unit shall allow for permanent power changes within a minimum range of 10 % from rated power, the control range of the unit and the unit output change rate shall be by Table 6.2 “Required Power Changes for New Equipment”. 6.3.4 Requirements for tertiary active power regulation Units that are used to secure tertiary control shall make use of the entire control range for the tertiary control according to Fig. 6.1 with power changes by Table 6.2. Units that start from zero 57 power shall supply the grid with a power corresponding to the basic power of the tertiary control by Fig. 6.1 (unit technical minimum). Units ensuring the tertiary control shall provide: required jump change in active output of the turbine from the secondary output controller, required jump change in active output of the turbine from the TS dispatching centre with units connected to the secondary control, quick start or shutdown of the unit either automatically or manually, quick unit load. 6.3.5 Requirements for active power reserve Quick-starting units shall be capable of starting up to the full power from the dispatching centre command within: 5 minutes hydraulic, 15 minutes gas. Units included in cold reserve shall be capable of restarting from the dispatching centre command according to Section 6.1. 6.4 Voltage regulation The set out requirements for voltage regulation regard all generator units having an output of 50 MW and more. 6.4.1 Requirements for primary voltage regulation Generator units shall have the primary voltage regulation at such technical level as to meet the regulations for voltage regulation and PS stability. The primary regulation with quick change in excitation during a transient phenomenon shall keep the required voltage on the terminals of the generator unit while maintaining its stability. Part of the generator voltage governor unit shall be: control for stator and rotor current limits, control for underexcitation limit, Power System Stabiliser (PSS). 6.4.2 Requirements for secondary voltage regulation The secondary voltage regulation in the pilot node shall be made by changing the magnitude and nature of reactive power. The required reactive power in the pilot node shall be ensured using generator units or compensation means. The magnitude and nature of reactive power of the generator unit can be ensured by changing its excitation within the operation part of the P - Q diagram. Reactive power of the generator unit and the pilot node may also be affected by switching over the taps of its block transformer. A generator unit which is to run in the secondary voltage regulation shall satisfy the following: generator voltage regulation shall be adapted to automatic remote voltage regulation in the remote pilot node of the power system, 58 block transformer and self consumption transformer shall have switchable taps under load as a minimum 8 taps 1÷2 % of Un each. The tap switchover regulation shall be part of automatic remote voltage regulation in the remote node of the power system, if two or more generator units run into the common node (parallel operation), they shall be fitted with group regulation of voltage and reactive power, the P - Q diagram operating range can be limited against the P - Q diagram supplied for a particular generator unit by the manufacturer in the negative part by 10 % of the maximum permissible reactive power and in the positive part by 15 % of the maximum permissible reactive power. 6.5 Methodologies for verification of support services The capability of units to ensure respective support services shall be verified according to methodical procedures to be issued by the Office for Regulation of Network Industries. 6.6 Requirements for protections and automatics 6.6.1 Requirements for electric equipment protections Generator units rated 5 MVA and higher shall usually run in the block with HV/UHV transformers, self consumption transformer and exciter. Such an arrangement shall include protections set out in Table 6.3. Protection Generator Differential short-circuit Distance short-circuit Over-current short-circuit Excitation loss Against asynchronous run Asymmetry Overload Reverse power Ground stator Thread Voltage Bearing currents Frequency Frame Gas relays Ground rotor N, 3 N N N D N N N N N, 1 N, 2 N N N Electric equipment Block Tap transformer transformer N N N - Table 6.3 List of electric equipment protections Legend: N - necessary protection, 59 N N N, 4 N - Exciter N N N N N D - recommended protection, 1 - in parallel taps of alternator stator, 2 - two protections - mutual backup, 3 - two protections (unit and alternator) - mutual backup, 4 - in front and behind transformer. 6.6.2 Requirements for automatics Every electricity generating plant shall have installed the following protections to ensure stability of the power system: re-switching, switch failure, switch remote switch-off, protection connection path switchover, switchover of power regulation from frequency change, remote power regulation, remote voltage regulation, to ensure switchover to self consumption at emergency frequencies. 6.6.3 Basic requirements for unit management systems Real time management systems of the generating plant shall have two management levels. First management level It shall ensure with its devices all of the management tasks applying to individual technological units of the generating plant as well as remote management of the generating plant from the superior dispatching level. The first level shall include subsystems (parts) performing its functions in relation to respective technological equipment of the generating plant. For the sake of flexibility, autonomy and redundancy, their excessive integration shall be undesirable This includes particularly direct management and primary regulation functions. Systems shall be designed as open-ended. In terms of information exchange, the question of the compatibility of interfaces shall be of importance. Within the first management level, external links and information exchange shall be secured, e.g. for: remote supervisory control from the superior dispatching centre, exchange of process data related to grid observation, work measurement in exchange points, links to co-operating dispatching centres, eventually electric stations, to which power is transmitted. Second management level It shall ensure with its devices all of the central management tasks applying to the generating plant. The aim is to deal with the automated control system (ACS) whose primary task is to create an environment that will provide managers with computer support in planning, operation preparation and assessment activities with a view to optimising electricity and heat generation. 60 7 INFORMATION COLLECTION AND HANDOVER For reliable and safe operation of the transmission system it is necessary to provide required information for operation preparation, real time operation and operation evaluation. Each legal or individual entity, using the transmission system services, e.i. a generation facility (paralleled to the transmission system or to the 110 kV distribution grid), as the distribution grid operator, as a direct electricity consumer from the transmission system and as an electricity trader based on the Slovak territory, shall provide the TSO Dispatching Centre with the data and documentation necessary to prepare operation, operative contorl and Slovak power system operation analysis. The information flow must be fluent and follow the time as well as the term related requirements of the TSO Dispatching Centre. The transmission system operator and user must be adequately and timely informed about any failures on by it operated parts of the power system. 7.1 Operating information 7.1.1 Information from power plants Generator status change: - disconnection, - connection, - testing. Parameters of primary control, secondary control, tertiary regulation, load curves: - values, ranges, speeds, start-up period, conditions. Change of installation availability: - planned repairs, - required activities. Regulation capability change: - primary active power control, - secondary active power control, - tertiary active power regulation, - secondary voltage control, - parameters of the PSS feedback. Hazardous power plant operation. Forced operation. Operation related events. Support services: - primary active power control, - secondary active power control, - tertiary active power regulation, - secondary voltage control, - dispatching reserve, - prompt dispatching reserve. 61 7.1.2 Information from foreign transmission systems Securing the foreign line: - time of disconnection, - time of earthing, - time of deearthing, - time of readiness for switching. Actions of the protections and automatics on the foreign line - protection startup, - opening by the protection, - protection failure, - automatics startup, - automatics action, - automatics failure. Transmission system operation related events: - requirement on topology change, - transmission capacity change. 7.1.3 Information from the distribution system B-form for the equipment linking the transmission and distribution systems: - B-form number, - logbook, - work supervisor, - number of workers, - beginning of work, - end of work, - activity description. Securing the units linking the transmission and distribution systems: - time of disconnection, - time of earthing, - time of deearthing, - time of readiness for switching. Actions of the protection and automatics on the equipment linking the transmission and distribution systems: - protection startup, - opening by the protection, - protection failure, - automatics startup, - automatics action, - automatics failure. Transmission system operation related events: - change of topology, - change of transmission capacity. 62 7.1.4 Information on development of the transmission system and sources new lines installation, new substantion construction, new source construction, technical parameter changes. 7.1.5 Information from the transmission system B-form: - B-form number, - logbook, - work supervisor, - number of workers, - beginning of work, - end of work, - description of activity. Securing the equipment: - time of disconnection, - time of earthing, - time of deearthing, - time of readiness for switching. Protection and automatics actions: - protection startup, - opening by the protection, - protection failure, - automatics startup, - automatics action, - automatics failure. Transmission system operation related events: - loss of voltage, - ecological defects, - fire, - lethal and massive injury. Risk substantion operation: - loss of internal consumption, - unprocured internal demands, - damaged equipment. 7.1.6 Information and documents prepared by the transmission system operator dispatching centre operation report: - annual, - monthly, - weekly, - daily. 63 assumptions of the daily load curves at individual operation preparation phases - yearly preparation, - monthly preparation, - weekly preparation, - daily preparation. Transmission system capacities: - TTC, - ATC, - TRM, - NTC, - NTF. Requirement on support services: - primary active power regulation, - secondary active power regulation, - tertiary active power regulation, - secondary voltage regulation, - dispatching reserve, - prompt dispatching reserve, - operation as an island, - blackout startup. Rules for support service monitoring: - Primary active power regulation: primary regulation test less than 2 years old, accepted by the TSO Dispatching Centre, finding out the primary regulation time period by the TSO Dispatching Centre; period of the primary regulation shorter than 15 minutes is not considered in terms of the total time; the operation time calculation is carried out based on the primary regulation OFF/ON signal; the signal must be taken out of the process; the TSO Dispatching Centre does not accept a signal generated by the human factor, providing the TSO Dispatching Centre with the active power values involved in the - primary regulation. Secondary active power regulation: secondary regulation test less than 1 year old, accepted by the TSO Dispatching Centre, finding out the secondary regulation time period by the TSO Dispatching Centre; period of the secondary regulation shorter than 15 minutes is not considered in terms of the total time; the operation time calculation is carried out based on the SPC capability signal; the signal must be taken out of the process; the TSO Dispatching Centre does not accept a signal generated by the human factor, providing the TSO Dispatching Centre with the active power values (Pmin, Pmax) - involved in the secondary regulation. Tertiary active power regulation (TPR): identifying the operation time with a possibility of tertiary regulating by the TSO Dispatching Centre; the calculation of operation time with possible tertiary regulation is done based on the TPR capability signal, providing the TSO Dispatching Centre with the active power values (P-, P+) with the possible tertiary regulation. 64 - Dispatching reserve: identification of the dispatching reserve by the TSO Dispatching Centre, - power in the dispatching reserve approved of by the TSO Dispatching Centre. Prompt dispatching reserve: identification of the prompt dispatching reserve by the TSO Dispatching Centre, - power in the prompt dispatching reserve approved of by the TSO Dispatching Centre. Operation as an island: the test of the as-an-island operation less than 10 years old accepted by the TSO Dispatching Centre, - identification of the operation time as an island by the TSO Dispatching Centre. „Blackout“ start: test of the „Blackout“ start less than 10 years old accepted by the TSO Dispatching Centre, identification of the operation time with the blackout start possibility by the TSO Dispatching Centre. Support service evaluation: - Primary active power control: evaluation of MW x minutes of primary control operation per month by the TSO - Dispatching Centre. Secondary active power control: - evaluation of MW x minutes per month by the TSO Dispatching Centre. Tertiary active power control: - evaluation of MW x minutes per month by the TSO Dispatching Centre. Dispatching reserve: - evaluation of MW x minutes per month by the TSO Dispatching Centre. Prompt dispatching reserve: - evaluation of MW x minutes per month by the TSO Dispatching Centre. Operation as an Island: - evaluation of minutes per month by the TSO Dispatching Centre. „Blackout“ start: evaluation of number of blackout starts per month by the TSO Dispatching Centre. Lists of companies and installations for the support services: - primary active power control, - secondary active power control, - tertiary active power regulation, - secondary voltage control, - dispatching reserve, - prompt dispatching reserve, - operation as an Island, - blackout start. 7.2 Failure information Transmission system failures: - power equipment failures, - auxiliary equipment failures, 65 Distribution system failures: - protection and automatics failures. events affecting the transmission system. Generation installation failures: - electric equipment failures, - thermal equipment failures, - protection and automatics failures. 7.3 On-line measurement and signalling It is necessary to on-line transmit some analogue parameter measurement values as well as some unit (contacting units and protections) status signals to the TSO Dispatching Centre. 7.3.1 On-line measurement and signalling from the transmission system Bus-bar: - voltage, frequency, protections, automatics. Overhead line: - active and reactive power, voltage, current, electric energy, breaker, disconnectors, earthing units, protections, automatics. Transformer: - active and reactive power, voltage, secondary side current, transformer tap, oil temperature, winding temperature, electric energy, breakers, disconnectors, earthing units, protections, automatics. Bus-bar section switches: - active and reactive power, current, breaker, disconnectors, earthing units, protections, automatics. Compensation device: - reactive power, current, breaker, disconnector, earthing unit, protections, automatics 7.3.2 On-line measurement and signalling from foreign transmission systems Bus-bars: - voltage. Overhead line: - active and reactive power, - breakers, - disconnectors. Transformer: - active and reactive power, - transformer tap, - breakers, - disconnectors. Compensation device: - reactive power, - breakers, - disconnectors. 66 First foreign substantion: Second foreign substantion: - complete measurement and signalling out of process. - voltage, - active and reactive point balance. The communication is realized by interconnecting the TSO Dispatching Centre ASCS to the respective distribution company ASCS. 7.3.3 On-line measurement and signalling from the distribution system Bus-bars: Overhead lines: - 110 kV voltage in the superior substantion. - active and reactive power, - breakers in the superior substantion, - disconnecters in the superior substantion, - active power of foreign 110 kV lines. Transformers: - active and reactive power, - breakers in the superior substantion, - disconnecters in the superior substantion, Compensation device: - reactive power, - breakers in the superior substantion, - disconnecters in the superior substantion, The communication is realized by interconnecting the TSO Dispatching Centre ASCS to the respective distribution company ASCS. 7.3.4 On-line measurement and signalling from power plants terminal voltage, boundary voltage, terminal active and reactive power, supplied and demanded active and reactive power at the boundary, minimum terminal active power in secondary control, maximum terminal active power in secondary control, minimum terminal reactive power, maximum terminal reactive power, water reservoir levels, instant prompt dispatching reserve, instant turbine and pumping energy, bottom reservoir emptying time, water inlets and outlets, ambient temperature, signalling: - breakers, 67 - disconnectors, - SPC capability, - SPC failure, - SVC capability, - SVC failure, - primary control, - local/remote control. Measurement of electric energy in the transmission system: Measurement of electric energy in foreign transmission system: - supplied and consumed energy at individual points. measurement of electric energy on the point of accounting. Measurement of electric energy in distribution system: Measurement of electric energy at the power plant: - supplied and demanded energy at the points of consumption. - terminal generation, - supplied and demanded energy at the border. Communication between the TSO Dispatching Centre and the power plant must be direct (point-to-point method). 7.4 Requirements for quality of process data and the method of information exchange 7.4.1 Process data quality Connecting unit signalling must be 2 bits, measurements must be carried out with adequate resolution 12, even more bits, signalling of failures and breaker status must be equipped with a time mark with the event origin time differentiated within miliseconds. The time must be unified and synchronized within power industry. 7.4.2 Precautions in data exchange In connections between control systems of the dispatching centres, power plants and electric stations internal transmission paths or stipulated leasings of the public telephone network must be preferentially used. The control systems and telecommunication units must be protected against unauthorized access, to operate the external communication interfaces the programs specifically developed to this purpose, where safety actions can be taken against external unauthorized effects, if there are computer links between dispatching centres, power plants and substantions, then these communications must be directed to a classified communication computer. Thus a system segregation can be reached and unauthorized access to the computers can be prevented from. the measures based on a single protective password are inadequate, no option of unauthorized access to the computerized process control system as well as other computer grids must exist. 68 7.4.3 Compatibility and requirements for transmission paths A significant point of view in data exchange implementation is compatibility and interface between dispatching systems of the respective partners. From the data exchange point of view for real time grid monitoring it is required: standardized form IEC-870-5-101, in case of existing forms it is necessary to assure a gradual transfer to the standardized form, the information transmission must be done by 2 independent paths under minimum speed 2,400 Bd. 7.4.4 Data transmission Measurements, commands, required values and signalling must be transmitted only via the serial port by an agreed form. The data transmission must be spontaneous (exceptionally cyclic in case of low amount of data), by the forms of IEC 870-5-101 class in non-symetric operation. In such a case the centre of one partner poses as subordinate to another partner centre and the connection is the point-to-point type. 7.4.5 Accuracy and cycle of measurement for secondary active power regulation Where new installations are being placed in service or where the existing installations are being replaced with new ones the following parameters must be observed: accuracy: - 0.5 – 1.5 % - 1.0 – 1.5 mHz for frequency measurement; for active power measurement; measurement cycle: - 0.1 - 2 seconds; secondary controller action cycle: a backup instrumentation must be provided for the power and frequency measurement. - 7.5 1 - 2 seconds; Documentation 7.5.1 Operation preparation Yearly, monthly, weekly and daily program of activities at the transmission system, yearly, monthly, weekly and daily program of activities at the distribution system related to the transmission system operation, yearly, monthly, weekly and daily schedule of activities at the power plants. 7.5.2 Operative operation Event logbook, protection and automatics actions, events related to the transmission system operation, realized barter trades. 69 7.5.3 Operation analysis Evaluation of yearly, monthly, weekly and daily operation of the transmission system, evaluation of power plant support services, evaluation of demand charts of the consumers, evaluation of realized barter trades. 7.6 Background papers for grid calculations The data are submitted by the transmission system users at least annually with the instant data update following each important change. The data on foreign transmission systems are acquired based on the relevant information exchange agreements. 7.6.1 Factors of the transmission system Electric parameters of the transmission system components, allowable loading of the individual components, setpoints of the protections and automatics, transmission capability, short-circuit capacities and contributions from the respective supplies. 7.6.2 Factors of foreign transmission systems Electric parameters of the transmission system components, allowable loading of the individual components, short-circuit capacities and contributions from the respective supplies. transmission capability. 7.6.3 Factors of distribution systems Electric parameters of the distribution system components, allowable loading of the individual components in the superior substantion, short-circuit capacities and contributions from the respective supplies to the transmission system, transmission capability of the distribution system between respective nodal systems, topology changes. 7.6.4 Consumption values Active and reactive consumption at respective points in various time curves. 7.6.5 Source parameters Parameters of unit transformers - apparent power, - voltage ratio, - current ratio, - no-load losses, - short-circuit losses, - short-circuit voltage, 70 voltage control. Parameters of synchronous generators: - xd- synchronous reactance at d axis, - x’d – transit reactance at d axis, - x”d- subtransit reactance at d axis, - xq- synchronous reactance at q axis, - x’q- transit reactance at q axis, - x”q- subtransit reactance at q axis, - x1- rotor leakage reactance, - T’d0- transit time factor at d axis, - T”d0- subtransit time factor at d axis, - T’q0- transit time factor at q axis, - T”q0- subtransit time factor at q axis, - H – inertia factor (s) or Tj, - ra - stator resistance. - synchronous generator no-load curve (stator voltage as function of exciting current curve) - no-load exciting current, - P-Q curve, - function and setponit of the stator current limiter, - types of applied generator protections and their setpoints. Exciter parameters: - type of exciter, - amplification and time factor of the exciter, - structure and parameters of the voltage controller, - structure and parameters of the underexcitation boundary controller, - function and setpoints of the rotor current limiter. Parameters of turbine and boiler - structure and parameters of the power controller and the frequency corrector, - block diagram - valve opening curve P = f(opening) Parameters of turbine: - Pmax – maximum power - Pmin – minimum power - R - frequency corrector statics - VM – maximum power increase rate - Vm – maximum power decrease rate - TTURB – turbine time factor - DBf – frequency corrector insensitivity zone Controllers and automatics 7.6.6 Transits Data out of long-term transit contracts. 71 8 REQUIREMENTS FOR TELECOMMUNICATIONS FOR POWER SYSTEM CONTROL Telecommunication system (TS) represents a complicated complex of technical means enabling a reliable transmission of information of every type, necessary to ensure the reliable operation of the power system. Namely the following major information flow paths are concerned: between TSO Dispatching Centre and the electricity distribution licence holder dispatching centres, between TSO Dispatching Centre and the electricity generators, between TSO Dispatching Centre and the dispatching centres of the relevant foreign transmission systems, between respective TSO elements and the transmission system users, between individual transmission system users. Operative control of the telecommunication system is provided by the Telecommunication Dispatching job or by the Accident Service (AS). 8.1 Scope of application The code defines the scope of responsibilities and competencies in the field of telecommunication for AS in providing the activities as regards telecommunication control and the telecommunication assets governing. The scope of responsibilities and competencies as regards the telecommunication for the transmission system is identified by: range of the telecommunication system scope of activities that are defined for the TSO obligations. The scope of the TS is defined as a set of technical means that provide transmission of information of any type. Firefighting systems, radio grids, light current distribution grids and computer grids do not belong to the telecommunication system unless they are part of supervisory and controlling systems of the TS. Technical means making up the TS: transmission grids of synchronous and plesiosynchronous digital hierarchy (SDH and PDH), radio-relay paths of plesiosynchronous digital hierarchy (PDH), optical fibre and metallic cable grids, telephone switchboards, HF links, LF transmission units, transmission units to transmit the protection signals, transmission units for invoicing system, WAN. 72 8.2 Operation and maintenance of the telecommunication system Primarily ensures the operational requirements of the electricity system management on the telecommunication services. Data transmitted for the purposes of the electricity system management to the TSO Dispatching Centre are provided in two independent transmission paths. The equipment for transmission of the data for the real-time management and monitoring of the electricity system of the Slovak republic must ensure transmission rate from 2,400 Bd and concurrently in case of failure on one path it will shift to to another one in automatic. The connection paths for electricity system management purposes to the TSO Dispatching Centre are installed as stationary lines. Provides continuous recording the telephone calls of the dispatcher operator at the dispatching workplaces on all levels. The record must contain also a time reading. Provides retaining the records for a month at least unless a failure or another significant operating event is recorded therein. Provides retaining the records for three months at least if a failure or another significant operating event is recorded therein. In case the failure analysis is not concluded the retaining period lasts until the ultimate resolution. For transmission of the system automatics signal, opening commands and comparative protections there must be available two independent direct connecting paths of point-to-point type. For pulling of the distance protection curves two independent direct connecting paths of the point-to point type are recommended to be used. The wiring of the connecting paths must enable their parallel operation and separate operation of one out of the connecting paths. The single path operation is allowable only in case of the other one failure and follow-up the agreement between the consumer and the TSO. The pulling of the distance protections curves may be operated along one independent direct connecting path of the point-to-point type. Provides the transmission of the information, voice and data for the UCTE and regional TSO group purposes to co-ordinate the Czech, Hungarian and Polish power systems (CENTREL) according to the technical commission recommendations. Provides the operational demands of other telecommunication system users. Provides regular preventive maintenance of the telecommunication installations. Provides detecting and evaluating operation and maintenance quality in the TS. 8.3 TSO concurrence with other organizations The power companies, based on mutual agreement, will provide the TSO with their own unutilized transmission capacities, voice and other services, necessary for the transmission system management purposes according to TSO needs. External users of the telecommunication system of TSO will connect their telecommunication installations and telecommunication grids to the TSO telecommunication system only under observing the recommended telecommunication standards and norms as well as conditions stated in the code following the approval of the TSO. 73 The power companies shall provide the TSO with needed rooms to install the telecommunication technologies necessary for the transmission system management in their own facilities. All the companies shall enable energizing from 230 VAC for the TSO telecommunication technology in their own facilities and will be responsible for availability of their equipment. The TSO hereby must respect the individual provisions for the external personnel access to the respective facility. Other power companies shall operate in the rooms common with the TSO telecommunication technology in a way that will not challenge their performance. All the companies in the facilities where the TSO telecommunication technology is situated shall ensure, in an operative way, a permanent opportunity for the TSO personnel to enter their own facilities in order to carry out inspections, assembly, emergency actions on the TSO telecommunication instrumentation. The power companies will inform each other on their own investments especially in the field of the telecommunication development with a possibility of mutual utilization of new transmission capacities. The TSO may render its free transmission capacities and services also to other power companies. 8.4 Quality requirements the telecommunication equipment interfaces must meet the conditions for connecting according to enforced international standards and guides, compatibility between the telecommunication grids of the individual power-related partners must be ensured, a record on a failure conditions of digital telecommunication transmission systems must contain the time identification information; the time must be unified and synchronized within the TSO, to manage the telecommunication systems the programs specifically developed for this purpose must be used, that prevent from unauthorized access to the systems, for the management purposes only classified computer systems on specialized workplaces may serve. 8.5 Safety requirements the connections between dispatching centres (power and telecommunication) are realized only as stationary links, safeguard system must use multilevel system of access passwords, it is necessary to prevent from access of unauthorized personnel to process equipment of the telecommunication system. 74 FINAL PROVISIONS The Slovak Transmission System Code has been approved by the Office for Regulation of Network Industries by its letter no. 1905/URSO/02/09 of 21/08/02. The Slovak Transmission System Code will come in force on 01/09/2002 and is published on the web site of the Slovenská elektrizačná prenosová sústava, a.s. Bratislava ( www.sepsas.sk ). The Transmission System Code is prepared by the TSO and represents the minimum requirements for connecting to the Slovak transmission system and is obligatory for all authorized users of the transmission system. The TSO is anytime entitled to ask the system users for evidence of observing the rules provided in the code. 75 ANNEX 1. RELATED LEGISLATION Act no. 276/2001 Coll. The Act on regulation in grid industries and on alteration and amendment to some acts. Act no. 70/1998 Coll. The Act on power engineering and on alteration to the act no. 455/1991 Coll. on trading (trading act) pursuant to later procedures. Act no. 130/1998 Coll. The Act on peaceful use of nuclear energy and on alteration and amendment to the Act no. 174/1968 Coll. on state supervision of labour safety as amended by the Act of the National Council of the Slovak Republic no. 256/1994 Coll. Act no. 195/2000 Coll. The Act on telecommunications as amended by follow-up directives. Act no. 445/1991 Coll. The Act on trading (trading act) as amended by follow-up directives. Act no. 18/1996 Coll. The Act on pricing as amended by follow-up directives. Act no. 513/1991 Coll. The Commercial code as amended by follow-up directives. Act no. 40/1964 Coll. The Civil code as amended by follow-up directives. Act no. 136/2001 Coll. The Act on economic competition protection and on alteration and amendment to the Act of the Slovak National Council no. 347/1990 Coll. on organization of departments and other national administration authorities of the Slovak Republic as amended by follow-up directives. Act no. 634/1992 Coll. The Act on consumer protection as amended by follow-up directives. Act no. 330/1996 Coll. The Act of the National council of the Slovak Republic on state supervision of labour safety as amended by follow-up directives. Act no. 547/1990 Coll. The Act on specific goods and technology management and inspection. Act no. 126/1985 Coll. The Act on fire protection as amended by follow-up directives. Act no. 127/1994 Coll. The Act of the National Council of the Slovak Republic on environmental impact assessment as amended by follow-up directives. Act no. 52/1998 Coll. The Act on personal data protection at information systems as amended by follow-up directives. Act no. 241/2001 Coll. The Act of the National Council of the Slovak Republic on secrecy protection and on alteration and amendment to some acts. Act no. 175/1999 Coll. The Act on some measures related to significant investment preparation and on amendment to some acts. Act no. 142/2000 Coll. The Act on metrology and on alteration and amendment to some acts. Decree of the Ministry of Economy no. 180/2000 Coll. The Decree of the Ministry of Economy that establishes details on measures under state of emergency in power engineering. Decree of the Ministry of Economy no. 366/1998 Coll. The Decree of the Ministry of Economy that specifies the details on qualification requirements, education and scope of the job capability testing, setting up and performance of the examination commissions as well as on certificates for power engineering business. 76 Decree no. 367/1998 Coll. The Decree of the Ministry of Economy that establishes details on requisites of the application for granting the power engineering business licence. Decree of the Ministry of Economy no. 368/1998 Coll. The Decree of the Ministry of Economy that establishes details on scope of data, procedure for their publishing and on a way of data inspections to execute the state management in power industries. Decree of the Ministry of Economy no. 14/1999 Coll. The Decree of the Ministry of Economy that establishes headquarters and territorial activity of the regional inspectorates of the National power inspection. Decree of the Ministry of Economy no. 267/1999 Coll. The Decree of the Ministry of Economy that establishes details on some terms and conditions of electricity supply and the method of damage calculation caused to the electricity supplier by unauthorized electricity take-off. Decree of the Ministry of Economy no. 15/1998 Coll. The Decree of the Ministry of Economy on terms and conditions of granting the regulatory permit to import and export goods and services in current statement. Decree of the Ministry of Interior no. 17/1994 Coll. The Decree of the Ministry of Interior on exemption of goods from import duty as amended by followup directives. Decree of the Ministry of Interior no. 288/2000 Coll. The Decree of the Ministry of Interior that establishes technical requirements on fire safety in construction and use of the civil structures. Decree of the Slovak Labour Safety Bureau and the Slovak Mining Bureau no. 111/1975 Coll. The Decree of the Slovak Labour Safety Bureau and the Slovak Mining Bureau on filing and registration of work injuries and on reporting the operational accidents and failures of technical equipment as amended by follow-up directives. Decree of the Slovak Labour Safety Bureau no. 74/1996 Coll. The Decree of the Slovak Labour Safety Bureau on operational safety and health protection, safe pressure, lifting, electrical and gas technical equipment and on professional ability. Decree of the Ministry of Interior no. 129/1997 Coll. The Decree of the Ministry of Interior thereby is executed the Act of the National Council of the Slovak Republic no. 100/1996 Coll. on protection of state secret, official secret, on cipher protection of information and on alteration and amendment to the Criminal Act. Decree of the Ministry of Interior no. 297/1994 Coll. The Decree of the Ministry of Interior on building and technical requirements on constructions and on technical conditions of installations with regard to the civil defense requirements as amended by follow-up directives. Notification of the Ministry of Foreign Affairs no. 175/2000 Coll. The Notification of the Ministry of Foreign Affairs on conclusion of the Energy Charter Treaty. Notification of the Ministry of Foreign Affairs no. 176/2000 Coll. The Notification of the Ministry of Foreign Affairs on conclusion of Energy Charter Protocol to power efficiency and associated environmental aspects. Decree of the Slovak Government no. 392/1999 Coll. The Decree of the Slovak Government that establishes details on technical requirements and procedures of compliance assessment for electrical equipment that is used in a specific voltage range. Resolution no. 1905/ÚRSO/02/11 of the Office for regulation of network industries The ÚRSO‘s decision has approved a Dispatching Order to manage the Slovak Power System. Enforced since 1 September 2002. 77 ANNEX 2. QUALITY OF ELECTRICITY SUPPLIED FROM THE TRANSMISSION SYSTEM The electricity in shape that it is supplied to the clients has more variable parameters that affect its usefulness for the client. With regard to use of the electricity it is desirable so that the supplied voltage has constant frequency, undistorted sinusoidal curve and stabilized value. In practice there are several circumstance that cause deviations from the ideal status. Some of the impairing factors arise due to necessary transients in the supply system itself e.g. failures, switching processes, atmospheric phenomena etc. Some other result from various ways of electricity use when a consumer may vice versa affect the voltage in the transmission system. In such cases the consumer is a significant partner that together with the supplier must make his best effort to maintain quality of the electric energy. Qualitative parameters of the supplied electricity are set up by means of selected operating parameters under normal operating conditions, in compliance with the UCTE, STN EN 50160 and PNE 33-01/2000 standard. The characteristics below does not apply to: failure management operations, temporary operational connections in the transmission system during planned activities (maintenance, construction etc.) state of emergency. Network frequency Rated frequency of the supply voltage is 50 Hz. Under normal operations the mean value of the basic frequency measured in 10 second interval for the systems with synchronous connection to the mutually interconnected system must be within 49.5 to 50.5 Hz during 95% week (any seven following days) and within 47.0 to 52.0 Hz during 100 % week. Supply voltage value The supply voltage value for the client is defined for the common supply point. Under normal operations that excludes interruption of voltage, 95% of ten-minutes root-mean-square values of supply voltage must be within the range of 110 kV ± 10 %; 220 kV ± 10 %; 400 kV ± 5 % during a week. Content of harmonics Under normal operations 95% of ten-minutes root-mean-square values of voltage of each harmonic must be within the range according to the table below during a week. A total harmonic distortion factor (THD) must not exceed 3% value. Odd harmonic (not multiple of 3) 5 7 Value (%) 2.0 2.0 Odd harmonic (multiple of 3) 3 9 78 Value (%) Even harmonic Value (%) 2.0 1.0 2 4 1.5 1.0 11 13 17 19 23 25 25 1.5 1.0 1.0 1.0 0.7 0.7 0.2+0.5.(25/h) 15 21 21 0.3 0.2 0.2 6 8 10 12 12 0.5 0.4 0.4 0.2 0.2 Non-symmetry of supply voltage Under normal operations 95% of ten-minutes root-mean-square values of negative phasesequence of supply voltage must be lower than 2% of positive phase-sequence during a week. Value of control signals from the consumers` grid Under normal operations the mean voltage value of the control signal measured for three second period anytime throughout a day must be less than 0.3 % UN in 99% cases. Rapid voltage changes Under normal operations the rapid voltage changes will not exceed 4 % U N but changes up to 6 % UN for a short time may occur. ANNEX 3. INSTRUMENTATION REQUIREMENTS Instrument transformers A class of accuracy for the instrument current transformer (ICT) and the instrument voltage transformer (IVT). 0.2 % for system clearance and management, 0.5 % for informative measurement, 5P20 for protection ICT, 3P for protection IVT. Secondary outputs: ICT - 1 (5) A, IVT - 100, 100/ 3 , 100/3 V. AC parameter measurement converters Converters of P,Q,U,I,f with analogue output: 79 basic accuracy < 0.5 %, input 3 x 100 V line (phase-to-neutral) 3 x 1 A (5 A), imp/current (e.g. electrometer) output + 5 mA, 4-20 mA or + 20 mA, max load 3 to 5 kΩ by the type power supply 220V/50Hz. Compound converters of P,Q,U,I,f: basic accuracy input < 0,5 %, 3x100 V line or phase, 3x1 A,(5 A), output serial communication, IEC form, 870-5-103(VDEW), CAN Profibus, power supply 24 VDC. Analogue instrument inputs of computer channels basic accuracy < 0.2 %, resolution > 12 bit, interference oppression > 60dB/50Hz. Signalling For signal transmission and processing in one direction or command in reverse direction of a string: process – controlled facility CIS – transmission – SLDC ASCS (the time period from process contact closing to signal indication on a screen) <5s While the reaction time of the controlled facility CIS (the time period from process contact closing to the moment of telegram emission onto the communication line) << 1 s Analogous reaction time of the SLDC ASCS system (the time period from the moment of command emission on the screen to the moment of telegram emission onto the communication line) << 1 s Remote active power and voltage control Secondary active power control 80 Criteria for secondary control measurement curves: Measurement accuracy: power <1.5 % for individual power measurements – three-phase frequency <1.5 mHz for reference frequency to control f and P and primary regulation, repetitive measurement frequency < 1 Hz, grid controller cycle period < 2 s. Secondary and tertiary voltage control Measurement accuracy: <1.5 % for individual measurements of P, Q, - three-phase, 0.5 % for Ug measurement, <0.35 % for UN, repetitive measurement frequency < 0.5 Hz, group controller cycle period < 10 s. Instrumentation calibration The basic regulations that principally manage and affect calibration and recalibration of electric parameter meters are as follows: Act 142/2000 Coll. on metrology ISO 100012-1 Metrological confirmation system IEC 51-9 Standard (ammeters, voltmeters, wattmeters), Testing methodology, PNU 2116.1 Digital instruments, TPN 4.11.1-001 Metrological parameter monitoring – digital instruments, TPN 4.11.1-002 Metrological parameter monitoring – analogue instruments. ANNEX 4. FREQUENCY PLAN The frequency plan currently enforced in the Slovak Power System. In case of drop of frequency to: 49.8 Hz - „lowered frequency“ signal realized in all important power engineering facilities - automatic disconnection from central controller of P, f a U - automatic increase in power of all thermal power plants - manual increase in power of nuclear power plants - automatic shift of hydroelectric power plants to speed control 81 - automatic disconnection of Čierny Váh pumped-storage plant from pumping - identification and release of extremely loaded system elements 49.6 Hz – automatic disconnection of other pumped-storage plants from pumping – gradual connecting the pumped-storage plants to turbine operation mode 49.0 Hz – degree 1 of automatic frequency unloading of 13.5% quantity 48.7 Hz - degree 2 of automatic frequency unloading of 12.5% quantity 48.4 Hz - degree 3 of automatic frequency unloading of 12.5% quantity 48.1 Hz - degree 4 of automatic frequency unloading of 14.8% quantity 48.0 Hz – automatic disconnection of Košice heating plant and its shift to self consumption 47.5 Hz – automatic disconnection of all power plants and their shift to self consumption In case of increase in frequency to: 50.2 Hz - „increased frequency“ signal realized in all important power engineering facilities - automatic disconnection from central controller of P, f a U - automatic decrease in power of all thermal power plants - manual decrease in power of nuclear power plants - automatic shift of hydroelectric power plants to speed control - automatic disconnection of Čierny Váh pumped-storage plant from turbine mode - identification and release of extremely loaded system elements 50.4 Hz - automatic shutdown of other pumped-storage plants from turbine mode - gradual connecting the pumped storage plants for pumping 51.0 Hz – automatic disconnection of nuclear power plants and their shift to self consumption - automatic disconnection of Košice heating plant and its shift to self consumption 52 Hz - automatic disconnection of Bratislava combined cycle plant to self consumption 53.0 Hz – automatic disconnection of all power plants to self consumption 82 ANNEX 5. GLOSSARY 5.1. Accidental operation Accidental operation has following features: 5.2. Alarm condition The alarm condition is such a system status when all parameter values are in allowable limits but n-1 criterion is not met. 5.3. Appliances The appliances are the devices and equipment that uses the electric energy and convert it into other forms of useful energy. 5.4. Automatic re-switching The Automatic re-switching is short power supply shutdown effective for the instances when a failure has developed on the transport equipment that cause could be recovered by short opening the electric circuit (e.g. arch). If the failure lost, its successful re-switching. If the failure did not disappear, the equipment is ultimately switched off and this is the unsuccessful re-switching. We recognize single-phase and three-phase re-switching. 5.5. Automatic frequency load sheding The Automatic frequency load sheding is an automatic disconnection of consumers by means of frequency relays. 5.6. Automatic power control Automatic power control is a set of technical and programmable means to real-time manage the active power of the power plant units (free of operator action). 5.7. Automatic supervisory control system Automatic supervisory control system is a set of technical and programmable means to real-time control the power system operation. 5.8. Authorized client Authorized client is an electricity client that is legally authorized to conclude a contract on electricity supply/take-off with any supplier. 83 5.9. Available transmission capacity (ATC) The available transmission capacity is a free transmission capability that remains between the two interconnected regions for further business beyond the technical assurance of already contracted transmission liabilities. 5.10. Blackout startup The blackout startup is the ability to resume generation capacity and supply of the electricity from the deenergized conditions following the complete system breakdown. The electricity generation will start with the generators able to start up without the grid voltage that will back up additional generators. The islands made up in this way will be gradually mutually interconnected or tied to the consistent grid. 5.11. Calculation model of the power system The calculation model of the power system is a tool to analyze the transmission system modes. 5.12. Circle flow The circle flow of electricity is such a flow that is closed through neighbouring regulation regions. It corresponds to the flow of load measured on interconnecting lines between the regulation regions as a difference between real energy exchange and agreed schedule of the exchange. It arises if the power balances of individual regulation regions (natural circle flow) are poised and the supply schedules for the transport distribution are agreed on in compliance with non-homogeneous allocation of impedances, connections and loadings. 5.13. Client’s equipment The client’s equipment is the technical equipment of the system users. 5.14. Close area The close area comprises the system area of other operators neighbouring with the operator’s area. The topological changes to the close area considerably affect the calculation accuracy. 5.15. Connecting link The connecting link is a point of connection between the TSO grid and the client’s facility. Usually it is situated on a breaker between the grid that serves for the public supply and equipment directly defined for the system user. Respective details must be specified in contracts on the supply connection. The connections between respective TSO are established in the bilateral agreements. 5.16. Cold, warm, hot shutdown standby Cold, warm, hot shutdown standby is a part of the operational reserve that consists of summary of capacities of power plant units ready to start up at the defined time. 84 5.17. Common mode failure The common mode failure is concurrently affecting failure at multiple installations (grid equipment and generation units). 5.18. Conditions for connection to transmission system The conditions for connection to the transmission system are the conditions that must be met to connect the applicant for the transmission system use. 5.19. Connection to the transmission system Connection to the transmission system means connecting the user’s equipment to the transmission system once the technical and commercial terms and conditions have been met. 5.20. Continuous assurance of active power reserve Continuous assurance of active power reserve is assurance of standby power beyond the time period of performance of standby power actuated for frequency stability purposes. 5.21. Control block The control block comprises one or more regulations regions which power control action is coordinated with regard to other control blocks that operate in the system. The control block has to provide implementation of the final schedule of activities with regard to other control blocks and must be able to recover frequency under deviations to have caused failures. The control block is not responsible for the primary control, this task is the responsibility of the respective regulation regions. 5.22. Control by the grid features The control by the grid features is such a control in which the balance deviation resolution (arisen due to disequilibrium in the regulation region itself or to activation of the primary control power for other regulation regions) is made by a procedure according to the grid features of the system. According to this principle each controller’s task is decrease the total regulation deviation G i to zero (Gi = Pi + Kri f). 5.23. Co-ordination clearing centres The co-ordination clearing centres are the administrative departments delegated with clearing tasks by the regulation units. Within UCTE the co-ordination centres for clearing are The Regulation centre of RWE Energie AG in Brauweiler and the Regulation centre of Elektrizitäts-Gesellschaft power system in Laufenburg. The Regulation centre of PSE,s.a. power system in Warsaw is the co-ordination centre within CENTREL. 5.24. Compensation means The equipment exclusively designed for generation or consumption of reactive power aimed at voltage control and electricity losses reduction. 85 5.25. Coverage of transmission losses The coverage of transmission losses is compensation of the transmission system losses that are caused by power transmission between the transmission system users and power transits. 5.26. Delta criterion The delta criterion is a significant parameter for data transmission according to a principle of changes („change principle“). According to value and calculation processing we recognize: - static delta criterion (the parameter is send if its value exceeds the setpoint value dependant on lastly sent value), - integral delta criterion (the parameter is sent if its integrated value at set time exceeds setpoint value dependant on lastly sent value). The delta criterion is usually set by degrees (e.g. 10%, 5%, 3%, 1%, 0%) out of the transmission range of the parameter. If the measured value is transmitted via telegram in a physical value format (figure, float) then the delta criterion is stated in absolute value out of the measurement range. 5.27. Dispatching reserve The dispatching reserve is electrical power must be available to the TSO Dispatching Centre in case of unforeseen lack of power in the power system. Dispatching reserve is especially: rotating (primary, secondary, tertiary) cold shutdown backup (cold shutdown reserve: paralleling within one hour, quick (minute) reserve: paralleling within 15 minutes). 5.28. Directive No. 96/92/EC Directive No. 96/92/EC is the EU guide on common rules for the internal market with the electricity in the membership countries. It was passed by the European Parliament and the Council and is enforced since 1996. 5.29. Distribution system The distribution system is a set of equipment for electricity transport from the transmission system or sources paralleled thereto to consumers within the specified region. Parts of the distribution system are also control, protection, safeguard and information systems. The distribution systems supply electric energy to the ultimate customers using the most appropriate voltage level. 86 5.30. Electric grid The electric grid is a system of individual mutually interconnected electrical stations, overhead lines and cabling designed for electricity transmission and distribution. It serves as a link between generation facilities and consumers. It can be classified by its function, operation mode, voltage or ownership structure. 5.31. Electricity market The electricity market is such market configuration where sale and purchase of electricity are performed. The goal of development is reach higher effectiveness of power industry via the open electricity market that is characterized by undiscriminating approach, transparency and objectiveness. A client will be allowed to choose the electricity supplier in competitive environment. Hence implementation of recommendations under the Directive No. 96/92/EC for the EU membership countries is focused thereon. The electricity market configuration can have a number of variants depending on the way of grid access. The most applied are two ways of grid access, i.e. the single buyer model and agreed access of third parties. The electricity market is conditional on quality of transmission, system and support services. 5.32. Electric output transport The electric output transport is technical and physical process of connecting the electricity generation facilities to one or more supply points and respective take-off from one or more generation points to the transmission system. 5.33. Electric output transport for the thirds The electric output transport for the thirds is a portion of the transport that is not designed for the supplier regulation regions or electricity client. If the capacity transport for the thirds exceeds at least one common state frontier then we talk about the electricity transit. 5.34. Electric power The electric power is a product of voltage and current in view of physics. The electric power has an instant value that can vary as function of time. In power engineering, beside instant value the average power values per certain time period are used (e.g. 1/4 hour, 1/2 hour, 1 hour). The average electric power is then ratio of work A per time period T. P= A T 5.35. Electricity client The electricity client is an individual or legal entity that purchases electricity. 87 5.36. Electricity distribution Electricity distribution is the electricity transport within the physically and technically defined region for a consumer’s equipments. It usually utilizes ultra high, high and low voltage grid. 5.37. Electricity exchange between regulation regions Electricity exchange between regulation regions is transport of electricity that flows from one or multiple regulation region points while taken off at one or multiple points of other regulation regions. 5.38. Electricity export Electricity export designates the electricity quantity that was exported from the power system concerned to the surrounding system at the time period. It is divided into planned, unplanned and spot export. The planned export is the electricity export that is executed contractually. The unplanned export is export that is created by deviations of the actually executed export from the planned export. The spot export is operatively agreed export on the spot market. 5.39. Electricity generation licence holder The electricity generation licence holder is an entity that was granted a business licence in the field of electricity generation by an authority in compliance with the Act on power engineering. 5.40. Electricity meter The electricity meter is a device that based on voltage and current values will identify quantity of active or reactive electric energy. The energy amounts are quantified as analogue or digital value. Some electricity meters can indicate also direction of the power flow and provide average values in defined time intervals, eventually store them in memory or send them to remote processing. 5.41. Electricity generator The electricity generator is an individual or legal entity that operate the generation unit. 5.42. Electricity source The electricity source is equipment, a machine or a device where some different kind of energy is converted to electric energy. 5.43. Electricity system grid → electrical grid 5.44. Electricity trader The electricity trader is a legal entity or individual holding the licence to trade electricity. 88 5.45. Electricity trade schedule The electricity trade schedule is required trade of electric energy between the regulation regions. It contains power and time-related parameters in the specified region of electricity supply/takeoff management. 5.46. Electricity transit Electricity transit is transport of electricity from the exporting system to the importing system through one or multiple transmission systems. 5.47. Entity Entity means legal entities or individuals that are the holders of the licence to generate electricity, holders of the licence to distribute electricity, authorized clients and electricity traders. 5.48. Failure The failure is an undesirable shift to inoperable condition or damage due to component (grid element, power generation unit) break. 5.49. Flicker The flicker is undesirable and unallowable oscillation of voltage that results in electric bulb blinking. 5.50. Follow-up cutting-off The follow-up cutting-off is a procedure whereby a failure is recovered from by disconnection of affected installation by a protection with consequent cascade cutting-off of elements. 5.51. Forced operation The forced operation is power plant unit operation necessary because of process, grid or other reasons. 5.52. Frequency collapse The frequency collapse is accidental condition of the power system that arises in case there are no adequate control capabilities in the system to regulate the active power in order to assure power balance between generation and consumption. It will arise when the system does not have enough active power to to assure power balance between generation and consumption. It can develop suddenly, e.g. in transfer of a part of the power system to as an island operation mode with inadequate power (the island sources can not satisfy the consumption demands). The cause of the frequency collapse can be insufficient capacity of sources but also failure of the regulation system/process to release adequate power. Hence, the power plant units are equipped with the island operation controllers that can release the entire regulation range of unit capacity, if necessary. The consequence of the frequency collapse is disconnecting the units and follow-up system breakdown. The collapse can be prevented form by effective measures on generation as well as consumption sides. 89 5.53. Frequency plan The frequency plan is set of measures in the power system (on source and consumption sides as well) which goal is restrict occurrence of big system failures of the frequency collapse type and thus maintain the frequency in the range wherein power plant technical equipment and electricity consumer‘s equipment are not challenged. 5.54. Frequency relief The automatic frequency load sheding. 5.55. Frequency stability The frequency stability is characterized by regulating down the frequency deviations due to disequilibrium between generation and consumption (active power control). 5.56. Generation unit The electricity generation unit is a power plant equipment that can be specified according to certain criteria. The generation unit is a power plant with unit configuration, a power plant with common bus, a combined cycle power plant, a hydroelectric power plant machinery or e.g. solar module etc. 5.57. Generation unit self consumption The generation unit self consumption is electricity necessary for operation of the auxiliary and additional equipment of the generation unit (e.g. water treatment, steamgenerator feedwater station, station/service air/fuel supply, fly ash separation from fumes etc.) except unit transformer (generator transformers) losses. It is necessary to distinguish the self consumption during operation one side and during startup/shutdown on the other side. 5.58. Grid protections The grid protections represent the protection system that restricts consequences of damage to the grid and prevents from the failure propagation in case of failure. 5.59. Holidays The holidays are red-letter days identified by the Act of the National Council of the Slovak Republic. 5.60. Import-export balance The import-export balance designates the balancing sum of foreign exchanges of electricity at the period concerned. It is a difference between the total electricity import and the total electricity export at monitored period (month, year etc.). 90 5.61. Independent generator The independent generator is a holder of the licence to generate electricity that is not the electricity transmission/distribution system operator. 5.62. Insensitivity The insensitivity is a parameter range where a controller does not react. The insensitivity is determined by the equipment design ( Insensitivity band, dead band). 5.63. Insensitivity band The insensitivity band (dead band) is an undesirable range where the controller does not work. The dead band depends on design uncertainty of the regulation string. 5.64. Installed capacity of generation unit The installed capacity of the generation unit is represented by its shield reading of active power. 5.65. Installed capacity of the power system The installed capacity of the power system is a result of the active power values of the generation units in the power system. 5.66. Interconneceted systems The interconnected systems represent a system of two or more power systems synchronously interconnected by means of intersystem connections with major advantages of effective use of various types of the electricity sources. 5.67. Interconnected operation The interconnected operation means operation of multiple mutually interconnected systems. 5.68. Interconnecting equipment The interconnecting equipment is a line or transformer that links the neighbouring transmission systems. 5.69. Interconnection node to the system The interconnection node to the system is a point where the user is connected to the grid. The system user can have the interconnection nodes to the system at one or multiple points of the transmission/distribution system. 5.70. Interruption of the electricity supply Interruption of the electricity supply is unplanned loss of the supply to one or more clients. 91 5.71. Island The island is part of power system electrically separated from the interconnected system. 5.72. Large scale failure The large scale failure is an extensive and severe accident that occurs if there is loss of voltage in the transmission system of the TSO in some number of grids neighbouring system operators in parts of grid of one or more transmission (distribution) systems. 5.73. Limit value violation The limit values are violated if monitored parameters exceed the range boundaries that are established as allowable. 5.74. Loading Loading is a sum of instant power takeoffs from one, multiple or all grids within the regulation region for consumption purpose. 5.75. Loss of source Loss of source is such impairment of source performance that lasts longer than the insensitivity period of the mechanical and engineering system, eventually longer than defined allowable time periods for the calculation conditions where no insensitivity interval is applied (e.g. during repair of broken component). 5.76. Maximum allowable short-circuit current The maximum short-circuit current is the highest allowable short-circuit current in the grid element concerned at defined time. 5.77. Minimum power of the generation unit The minimum power of the generation unit is a value under that its power must not drop under continuous generation. If the minimum power was applied to shorter time period than the continuous operation, it must be highlighted in a certain way. 5.78. Minute reserve (tertiary regulation reserve) The minute reserve (tertiary regulation reserve) is the power that is connected either manually or in automatic in frame of the tertiary regulation – it must be used within 15 minutes. 5.79. Monitored area The monitored area means own region of the grid operator. 92 5.80. (n-1) criterion Capability of the power system to maintain its normal operation condition after loss of one element (line, transformer, unit etc.) while a short-term overloading of installation, voltage fluctuation may occur. 5.81. Neighbouring transmission system The neighbouring transmission system is a system that is directly interconnected with the system concerned. 5.82. Net transmission capability (NTC) The net transmission capability, at the time of identifying, represents the best estimated size of the transport path between the country supplying and the country taking off the electricity. It is especially maximum of permitted exchange of the electricity that does not lead to restrictions to the grid in the interconnected systems. It is a result of the information exchange among the TSO Dispatching Centres in the countries concerned. 5.83. Network access Network access defined by the TS Code is a principle based on that the power plants, clients, traders, distribution entities are able to access to the mutual contracts in a way it will enable them to use the transmission system for their supplies and purchases. 5.84. Network frequency control The grid frequency control is a control procedure thereby the TSO maintains the mutually agreed electrical parameters on the borders of its regulation regions under normal operation and especially under accidental conditions. In accordance with the procedure each TSO will make its best effort to maintain the exchange with other regulation regions within the contractual limits as well as control the system frequency close to the desired value by means of appropriate means and contributions from its own regulation region. 5.85. Network performance calculation The grid performance calculation is a mathematical method to identify level and distribution of power flows and voltage rates in the power system. 5.86. Network safety Network safety in view of “supply assurance“ and „safe system operation“ is the grid capability to perform within the specified time frame with established parameters free of challenging the people health, life or environment. 93 5.87. Normal system condition The normal system condition is its status when all values are at allowable margins and (n-1) criterion is met. 5.88. Normal system operation The normal system operation is the power system operation in a scope of allowable tolerance of required parameters. It has following features: Safe Electricity supply to all clients. All limiting values are kept (e.g. not overloading). (n-1) criterion is observed at all points. Respective power plants and transmission reserves are available. Hazardous (n-1) criterion is not observed at all points. No possibility of self consumption backup at all generation plants and substations. 5.89. Notified transmission flow - NTF is a part of the transmission system that has already been reserved (occupied) due to awarded and confirmed contracts on electricity transport. 5.90. Operating unit P-Q graph The operating unit P-Q graph is a graphic expression of allowable operating status of the power plant unit as the active power function of reactive power while respecting internal and external limitations as well. 5.91. Operation as an island The operation as an island is the operation of some power plants along with part of take-offs that is electrically separated from the interconnected power system. The separated island must have equalized power balance. 5.92. Operation reliability Operation reliability is the system ability to supply the clients while keeping all the technical limits and conditions and considering planned/unplanned outages at defined time. 94 5.93. Operation stability Operation stability is the system ability to maintain the equilibrium status during the normal operations as well as following the transients due to inner impacts, supervisory control and accidental loss of installations. 5.94. Operational safety Operational safety is a system capability to maintain normal operational conditions according to n-1 criterion. 5.95. Partial loading of the generation unit The partial loading of the generation unit is the power value that is somewhere between minimum and maximum permanent capacity of the unit. 5.96. Pilot node The pilot node is a node of the transmission system where the reference voltage is maintained by the secondary control. 5.97. Point of connection to the transmission system The point of connection to the transmission system is a point at which a user is connected to the transmission system. 5.98. Power act The Act of the National Council of the Slovak Republic no. 70/1998 Coll. on power engineering and on alteration to the Act no. 455/1991 Coll. on trading (trading act) pursuant to later procedures. 5.99. Power engineering installation The power engineering installations represent the process complexes designed for generation, transmission, distribution and consumption of electricity. 5.100. Power equilibrium The power equilibrium is the status when generation and planned power exchange with neighbouring systems covers the consumption and losses in the regulation region concerned. 95 5.101. Power installations The power installations represent the process complexes designed for generation, transmission, distribution and consumption of electricity. They are owned by every participant of the electricity market (company or enterprise that supplies electricity to other market participants) as well as a customer purchasing the electricity for its own need. The companies and enterprises that task is general (public) supply of electricity as a secondary function, in this view are considered as public utilities. 5.102. Power number of interconnected system The power number of the interconnected system defines frequency behaviour of the whole interconnected system as well as of the regulation regions. The grid power number u of the interconnected system is a ratio of power change rate Pa and quasistationary frequency change rate f . 5.103. Power plant The power plant is a generator that main task is convert different forms of energy into electric energy. 5.104. Power plant operator The power plant operator is an entity that regulate the plant output with legal power either as an owner or contracted installation and establishes the output schedule. ( The holder of the licence to generate electricity). 5.105. Power plant unit The power plant unit is a generation unit that is capable to independently generate electricity (power plant unit or the whole power plant). 5.106. Power system The power system is a system designed for generation, transmission and distribution of electricity. It represents a functional complex consisting of power plants, electric stations (transformer stations, substations, compensation stations and other stations), electric lains, control, measurement, regulation and protection systems and auxiliary equipment. The main linkage in the power system, that enable fluent handover of electric energy, are electric grids along with information system arranging regulation and management of the system. Up-to-date power system currently represents a highly centralized system with sophisticated management methods. 96 5.107. Power system control The power system control is the activity carried out by the transmission system operator assuring the real-time supervisory control of the power system. It implements the intents established by the operation preparation while concurrently dealing with unforeseen event impact. 5.108. Power system stabilizer The power system stabilizer is a system enabling to improve or mitigate the transients in the system. 5.109. Power unit operation as an island The power unit operation as an island is its synchronous operation in such a part of the power system that has been electrically separated from the interconnected system. 5.110. Primary voltage control The primary voltage control ensures maintaining the stabilized voltage value on the generator terminals. 5.111. Prevention plan against failure propagation The prevention plan against failure propagation is a set of technical and organizational measures ensuring the transmission system safety. 5.112. Primary active power control The primary active power control represent the activities that ensure balance between electricity generation and consumption. It is derived only from the frequency deviations from the desired one. 5.113. Primary control band The primary control band is the primary control power range in the frame of which primary controllers may act in frequency deviation in both directions in automatic. The term „regulation band“ is applicable for every machine, every regulation region as well as for the whole interconnected system. 5.114. Primary regulation band of active power The primary regulation band is the power range of the primary control wherewithin the primary controllers may work in automatic in case of frequency deviation in both directions. The term „primary regulation band“ applicable for machines as well as for regulation regions and interconnected system as well. 97 5.115. Primary regulation reserve of active power The primary regulation reserve of active power is a positive part of the primary control range from the operating point prior to a failure up to maximum regulation output (taking into account limitation). The term „primary regulation reserve“ is applicable for machines as well as for regulation regions and interconnected system as well. 5.116. Public electricity supply The public electricity supply is procurement of (generation and purchase) and offering (transmission, distribution and supply) electricity to power companies for other parties through steady transmission paths. 5.117. Quality of supplied electricity Quality of supplied electricity is a characteristic of the electricity supply that warrants such operational values of the system parameters that are guaranteed by the transmission system operator during normal condition of the power system. The values of the electricity quality parameters do not apply to a failure recovering, temporary operating configurations and states of emergency. 5.118. Reactive power The reactive power is the electric power needed to make up magnetic fields (e.g. in electric motors or transformers) or electric fields (e.g. in condensers). Thus it can have inductive or capacitance nature. 5.119. Real-time data exchange The real-time data exchange is the information flow between the user and the TSO Dispatching Centre important for real-time operation control. 5.120. Reconstructed unit The reconsturcted unit (installation) is refered as the unit (installation) following an extensive reconstruction/upgrade as regards technology by which startup rates (table 6.1) and capacity (table 6.2) are changed. In modification preparation the requirements in the technical conditions are established as for new unit (installation) according to the TS Code. 5.121. Regulation plan The regulation plan defines limitation of power taken off by selected clients at respective regulation grades. 98 5.122. Regulation region The regulation region is the area where the TSO is responsible for the primary power control, secondary power control and the minute power reserve in compliance with UCTE. Each regulation region is physically specified by sites on which the balance monitoring is carried out for central regulation agent within the interconnected system. 5.123. Reliability of transfer to self consumption Reliability of transfer to self consumption is a capability of the generation unit to quickly and reliably transfer to an operating status when it can continue supplying electricity for internal needs or power plant needs, in case of sudden loss of off-site connections. The generation unit must be able to be retied to the grid. 5.124. Remotely controlled unit The remotely controlled unit is a power plant unit that active power is controlled from the transmission system operator`s dispatching centre. 5.125. Renewal of electricity supply Renewal of electricity supply is a result of electricity supply process to the client after accidental interruption. It is ensured by the dispatching control and by the set of technical measures on the side of generation plants and grids. 5.126. Reserve capacity The reserve capacity is the capacity used for correcting the deviations of the power balance to envisaged conditions as compared to the actual conditions or it is the prepared capacity for specific cases to be assumed. 5.127. Restoration plan The restoration plan is a set of technical and organizational measures ensuring placing the system in normal operating condition once it has been completely or partially broken down. 5.128. Re-switching automatics The re-switching automatics is an automatic device that follow-up the breaker opening by the protection action in case of short circuit, will re-switch the breaker after a setpoint time delay (500 – 1,600 ms). 5.129. Rotative reserve The rotative reserve is portion of the operational reserve at power plant units in service and paralleled to the grid up to 15 minutes. 99 5.130. Sale of electricity The sale of electricity is generally understood as commercial supply of electricity. The sale of electricity can be realized between the entities undertaking in the field of power engineering, i.e. generation facilities, distribution facilities and electricity traders and their clients. A supplier is usually obliged to supply electricity with defined quality. The sale of electricity can be done for ultimate consumption or follow-up sale. 5.131. Secondary active power control The secondary active power control ensures observing the agreed balance and frequency. It is derived from the balance and frequency changes and is proportionally integral. 5.132. Secondary control band The secondary control band is the secondary control power range in the frame of which secondary controller may act in automatic in both directions from the operating point of secondary control. 5.133. Secondary regulation band of active power The secondary regulation band is the power band of the secondary control wherewithin the secondary controller can automatically work in both directions from the operating point of the secondary control. 5.134. Secondary regulation reserve of active power The secondary regulation reserve is a positive part of the secondary regulation band from the operating point up to maximum value of the secondary regulation band. A part of the secondary regulation band that is already used is called the secondary control output. 5.135. Secondary voltage control The secondary voltage control ensures maintaining the voltage at selected grid nodes on agreed level. 5.136. Selfgenerator installations The selfgenerator installations are the installations owned by the companies, power plants and people which main business is not the electricity generation for sale but just for self consumption. 5.137. Service reliability Service reliability is the power system ability to perform its transport and supply tasks according to specified conditions at the specified time period. 100 5.138. Short circuit in power plant proximity Short circuit is found close to the power plant if a contribution of at least one synchronous motor to assumed starting surge short-circuit current exceeds twice the rated current of the generator. 5.139. Short-circuit current calculation The short-circuit current calculation is a mathematical method to identify the level of short-circuit currents as function of time. 5.140. Single client The single client is a legal entity responsible for the centralized electricity purchase/sale. 5.141. Stability The stability is the power system ability to maintain synchronous operation of alternators. 5.142. Stability calculation The stability calculation is a mathematical method to verify the stability of operation for selected failures in the power system. 5.143. Stabilized short-circuit current The stabilized short-circuit current is the effective value of short-circuit current remaining once all the transients have been stabilized. 5.144. State of emergency The state of emergency is the state when it is necessary to prevent from accidental loss of component or power plant units by the operation control. 5.145. Supplier An entity supplying electricity to the ultimate customer. 5.146. Supply and take-off nodes The supply and take-off nodes are those nodes in the power system that beside the direct nodes of interconnection of the systems of parties, that supply and take off electricity, include also all supply points between system regions with different voltage levels involved in the third parties approach, that are included in the financial reporting from the service operator point of view. 5.147. Supply connection Supply connection applies to technical connection of the user’s equipment to the transmission system to supply electricity. 101 5.148. Support service provider A transmission system user offering the support services based on the agreement with the transmission system operator. 5.149. Support services The support services represent activities that serve as necessary support to assure the system services of the transmission system. The support services are usually rendered by the transmission system user contractually that are thus involved in system services provided by the transmission system operator. The complete list and definitions of the support services as well as trading rules must be provided in respective documentation. The suppliers of the support services must be certified by an independent institution that is recognized by the transmission system operator. 5.150. Switch failure automatics (SFA) The Switch failure automatics is an automatic device that is actuated in case of breaker failure that should have open by the protection signal within some defined time period. The SFA will send an opening signal to all neighbouring breakers therethrough current is directed to the short circuit. 5.151. System control The system control is a system service that includes all the tasks performed by the TSO as part of co-ordinated obligation of the electricity sources (e.g. for frequency stability) and system control under conditions of national as well as internationally interconnected operation. It is carried out by the national control centres competent for the regions concerned. The system control also includes all the measures to create and maintain prerequisites of measuring and clearing of all services provided. 5.152. System operator The (power) system operator is responsible for safe and reliable operation of the system that belongs to the regulated region as well as for the links to other systems. It also assure rendering the basic system services thus assuring the operation reliability. 102 5.153. System services The system services are activities necessary for reliability, safety and ecology of the system operation as well as for quality of the supplied electricity. The costs on system services assurance are reimbursed by the clients as part of the electricity price. The most significant system services are as follows: Frequency stability. Voltage stability. Supply resume. Safe and ecological system management - frequency and power control, - voltage and reactive power control, - procurement and utilization of capacity reserve of standby, - island operation function following the partial system breakdown, - deenergized status startup following complete system breakdown or its islands, - electricity quality assurance, - carrying out calculations to manage the electricity system. 5.154. Tertiary active power regulation The tertiary active power regulation is manual or automatic shift of the operating points of active power of machines. 5.155. Tertiary voltage control The tertiary voltage control ensures the optimum parameters of the voltage control (voltage level, reactive power generation, transformer voltage ratio, application of compensation components etc.) based on real-time measurement, especially aimed at minimalization of grid losses. 5.156. Third party access The third party access is one of options of the electricity market organization (the other option is a single buyer model). This model of the market allows the producers, authorized suppliers and authorized clients to access to the grid so that they can conclude contracts on electricity supply based on freely negotiated contracts. It is designated by the English acronym TPA. The variants to this model are agreed third party access to the grid (it requires a negotiation with the system operator, designated as regTPA) and controlled access (acronym regTPA). 5.157. Total electricity consumption The total electricity consumption is electricity consumed in regulation area including electricity generated by small producers as well import/export energy balance. 103 5.158. Total transfer capacity (TTC) The total transfer capacity is defined as maximum allowable exchange of generation rate between the two countries that neither leads to restrictions of the grids in both systems nor to threatening the operation safety of the interconnected systems. 5.159. Transients The transients in the system are temporary changes of the system parameters (f, U, I, P, Q,), that occur in the system shift from one stabilized status to another one, e.g. disconnecting, circling, paralleling. 5.160. Transmission capability (TC) The transmission capability is the power set up by calculations that can be transported through the transmission profile without challenging the operation safety while observing the (n-1) criterion. 5.161. Transmission profile The transmission profile is created by the transmission lines inside of the system that identify the system transmission capacity. 5.162. Transmission service recipient The transmission service user is a legal entity or individual that uses the transmission system services. 5.163. Transmission service schedule The transmission service schedule specifies the power value that must be supplied or taken off in certain power system nodes for each hourly duration of contracted transmission service. 5.164. Transmission service supplier The transmission service supplier is a legal entity or individual that regulates transmission, has a right of disposal for the electricity supply at connected nodes and submits the right of disposal to the transmission service recipient as part of a contract on transport and supply. 5.165. Transmission services The transmission services are part of the transmission system services focused on assuring the electricity transport to the transmission system users including trading activities related to the electricity transport for all clients of the mutually interconnected systems. From the technology point of view of the power system operation the system services are a conditional part of the transmission services. The transmission services are usually the regulated part of the electricity market. Electricity market. 104 5.166. Transmission system The transmission system is a complex of power installations with 400 and 220 kV voltage (also the term superior system is applied in the Slovak Republic). The task of the transmission system is rendering the transport and system services including assurance of electricity transport to the subordinate distribution systems and authorized clients. 5.167. Transmission system code A set of public documents specifying the principles for the transmission system operator undertaking, conditions for paralleling and access to its services. 5.168. Transmission system operator (TSO) The transmission system operator is an entity that assures safe and reliable operation of the transmission system and is responsible accordingly. 5.169. Transmission system user The transmission system user is every individual or legal entity that utilizes the grid and that hereto uses also the services of the transmission system operator on contractual basis. 5.170. Transported electricity Transported electricity is the total amount of electricity that enters the transmission system of the power system and is transported via the transmission system. As regards the domestic sources it comprises supply of electricity measured at the power plant boundary, which capacity is directed right to the transmission system and of portion of capacity that is directed to the distribution system 110 kV as well, in such cases where the power is transported to the transmission system via 400/110 kV or 220/110 kV transformers. The electricity import accomplished via the transmission system is physically included in the electricity transported. 5.171. Unit protections The unit protections represent the protection system of the power plant unit against damage and failure propagation to the transmission system. 5.172. Unplanned electricity exchange The unplanned electricity exchange is a difference between the planned electricity exchange value between individual TSO interconnected and exchange realized. 5.173. Voltage collapse The voltage collapse is an accidental status in the power system that arises in case the system does not have adequate regulation capability of reactive power to assure voltage stability in the power system. 105 5.174. Voltage control The voltage control is a process of maintaining the voltage at desired range in the whole system. This is reached by modification of requirements on reactive system power and as regards the clients mainly by using the reactive power compensation components, if necessary. 5.175. Voltage control and reactive power control The voltage control and reactive power control are associated processes wherein the task of the voltage control is maintain the defined voltage in the system pilot nodes by means of the reactive power control. Authors: collective of experts of SE, a.s.; SE, a.s. – PS, o.z.; VÚJE Trnava, a.s. VSE, š.p.; Energosoft, s.r.o.; FEI STU v Bratislave; Prepared by: VÚJE Trnava, a.s. 106
