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THE PROGRAMME OF ENTRANCE EXAMINATIONS TO MASTER’S COURSES ON 140400.68 - "POWER AND ELECTRICAL ENGINEERING" FSBEE HPE “DAGHESTAN STATE TECHNICAL UNIVERSITY” IN 2013 The content of the entrance examination Electricity supply systems Overview of power systems of various objects and their characteristics; main types of collectors and modes of their work; calculation methods of the integral characteristics of modes and determining of calculated load values; power consumption modes in supply systems for different purposes; the quality of electricity in power systems; methods of reliability analysis in power systems. Electromagnetic transients Types of short-circuits; common calculation methods, the system of relative units; the equivalent circuit; set three-phase short-circuit modes; transient condition; transitional and sub transient emf and resistance; methods of calculating the transient short circuit; asymmetrical short-circuits; their calculation methods; the use of computers for the calculation of electromagnetic transients processes. Electromechanical transients Static stability of the electrical power system; practical sustainability criteria; method of small vibrations; static stability with the view of the excitation regulators and speed; transients in the load nodes of the system; the stability of load nodes; dynamic stability of the electrical power system; the method of area; processes analysis considering excitation forcing; methods of approximate equation solution of motion of the generator rotor; the concept of the resulting sustainability; process of falling out of generator synchronism; the resynchronization condition. Power systems automation Variety of automatic control systems and their analysis on base of model units; telemechanics systems in the power sector; principles of automatic inclusion of synchronous machines in parallel work; varieties of automatic reclosing; frequency discharge of electrical power systems, automatic voltage and reactive power, frequency and active power control; automatic control of synchronous generators excitation; automatic control of the transformation ratio, regulators of speed turbine frequency; emergency automation, automation of the process of damage determining at power lines. Electrical power systems and networks General information on power systems and electrical networks; the concept of power supply network mode and the problem of network modes calculating; equivalent circuit of electrical networks elements and their parameters; the calculation of the normal and post-emergency modes of electrical networks of various configurations; the power balance in power system; reactive power compensation; regulation of voltage and frequency in the power system; calculation of the power and power losses in the elements of the EPS; the main measures to reduce energy losses; technical and economic basis of the design of electrical networks; the choice of circuit configuration and basic parameters of electrical networks; constructive calculation of overhead lines. Energy supply systems and electric networks The technological process of electricity production at power plants; the main circuits of power stations and substations; the choice of number and capacity of transformers; wiring diagrams; main circuits of heat power plants and transformer substations; auxiliary power supply circuit; the main electrical equipments of power plants and substations; control of frequency and active power; automatic voltage regulation;, electricity quality; reactive power compensation; electrical networks operation modes; operation modes of electrical networks in the energy system; operation mode of neutrals in electrical installations; graphs of electrical loads; basic information on the air and cable power lines design; basic information on construction of cables; the parameters of electrical networks; electrical networks design; electrical networks design; power balance. Electric power engineering Transmission and distribution of power; general information on power systems; AC and DC power lines; step-down and converter substations; characteristics of the equipment of lines and substations; types of configurations of electrical networks; electrical loads of electric networks units; equivalent circuits of lines, transformers and autotransformers; the modes calculations of transmission lines and power networks in normal and post-accident conditions; balance of active and reactive powering in the power system; power quality; voltage and frequency control in the power system; methods of calculation of electric loads; methods of achieving a given level of equipment reliability; power supply systems; the neutrals modes; performance standards of power quality; technical, socioeconomic and environmental requirements for the power supply system. Electromagnetic compatibility in power industry Electromagnetic environment at the electric power facilities; interference sources; easily affected elements; interference channels; interference levels; interference immunity; test and certification methods of secondary circuits elements for interference immunity; the impact of fields generated by electric devices on biological objects; rules on permissible intensity of electric and magnetic fields of industrial frequency for workers and the public; the RF Law on electromagnetic compatibility. Optimization in electric power systems Modes of power and energy systems; characteristics of power plants and their regime possibilities; balances of power and energy and their cover; dispatcher control in power industry; methods of determining of the most optimal regimes most optimal load distribution of the system; load distribution in power system with hydro and thermal power plants; environmental protection and optimum conditions; the optimal allocation of active power in the energy system; types of restrictions on power system optimization mode; forecasting of electricity consumption and power system load graphs; approaches to optimization of energy system development; optimization of the reliability level of power systems; optimum frequency and voltage values. The use of computers in power industry The choice of networking schemes; selection algorithm; the choice of wire and cable section in the networks of different purposes and rated voltages: integration of the reliability factor in the design of electrical networks; basis of normal modes calculating of complex electrical networks; calculations of homogeneous networks. Technical means of dispatching of engineering management Problem and structure of operative-dispatching of power systems; information management framework (communication, information, signal, noise, coding); types and quantitative characteristics of the operative-dispatching information; information transformation; carriers of information, signals as tangible media materials, reliability of information transfer; technical means of collecting, transmission, and display of the operative-dispatching information; evaluation of the quality of information transmission; telemechanics system; microprocessor telecomplexes; teleprocessing system of data; automated power management systems in power industry, features and construction principles of the automated control systems of energy facilities. ENTRANCE EXAMINATION QUESTIONS POWER SUPPLY SYSTEMS 1. Terms and definitions: power system, electric power system, power supply system, independent power supply, the power supply center, MSS (main stepdown substation), DP (distribution point), TS (transformer substation), internal and external power supply. 2. Category of power supply reliability of electrical receivers’ energy by the rules of organization of electrical installations. 3. The concept of individual and group load diagrams. Ratio of form, use, demand, peak load. 4. Methods of calculation of electrical loads. 5. Procedure of calculating the loads by the method of ordered graphs. 6. The neutral modes of power systems voltage above 1 kV. Advantages and disadvantages of different modes neutral. 7. The neutral power systems with voltage up to 1 kV. Advantages and disadvantages of different neutral modes. 8. The concept of number of hours of use of the maximum load and time of maximum losses. 9. Calculation of annual consumption, power loss and electric loss in transmission lines. 10.Calculation of annual consumption, power loss and electric loss in transformers. 11.Technical and economic comparison of options of power supply systems. 12.Power supply circuits requirements. 13.Radial, trunk and hybrid circuits, their variants. Advantages and disadvantages of circuits. 14.Sources and consumers of reactive power. Need of reactive power compensation. 15.Calculation of power of compensating devices. 16.Principles of arrangement of capacitor batteries in the electricity system. 17.Choice of number, structure, power, and the installation place of power transformers in power supply systems ELECTROMAGNETIC TRANSIENTS 1. Synchronous generator, its resistances, the formulae for calculating of active and inductive resistance in the named and relative units for the definition of shortcircuit currents. 2. Power transformer, its resistances, the formulae for calculating of active and inductive resistance in the named and relative units for the definition of shortcircuit currents. 3. Resistance of power lines. Physical explanation. The formulae for calculating of active and inductive resistances for the definition of short-circuit currents. 4. The calculation of current-limiting reactor resistances (single and twin) in the named and relative units for the definition of short-circuit currents. 5. Design model and the equivalent circuit of power grid forming principles. 6. Conversion of equivalent circuits to determine short-circuit currents. 7. What is sub transient, transient and steady state current of the short. 8. What is the short-circuit surge current, and how to calculate it. 9. How to determine the three-phase short circuit current at the terminals of rated voltage (RV) of step-down transformer with power from its infinite power system (resistance of the system is zero). 10.Procedure for calculating the three-phase short-circuit current to choose electric apparatus and live parts. 11.Procedure for calculating the three-phase short-circuit current to select the setting of relay protection. 12.Equivalence rule of the direct sequence. Complex equivalent circuits for asymmetric shorts. 13.The influence of synchronous and asynchronous motors on the shorts currents. 14.A practical procedure for calculating of asymmetric shorts. 15.Impact of ART on transient of synchronous machine. 16.The method of standard curves for calculating of short-circuit currents. ELECTROMECHANICAL TRANSIENTS 1. The concept of static stability of the electrical system. 2. Criteria of load static stability. 3. Load-angle characteristics of synchronous generator, running for a powerful energy system. 4. The concept of dynamic stability of the synchronous generator and its analysis using an area rule. 5. Asynchronous mode of synchronous generator, its danger. AUTOMATICS OF POWER SYSTEM 1. Automatic mode control of electric power facilities. 2. The basic principles of the emergency automation. 3. Modern automatic control devices of power systems modes. 4. Auto reclosing (AR) devices requirements. 5. Purpose, operation and classification of auto reclosing devices (AR). 6. Auto reclosing (AR) of power lines. Application features of AR for the lines with dual feed. 7. Auto reclosing (AR) of power transformers. 8. Purpose, operation and classification of Automatic Load Transfer (ALT) devices. 9. Automatic Load Transfer (ALT) of power transformers. Start controls of minimum voltage in (ALT) circuits. 10.Automatic inclusion of generators for parallel operation. The methods of generators switching, equalizing currents and moments. 11.Automatic inclusion of generators for parallel operation. Automatic devices of exact synchronization. 12.Automatic and semi-automatic devices of generators self-locking. 13.Synchronous generators excitation systems. Purpose and types of automatic excitation control (AEC). Device of fast excitation forcing (FEF). 14.Regulation of reactive power and voltage on the power station strips with the devices of automatic excitation control (AEC). 15.The principles of rotary operating speed and active power control of energy units. 16.Automatic voltage regulation in power networks. RPN control of power transformers. 17.Automatic voltage regulation in power networks. Capacitor batteries controlling. ELECTRIC POWER SYSTEMS AND NETWORKS 1. The structure and key elements of power systems. General characteristics of electrical systems and networks. Basic concepts and definitions. 2. Electrical systems. The main advantages of power system interconnection. Electrical networks and their classification. 3. Nominal electrical networks voltages. Area of the nominal voltage usage. 4. The electrical networks and systems schemes. General principles of electrical networks schemes. Schemes of distribution zones. 5. Schemes of urban and rural power grids. 6. Schemes of industrial plants power grids. 7. Schemes of power grids up to 1000 V. 8. Construction of overhead lines (OL) of power transmission and cable lines (CL) of power transmission. 9. Electrical networks requirements. 10. Equivalent circuits and power lines parameters. 11. Equivalent circuits and parameters of two-winding transformers. 12. Equivalent circuits and parameters of three-winding transformers. 13. Power loss in the lines and transformers. 14. Energy loss in the lines and transformers. 15. Measures to reduce the loss of power and energy in electrical networks. 16. Vector diagram of the power line. Dependencies between voltages and powers of start and end of the power network link. 17. Loss and voltage drop. Vector diagram of power line. 18. Calculations of modes by the transmission end data. Voltage calculation in nodes. Calculation of the power balance. 19. Calculations of mode of unbranched and branched open networks of the same nominal voltage. 20. Calculation of open networks of local importance. Tolerable loss of voltage in local electricity networks. 21. Calculation of open networks mode with several nominal stresses. 22.Taking into account the transformers in the calculation of electricity network mode. 23. The basic equations defining power line mode. Line without a loss. Natural loading mode. 24. Calculating of network with dual feed. Definition of current division point. 25. Calculation of meshed network. The method of loop currents. Method of node voltages. 26. Calculation of voltage regulation at the supply center. Counter voltage regulation. 27. Key economic indicators of electrical networks. Criteria of technical and economic analysis of electric networks. 28. Techno-economic comparison of power options. Method of reduced costs. 29. Choice of lines section on economic reasons. Method of economic current density. Method of economic intervals. 30. Choice of line wires sections and cable cores and by the terms of heating. 31. Choice of power lines section by the acceptable voltage loss. 32. Checking of power lines section by the terms of the crown, mechanical strength and thermal stability. 33. Choice of power and the installation of compensating devices. 34. The choice of transformers by economic reasons and load capacity. Economic operation modes of transformers. 35. Matrix methods for network calculating. Equations of steady state mode. Newton's method 36. Reliability of electricity supply. Reliability indices of electrical networks operation. Quantitative assessment of electricity reliability. 37. Ways of improvement of the electricity supply reliability. Opportunities to increase the reliability under the design of electrical networks. Measures on improving the reliability under the operation of electrical networks. 38. Regulation of frequency and active power in the electrical system. The influence of frequency on the operation of the elements of the electrical system. Quality parameters of frequency. The physical nature of the active power balance and its connection with the frequency control. 39. Control of frequency and active power in the electrical network. Primary frequency control. Secondary frequency control. Principles of automatic frequency control. 40. Frequency control in post-emergency conditions. AFU (automatic frequency unload). Peculiarities of frequency control in associated power systems. 41. Voltage and reactive power control in the power system. Means of control of the voltage and their use principles for the mode control. 42. Means of voltage control. Choice of transformers and autotransformers branches. The concept of regulation. 43. Transformers off-load tap devices. Seasonal voltage regulation. 44. Transformers under load voltage regulation devices. Counter voltage regulation. 45. Choice of compensation devices power by the voltage regulation condition. 46. The aims and objectives of the mechanical calculation of structural elements of power lines. Application areas and operating conditions of overhead and cable power lines. 47. Designed climate conditions. Designed combinations of climatic conditions. Allowable stresses in the wires and cables. 48. Mechanical stresses on wires and cables. 49. Determination of reference conditions for the mechanical calculation of wires. The concept of conditional assembly temperature. 50. The equation of the wire state. Wire calculations in normal modes. Identification of the reference conditions calculation. 51. Sag, overhead line clearance. Mounting curves. ENERGY SUPPLY SYSTEMS AND ELECTRICAL NETWORKS 1. Features of the technological process at the Heat Power Station (HPS). 2. Typical schemes of HPS. 3. A definition of the switch-gear. Dignity and drawbacks of the switch-gear schemes with a single bus system. 4. Scheme of the switch-gear with single-partitioned bus system. Dignity and drawbacks of the scheme. 5. Switch-gear scheme with double bus system. Advantages and disadvantages of the scheme. 6. What switch-gear schemes are mainly used for the district substation? 7. What switch-gear schemes are mainly used for the urban substation? 8. The sequence of operation of the circuit with a separator and short when damaged power transformer disconnection. 9. Design, scope, advantages and disadvantages vacuum switches. 10. Design, scope, advantages and disadvantages of gas-insulated switches. 11. Design, scope, advantages and disadvantages of low-volume oil switches. 12. Selection of switches. 13. Types of power transformers and autotransformers. Transformers cooling systems. 14. Function of switches, disconnectors, load-breaking isolators, shorting devices (SD), separators. 15. Purpose of current transformers (CT), voltage transformers (VT), dischargers, reactors. 16. Heating of live parts in continuous mode. Protractedly valid and rated current of the conductor. Time constant of conductor heat. 17. Heating of live parts in short-term mode. Thermal current pulse of short. 18. Checking of the live parts and devices for thermal stability. 19. Checking of the live parts and devices for electro-dynamic resistance. 20. Checking of switches for breaking capacity. 21. Methods and means of short-circuit currents limiting used in power plants and substations. 22. Power transformers in circuits of power plants and substations. 23. Autotransformers in the circuits of power stations and substations. Operation modes. 24. Modes of electrical neutrals in accordance with the EMP. 25. Voltage regulation in power transformers. 26. Conditions of parallel operation of transformers. 27. Schemes of simplified transformer substations. 28. The scheme of the transformer substation with a partitioned bus system and bypass bus system. 29. The scheme of the transformer substation with double bus system and bypass bus system. POWER INDUSTRY 1. Relay protection as a form of emergency control, its purpose. 2. Basic properties of relay protection: selectivity, speed, sensitivity, reliability. 3. The concept of absolute and relative selectivity. How is provided the selectivity of over current protections? 4. Determination of the main, reserve and additional protections. What is a near and far reservation? 5. Overcurrent protection with independent time lag. The circuit, operation principle. 6. Overcurrent protection with dependent time lag. The circuit, operation principle. 7. Overcurrent protection with starting by voltage. The scheme, operation principle. 8. The choice of actuation data of current cutoff and maximum current protection. 9. Principle and range of longitudinal differential protection of power transformer. 10. Gas relay device. The operation principle of gas protection of transformer. 11. Interconnections of current transformers used for the relay protection and automatics (RPA). 12. Interconnections of current transformers (CT) of the longitudinal differential protection of power transformer. 13. Types of damages, abnormal modes and types of protections of power transformers. 14. Which mode should the longitudinal differential protection of power transformer be built up from? 15. How is the current transformer (CT) for relaying selected? 16. Auxiliary supplies for relay protection systems and automatics (RPA). 17. Design and function of relay DZT-11. ELECTROMAGNETIC COMPATIBILITY IN POWER INDUSTRY 1. Electromagnetic environment at energy facilities. 2. Sources of noise and interference transmission channels. 3. Effect of fields created by electric devices on the biological objects. 4. Russia's law on electromagnetic compatibility. OPTIMIZATION OF THE POWER SYSTEM 1. The task calculation of the distribution of active load between the thermal power stations (TPS). 2. Characteristics of the devices for regulating the network mode by the voltage levels. 3.Optimization of the system with HPS. 4. Network losses. Basic assumptions. 5. Optimization problems. Planning stages of electric power systems. THE USE OF COMPUTERS IN POWER INDUSTRY 1. Structure of calculating algorithms of the steady system operation mode. 2. Equations forming of steady mode of power system. 3. Algorithms for optimization of the system modes. 4. Simplex, method and its modifications. The computational procedure of the method. 5. Calculating algorithms of the static stability of systems. TECHNICAL MEANS OF DISPATCH AND TECHNOLOGICAL CONTROL 1. Features of the technological production and distribution process of energy in power systems. 2. The functions and tasks of the operative-dispatch control. Information management frameworks. 3. Information base as the foundation of modern management technology, information systems, tasks, functions. 4. Computer networks, computer network architecture model. 5. Purpose and types of data transmission protocols in networks. 6. Communication means of computer networks. 7. Technical means for collecting of operational dispatching information. 8. Composition and function of scheduling hardware. 9. Data transmission systems, communication channels with the frequency and time division. 10. Types and parameters of information signals, the characteristic of data transmission channels. 11. Remote control system. Definition, a division by the nature of performing functions, by the type of data transfer. 12. Types of remote control systems, remote control systems by power transmission lines. 13. Remote control systems TM-800, MKT, SMART-KP. 14. Automated control systems in the power industry. 15. Types and forms of ACS, problems solved by ACS at electricity enterprises. 16. SCADA-systems, characteristics, function. 17. OIC-base ASDC, functions and requirements to the OIC.