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REQUIREMENTS FOR CONTROL AND AUTOMATION IN WINDPARKS
Contents
1 Aims and scope............................................................................................................................... 1
2 Definitions ...................................................................................................................................... 1
3 Information to be sent ..................................................................................................................... 1
4 Controls .......................................................................................................................................... 2
5 Protection and automation .............................................................................................................. 3
1 Aims and scope
1.1 The aim of this document is to describe:
1.1.1 the requirements for producers concerning the control and automation of windparks
connecting to the grid;
1.1.2 information that the Producer must send in real time to the Elering Electricity System
Control Centre;
1.1.3 the control functions which the Elering Electricity System Control Centre uses to direct
windparks.
1.2 Fuller and more precise requirements can be given individually when needed for a
connecting windpark as part of the project design for the electrical installations of the
windpark.
1.3 Umbrella document covering this document: PT14 Connection procedures for producers.
2 Definitions
2.1 Producer – electricity company generating electricity from one or more pieces of generation
equipment. The producer in the current context is a generator of electricity that produces or
intends to produce electricity in a windpark connected to the electricity system.
2.2 Connection point – the precisely specified location where the producer’s electrical
installation connects with the grid, which sets the limits of responsibility for Elering and the
client unless otherwise agreed;
2.3 Average voltage – nominal voltage 6-72 kV.
3 Information to be sent
3.1 Requirements apply for each connection point separately.
3.2 The following status signals must be sent in real time from the substation of the windpark to
the Elering Electricity System Control Centre:
3.2.1 110 kV circuit breaker, disconnecting switch, and earthing switch positions where a
producer connects to the grid through a 110 kV line;
3.2.2 circuit breaker, disconnecting switch, and earthing switch positions on the mediumvoltage side of the windpark’s transformer, if the 110 kV unit of the windpark’s
transformer is located in a substation belonging to the TSO, or there is no 110 kV circuit
breaker in the windpark’s substation;
3.2.3 all the outgoing status signals from the circuit breakers of the medium-voltage relay
protection of the windpark’s substation.
3.3 All status signals must be given directly without using relays as double-contact signals.
3.4 The following protection and fault signals must be sent in real time from the substation of
the windpark to the Elering Electricity System Control Centre:
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3.4.1 operation signal of the windpark transformer protection,
3.4.2 fault signal of the transformer protection,
3.5 The following data must be sent in real time from the substation of the windpark to the
Elering Electricity System Control Centre:
3.5.1 the maximum possible active power (MW)
3.5.2 the total nominal active power (MW) of wind turbines under repair,
3.5.3 the total nominal active power (MW) of wind turbines switched off due to over-wind
3.5.4 the voltage and reactive power regulation mode of the windpark (U=const, Q=const).
3.6 The presentation method for the data required in points 3.2-3.5 will be agreed with the
windpark during the approval of the planning for the electrical installations of the windpark.
3.7 The following measurements must be sent in real time from the substation of the windpark
to the Elering Electricity System Control Centre:
3.7.1 the prevailing wind speed at the windpark. The measurement can be given as an
average for the whole park or the wind speed measured at one turbine situated centrally in
the windpark. Only one of these measurements is sent;
3.7.2 the total active and reactive power of the windpark measured at the medium-voltage
side of the windpark’s substation;
3.7.3 the voltage of the medium-voltage busbars in the substation of the windpark and the
voltage of the 110 kV busbars if the windpark has a 110 kV substation (Uab).
3.8 If the 110 kV side of the windpark’s transformer is located in a substation belonging to the
grid, Elering will allow the windpark to link the secondary circuits of its equipment to the
grid substations in the following ways:
3.8.1 For voltages (Uab, Ubc, Uca and 3Uo) in the 110 kV grid switchyard, the supply
border is the terminal box of the related Elering 110 kV transformer. Elering installs
separate circuit breakers there for the windpark.
3.8.2 For the fault and protection signals of the circuit breakers in the 110 kV unit of the
windpark, the supply border is the junction block of that unit’s protection and automation
panel in the Elering control building.
3.9 The control system of the substation of the windpark must have two connections from its
data forwarding board to the main and backup sections of the Elering Electricity System
Control Centre. The protocol used is IEC 60870-5-101.
4 Controls
4.1 The Elering Electricity System Control Centre must be able to control the following
switches:
4.1.1 circuit breaker, disconnecting switch, and earthing switch positions on the mediumvoltage side of the windpark’s transformer, if the 110 kV unit of the windpark’s
transformer is located in a substation belonging to the TSO;
4.1.2 all the circuit breakers of the medium-voltage relay protection of the windpark’s
substation.
4.2 Automatic regulators controlled from the Electricity System Control Centre:
4.2.1 Switching on and off of the automatic regulation mode for voltage and reactive power
(Q=const; U=const);
4.2.2 nominal active power value of 20%-100% of maximum active power with steps of 20
% of nominal active power;
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4.2.3 Q=const mode – reactive power provision from the maximum possible generation of
reactive power to the maximum possible consumption of reactive power in steps of 1
Mvar,
4.2.4 U=const mode – changes in provision of automatic voltage regulation between 110 –
121 kV, in steps of 1 kV. Voltage must be measured in the connection point. The
automatic voltage regulator must be built as part of the control system of the wind turbines.
4.3 Remote control of both active and reactive power must be operational for each connection
point.
4.4 Elering will allow the producer to switch off the windpark’s transformer or lines using the
110 kV power switch in the grid substation.
4.5 The control system of the substation of the windpark must have two connections for data
exchange to Elering’s main and backup electricity system control centres. The protocol used
is IEC 60870-5-101 or IEC 60870-5-104:
4.5.1 IEC 60870-5-101 requires the use of two independent channels of communication. IP
transport is not allowed.
4.5.2 IEC 60870-5-104 requires the use of at least four links. Data connections over a public
data network (including the internet) are permitted only if an encrypted channel is used,
such as a VPN.
4.6 The control system of the windpark’s substation must exchange with Elering’s main and
backup electricity system control centres the information set out in document VT718 with an
accuracy of timing equal to or better than ±1ms.
5 Protection and automation
5.1 The automation mechanisms of the wind turbines must ensure the operation of the 110 kV
lines is not interrupted if the turbines are switched off because of a temporary short circuit
and automatically switched back on. The short circuit can last for a maximum of 1 second
and the subsequent drop out of the voltage can be of up to four seconds.
5.2 Elering builds the backup automatic isolator for the transformer or line unit of the windpark
for rises and falls in frequency. It is set for frequency fall to 46.8 Hz and frequency rise to
50.8 Hz.
5.3 All the circuits needed for controlling and blocking the communications equipment in the
transformer of the windpark must be connected through a control cable from the terminal
box of the windpark’s transformer to the grid substation.
5.4 The protection and control circuits of the windpark’s transformer, which are needed for
switching the transformer off from the 110 kV side, must be connected to the Elering control
building. The supply border is the junction block of that unit’s protection and automation
panel.
5.5 The current needed from the 110 kV unit for the main protection of the windpark’s
transformer can be got by the windpark from the terminal box of that unit.
5.6 Elering does not provide separate current circuits for the backup protection or measurement
on the 110 kV side of the windpark’s transformer. If required, the windpark can install its
own current transformer or use transformers which have a current transformer built into the
110 kV side.
5.7 Elering builds a two-step directed backup current-protection mechanism at the 110 kV part
of the transformer or line of the windpark, which operates with the transformer’s 110 kV
power switches.
Prepared by: Rein Kraav, Hannes Agabus, Mart Landsberg 29.11.2004
Updated by: Igor Dmitrenko 03.02.2011
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