55986-10_v1_grid code 3 2 5_v 4 1-30 september 2010

8/9/2019 55986-10_v1_Grid Code 3 2 5_v 4 1-30 September 2010

1/74


2/74

Document no. 55986/10, Technical Regulation 3.2.5 2/74

Revision view

Chapter Text Version Date

1 Definition 1.6 adjusted 4.1 30.9.2010

AllUpdated and notified to the Danish Energy RegulatoryAuthority

4.0 29.9.2010

All Public consultation 3.0 16.6.2010

All Consideration by external working group 2.0 1.12.2009

All Compilation of previous regulations 1.0 1.9.2009


3/74


List of contents

1. Terminology and definitions ............................................................. 52. Objective, scope and regulatory provisions....................................... 11

3. Tolerance of frequency and voltage deviations .................................. 17

4. Electricity quality.......................................................................... 23

5. Control and monitoring.................................................................. 34

6. Protection.................................................................................... 47

7. Data communication and exchange of signals ................................... 50

8. Verification and documentation....................................................... 53

Appendix 1 Documentation..................................................................... 55

Appendix 2 Simulation model.................................................................. 66

Appendix 3 Calculation examples for electricity quality................................ 70

Appendix 4 Signal list ............................................................................ 73

Appendix 5 Commissioning report............................................................ 74


4/74


To the reader

This regulation includes the technical and functional minimum requirementswhich wind power plantswith a rated power greater than 11 kW must complywith if they are to be connected to the Danish grid.

The regulation is structured so that chapter 1outlines the terminology anddefinitions used; chapter 2describes the regulatory provisions and relevantreferences, while the technical and functional requirements are described inchapter 3 onwards.

The technical requirements in the regulation are divided in relation to the totalrated powerin the samepoint of connection:

- Wind power plantswith a power output range of 11 kW to 25 kW (typicallycalled 'small wind turbines') - requirements and power limits have beenharmonised with future/existing European and other international standards.

- Wind power plantswith a power output range of 25 kW to 1.5 MW -requirements and power limits are defined in accordance with Danishlegislation, which requires that local development plans be prepared.

- Wind power plantswith a power output range of 1.5 MW to 25 MW -requirements and power limits have been harmonised with other technicalregulations for electricity-generating plants.

- Wind power plantswith a power output greater than 25 MW - requirementsand power limits have been harmonised with other technical regulations forelectricity-generating plants.

The regulation makes extensive use of terminology and definitions, the mostimportant of which are described in chapter 1. In the regulation, terminologyand definitions are written in italics.

The regulation can also be found on our website, and in the event ofdiscrepancies between the English and Danish versions, the Danish version shallapply.

The regulation is published by the transmission system operator(TSO) and canbe downloaded from www.energinet.dk.


5/74

Terminology and definitions


1. Terminology and definitions

1.1 Absolute production limiter

An absolute production constraint is a device controlling active power in relationto an absolute value. A more detailed description can be found in chapter5.2.2.1.

1.2 Plant owner

Theplant owneris the legal owner of the wind power plant. Theplant ownerisentitled to hand over the operational responsibility to a wind turbine generatorsystem operator.

1.3 COMTRADE

COMTRADE(Common Format for Transient Data)is a file format specified inIEEE standard C37.111-1999, which has been developed for the exchange ofinformation on phenomena occurring in connection with faults, testing andsimulation. The standard includes a description of the required file types andthe sources of transient data such as protective relays, fault recorders andsimulation models. The standard also defines sample rates, filters and theconversion of transient data to be exchanged.

1.4 Delta production constraint

A delta production constraint is a device controlling active power with a fixeddeviation (delta) between possible and active power. A more detaileddescription can be found in chapter5.2.2.2.

1.5 Power gradient constraintApower gradient constraint is a device controlling active power with a fixedincrease/reduction (gradient) of the active power. A more detailed descriptioncan be found in chapter 5.2.2.3.

1.6 Electricity supply undertaking

The electricity supply undertakingis the enterprise to whose grid a wind powerplant is connected electrically. For voltage levels up to 100 kV it is the localdistribution network operator, and for voltage levels greater than 100 kV it isthe regional transmission operator.

1.7 Flicker

Flickeris the impression of unsteadiness of visual sensation induced by voltagefluctuations. Flicker occurs if the luminance or the spectral distribution of thelight fluctuates with time. At a certain intensity, flickerbecomes an irritant tothe eye. Flickeris measured by means of a flicker meter in accordance with IEC61000-4-15 [ref. 14].

1.8 Frequency control

The control of active power with a view to stabilising the grid frequency is calledfrequency control. A more detailed description can be found in chapter5.2.1.

1.9 Generator convention

The sign for active/reactive power indicates the power flow seen from thegenerator. The consumption/import of active/reactive power is indicated by


6/74



means of a negative sign, while the generation/export of active/reactive poweris indicated by means of a positive sign.

1.10 Small wind turbine (SWT)

A small wind turbine is one or several wind turbine generator systems with atotal rated power of up to 25 kW which has been connected to thepublicelectricity supply network, see IEC 61400-2 [ref. 13]. A small wind turbineismost often installation connected.

1.11 Public electricity supply network

Thepublic electricity supply network is transmission grids and distributionnetworks whose purpose is to transmit electricity for an indefinite group ofelectricity suppliers and consumers on the terms laid down by public authorities.

The transmission grid is defined as thepublic electricity supply networkwith a

nominal voltagegreater than 100 kV, whereas the distribution network isdefined as thepublic electricity supply networkwith a nominal voltage lowerthan 100 kV.

1.12 Short-circuit power

The short-circuit power, Sk, is the size of the three-phase short-circuit powerinthepoint of connection.

1.13 Point of common coupling

Thepoint of common coupling (PCC)is the point in thepublic electricity supplynetworkwhere consumers are or can be connected. Electrically thepoint ofcommon couplingand thepoint of connectionmay coincide. Thepoint ofcommon couplingis always placed closest to thepublic electricity supplynetwork, see Figure 1 and Figure 2. The electricity supply undertakingdetermines thepoint of common coupling.

1.14 Rated power of a wind turbine generator system

The rated power of a wind turbine generator systemis the highest active powerat which a wind turbine generator systemis designed to continuously supplyelectricity. The rated power can be seen from the type approval, see IEC60050-415-04-03 (modified) and Danish Executive Order no. 651 of 26 June2008) [ref. 21].

1.15 Rated power of a wind power plantThe rated power of a wind power plant,Pn, is the highest active power which awind power plant is approved to supply continuously in thepoint of commoncoupling. The rated powermust appear from the project approval, see IEC60050-415-04-04 (modified) and Danish Executive Order no. 651 of 26 June2008 [ref. 21].

1.16 Rated current

The rated current, In, is defined as the maximum continuous current a windpower plant is designed to provide under normal operating conditions, see IEC61400-21 [ref. 16].


7/74



1.17 Rated wind speed

The rated wind speedis the average wind speed at which a wind turbinegenerator systemachieves its rated power,see IEC 60050-415-03-04 [ref. 28].The average wind speed is calculated as the average value of wind speedsmeasured at hub height over a period of 10 minutes.

1.18 Distribution network operator

Enterprise licensed to operate the distribution network.

1.19 Nominal voltage

The voltage for which a network is defined and to which operationalmeasurements are referred.

1.20 Normal production area

The normal production areaindicates the voltage/frequency level at which a

wind power plantmust be able to continuously produce electricity, see chapter3.1and chapter 3.2.

1.21 Power infrastructure

Thepower infrastructureis the electrical infrastructure between the individualwind turbine generator systemsof a wind power plantup to thepoint ofconnectionwhere the power generated is supplied to thepublic electricitysupply network.

1.22 Balance-responsible party for production (BRP for

production)

A balance-responsible party for production(BRP for production)is financiallyliable to the transmission system operator. The BRP for productionholds thebalance responsibility for a given electricity-generating facility vis--vis thetransmission system operator. It can be seen from Regulation E - Appendix'Guidelines for net settlement of own generation' (Retningslinjer fornettoafregning af egenproduktion)which electricity-generating facilities need aBRP for production [ref. 26].

1.23 Interconnected electricity supply system

The interconnected electricity supply system is thepublic electricity supplynetwork with associated facilities in a large area which are interconnected witha view to joint operation.

1.24 Voltage fluctuation

Voltage fluctuationis a series of rapid voltage changes or a periodic variation ofthe RMS value of the voltage.

1.25 Voltage reference point

A voltage reference pointis a metering point that is used for voltage control.The voltage reference point is either in thepoint of connection or thepoint ofcommon couplingor a point in between. Out of consideration for a possible tapchanger, the voltage reference point is normally found at the high-voltage sideof the plant transformer. The electric supply undertakingchooses the location of

the voltage reference point, see Figure 2.


8/74



The voltage measurement is made available free of charged to the interfacepoint agreed upon if voltage control is required.

1.26 Droop

The droopis the angle of a curve which a control function must comply with.

1.27 Cut-out wind speed

The cut-out wind speedis the maximum wind speed at hub height at which awind power plantis designed to generate power, see IEC 60050-415-03-06.Cut-out-wind speedis calculated as the average value measured at hub heightover a 10-minute period.

1.28 Transmission system operator (TSO)

Enterprise entrusted with the overall responsibility for maintaining security ofsupply and ensuring the efficient utilisation of an interconnected electricity

supply system.

1.29 Point of connection

Thepoint of connection (POC) is the point in thepublic electricity supplynetworkwhere the wind power plantis or can be connected; see Figure 1 andFigure 2for the typical placing of thepoint of connection.

All requirements in this regulation apply to thepoint of connection. Followingagreement with the electricity supply undertaking, reactive compensation at noload can be placed somewhere else in thepublic electricity supply network. Theelectricity supply undertakingdetermines thepoint of connection.

Figure 1 illustrates how a small wind turbineis typically connected to the gridand where thepoint of connection (POC) and thepoint of common coupling aretypically placed. In the situation shown, thepoint of common coupling(PCC)and thepoint of connection(POC) coincide.

Small scale wind power plantscan be connected in the same way as small windturbines.

Figure 1 Typical grid connection of a small wind turbine


9/74



Figure 2illustrates how wind power plantsare typically connected to the gridand where thepoint of connection (POC) and thepoint of common coupling(PCC) are typically placed.

POC

POC

POC

PCCVoltage reference point

Note: if a tap changer has

been implemented,

PCC will normally be the

voltage reference point

PCC: Point of Common Coupling

POC: Point of Connection

Voltage > 1 kV

Consumption

Figure 2 Typical grid connections of wind power plants

1.30 Regional transmission operator

An enterprise licensed to operate the transmission system or an electricitysupply undertaking that operates the transmission system.

1.31 Typical operating voltage

The typical operating voltage, U, is determined by the electricity supplyundertaking. The typical operating voltageis used to determine the normal

production areaand the transformation ratio for the step-up transformer.

1.32 UTC

UTCis an abbreviation of Coordinated Universal Time (Universal Time,Coordinated).

1.33 Wind power plant

A wind power plant is one or several wind turbine generator systems with atotal rated power greater than 25 kW which has been connected to thepublicelectricity supply network, see IEC 61400-1 [ref. 12].

A wind power plantcomprises all necessary power supply and auxiliaryequipment, and it is therefore the entire wind power plantthat must bedesigned in accordance with the requirements in this regulation.


10/74



In this regulation, the term wind power plantis used as the umbrella term forsmall wind turbinesand wind turbine generator systems. A wind power plantonly has onepoint of connection.

1.34 Wind power plant controller

A wind power plant controller is a set of control functions that makes it possibleto control a wind power plant as one plant in thepoint of connection. The set ofcontrol functions must be a part of the wind power plant.

1.35 Wind turbine generator system

A wind turbine generator systemis a system generating electrical power bymeans of wind, see IEC 60050-415-01-02 [ref. 28].

1.36 Wind turbine generator system operator

The wind turbine generator system operatoris the enterprise responsible for the

operation of the wind power plant, either through ownership or contractualobligations.


11/74

Objective, scope and regulatory provisions


2. Objective, scope and regulatory provisions

2.1 Objective

The objective of Technical Regulation TF 3.2.5 is to specify the minimumtechnical and functional requirements which a wind power plantwith a rated

powergreater than 11 kW must comply with in thepoint of connection whenthe wind power plant is connected to thepublic electricity supply network.

In pursuance of section 7(1) of the Danish Executive Order no. 1463 of 19December 2005 on transmission system operation and the use of the electricitytransmission grid etc., this regulation has been prepared following discussionswith the distribution network operators and regional transmission companies. Ithas also been in public consultation before being notified to the Danish EnergyRegulatory Authority.

This regulation applies within the framework of the Danish Electricity SupplyAct, see Danish Executive Order no. 516 of 20 May 2010 as subsequentlyamended.

A wind power plantmust comply with Danish legislation, the Danish HeavyCurrent Regulation and the Joint Regulation (Fllesregulativet). CENELEC andIEC standards apply to areas not governed by Danish legislation.

2.2 Scope

A wind power plantconnected to thepublic electricity supply networkmustthroughout its lifetime comply with the provisions of this regulation.

New w i n d p ow e r p la n t s

This regulation applies to all wind power plants with a rated powergreater than11 kW connected to thepublic electricity supply networkand commissioned on1 December 2010 or later.

Existing w i n d po w e r p la n t s

A wind power plantwith a rated powergreater than 11 kW which wereconnected to thepublic electricity supply networkbefore 1 December 2010must comply with the regulation in force at the time of commissioning.

Changes to existing w i n d p ow e r p la n t s

Existing wind power plantsto which substantial functional modifications aremade must comply with the provisions of this regulation relating to suchchanges. In case of doubt, the transmission system operatordecides whether amodification is substantial.

A substantial modification is one that changes the properties of the wind powerplant, involving the replacement of one or several plant parts. Thedocumentation described in chapter 9 must be updated and forwarded in aversion showing any modifications made.


12/74



2.3 Delimitation

Technical Regulation 3.2.5 is part of the complete set of technical regulationsissued by the transmission system operator, Energinet.dk. The technicalregulations comprise technical rules forplant owners, wind turbine generatorsystem operators and electricity supply undertakings regarding the connectionto and the operation of thepublic electricity supply network.

Together with the market regulations, the technical regulations, including thesystem operation regulations, constitute the set of rules to be complied with by

plant owners, wind turbine generator system operatorsand electricity supplyundertakings.

- Regulation D1 'Settlement metering'- Regulation D2 'Technical requirements for electricity metering'- Regulation E 'Settlement of environmentally friendly electricity generation'- Regulation E (appendix) 'Retningslinjer for nettoafregning af

egenproducenter' (Guidelines for net settlement of autogenerators)- Technical regulation TF 5.8.1 'Metering regulation for system operation

purposes' (Mleforskrift til systemdriftsforml)- Technical regulation TF 3.2.5 'Wind power plants with a power output

greater than 11 kW'

In addition, special rules apply to the granting of compensation in connectionwith downward regulation:

- Regulation E (appendix) 'Compensation for offshore wind farms ordered toperform downward regulation'

The current version is always the versions found at www.energinet.dk.

Operational issues must be agreed betweenplant ownerand electricity supplyundertaking. Any supply of ancillary services must be agreed betweenplantownerand the BRP for production.

This regulation does not deal with the financial aspects of using controlfunctionalities, settlement metering or any technical requirements in thisconnection.

Theplant owneris responsible for safeguarding the wind power plantagainst

possible damaging impacts due to a lack of electricity supply from thepublicelectricity supply networkfor shorter or longer periods of time.

2.4 Statutory authority

The regulation has been issued under the authority of Section 26(1) of theDanish Electricity Supply (Consolidation) Act no. 516 of 20 May 2010 inpursuance of Section 7(1), paras 1, 3 and 4, of the Danish (Consolidation) Actno. 1463 of 19 December 2005 on transmission system operation and the useof the electricity transmission grid etc.


13/74


14/74



2.9 Exemptions and unforeseen events

The transmission system operatormay grant exemption from specificrequirements in this regulation.

An exemption can only be granted if:

- special conditions prevail, for instance of local character- the deviation does not cause appreciable deterioration of the technical

quality and balance of thepublic electricity supply network- the deviation is not inappropriate from a socioeconomic viewpoint.

In order to obtain exemption, a written application must be submitted to theelectricity supply undertaking, indicating which provisions the exemptionconcerns and the reason for the exemption. The electricity supply undertakinghas the right to comment on the application before it is submitted to thetransmission system operator.

If events not foreseen in this regulation occur, the transmission systemoperatormust consult the parties involved with a view to deciding what to do. Ifan agreement cannot be reached, the transmission system operatormustdecide what is to be done. The decision is made on what is equitable, takingwhere possible the views of the parties involved into consideration. Complaintsof the decisions of the transmission system operatorcan be lodged with theDanish Energy Regulatory Authority, see chapter 2.6.

2.10 References

The standards listed are only to be used in relation to the topics mentioned in

connection with the references in this regulation.

2.10.1 Normative references:

1. EN 50160:2009: DS/EN 50160 'Voltage characteristics of electricitysupplied by public distribution networks'.

2. IEC 60038: IEC standard voltages.3. Fllesregulativet2009'Tilslutning af elektriske installationer og

brugsgenstande'.4. Strkstrmsbekendtgrelsen afsnit 6'Elektriske installationer', 2003.

5. Strkstrmsbekendtgrelsen afsnit 2'Udfrelse af elforsyningsanlg',2003.

6. DS/EN 60204-1:Strkstrmsbekendtgrelsen Maskinsikkerhed-Elektriskmateriel p maskiner.

7. DS/EN 60204-11:Maskinsikkerhed-Elektrisk materiel p maskiner-Del 11:

Bestemmelser for HV-maskinel for spndinger over 1000 V a.c. eller 1500

V d.c. og ikke overstiger 36 kV.8. IEC-60870-5-101: Telecontrol equipment and systems, part 5-101.9. IEC-60870-5-104:Telecontrol equipment and systems, part 5-104.

10.IEC TR 61000-3-6: EMC limits. Limitation of emissions of harmonic

currents for equipment connected to medium and high voltage power supplysystems (February 2008).

11.IEC TR 61000-3-7: EMC-limits. Limitation of voltage fluctuations and

flicker for equipment connected to medium and high voltage power supplysystems (February 2008).


15/74



12.IEC 61400-1- Wind Turbines - Part 1: Design requirements.13.IEC 61400-2 - Wind turbines - Part 2: Design requirements for small wind

turbines.14.IEC 61000-4-15: Testing and measurement techniquesSection 15:

Flicker metreFunctional and design specifications.15.IEC 61400-12: Windturbine generator systems. Power performance

measurement techniques.16.IEC 61400-21: Measurement and assessment of power quality

characteristics of grid connected wind turbines.17.IEC 61400-25-1: Communications for monitoring and control of wind

power plants - over all description of principles and models.18.IEC 61400-25-2: Communications for monitoring and control of wind

power plants - information models.19.IEC 61400-25-3: Communications for monitoring and control of wind

power plants - information exchange services.

20.IEC 61400-25-4: Communications for monitoring and control of windpower plants - mapping to communication protocol stacks.

21.BEK nr. 651 af 26. juni 2008: Bekendtgrelse om teknisk godkendelse

for konstruktion, fremstilling, opstilling, vedligeholdelse og service afvindmller.

22.Technical Regulation TF 5.8.1'Mleforskrift til systemdriftsforml'(Metering regulation for system operation purposes)dated: 25 March 2008,

version 1, document no. 9300-08.23.Regulation D1'Settlement metering', dated: December 2008, version 2,

document no. 165903-07.24.Regulation D2'Technical requirements for electricity metering', dateret:

May 2007, version 1, document no. 263352-06.25.Regulation E 'Settlement of environmentally friendly electricity

generation', 2009, July 2009, rev. 1, document no. 255855-06.26.Regulation E - Appendix'Retningslinjer for nettoafregning af

egenproduktion" (Guidelines for net settlement of own production), ver. 1 of

1 July 2010, document no. 27582-10

27.Regulation E - Appendix'Compensation for offshore wind warms ordredto perform downward regulation', ver. 1 of 15 May 2009, document no.15468-09.

2.10.2 Informative references:

28.IEC 60050-415: International Electrotechnical Vocabulary Part 415:Wind turbine generator systems.

29.IEC 60044-1. Instrument transformers Part 1: Current transformers.30.IEC 60044-2. Instrument transformers Part 2: Inductive voltage

transformers.

31.DEFU-rapport RA-557"Maksimal emission af spndingsforstyrrelser fravindkraftvrkerstrre end 11 kW".

32.DEFU-rekommandation nr. 16: Spndingskvalitet i lavspndingsnet, 2.

udgave, juni 2001.

33.DEFU-rekommandation nr. 21: Spndingskvalitet imellemspndingsnet, februar 1995.

34.IEC 62053-21: Electricity metering equipment (ac) Particularrequirements. Part 21: Static meters for active energy.


16/74



35.IEC 60071-1: Insulation co-ordination Part 1: Definitions, principles andrules.

36.IEC 61000-3-12: Limits-Limits for harmonic currents produced byequipment connected to public low-voltage systems with input current > 16

A and 75 A per phase.


17/74

Tolerance of frequency and voltage deviations


3. Tolerance of frequency and voltage deviations

Awind power plant must be able to withstand frequency and voltage deviations

in thepoint of connectionunder normal and abnormal operating conditionswhile reducing the active power as little as possible.

Normal operating conditions and abnormal operating conditions are described inchapter 3.2 and chapter 3.3, respectively.

3.1 Determination of voltage level

Theelectricity supply undertaking determines the voltage level for thewindpower plant within the voltage limits stated in Table 1.

The typical operating voltagediffers from location to location, and the electricitysupply undertakingmust therefore state the typical operating voltage, U, for

thepoint of connection.

The typical operating voltageforms the basis for determining the normalvoltage area U10%.The electricity supply undertaking must ensure that themaximum voltage stated in Table 1 is not exceeded.

If the normal voltage area U is 10% lower than the minimum voltageindicated in Table 1, the requirements for production in the event offrequency/voltage variations must be adjusted so as not to overload the wind

power plant.

Typicaldesignation

Nominalvoltage

Un[kV]

Minimumvoltage

Umin[kV]

Maximumvoltage

Umax[kV]

400 320 420Extra high voltage

(EH) 220 - 245

150 135 170

132 119 145

60 54.0 72.5

High voltage

(HV)

50 45.0 60.0

33 30.0 36.0

30 27.0 36.020 18.0 24.0

15 13.5 17.5

Medium voltage(MV)

10 9.00 12.0

0.69 0.62 0.76Low voltage

(LV) 0.40 0.36 0.44

Table 1 Nominal, minimum and maximum voltage

Maximum (Umax) and minimal (Umin) voltage limits are determined using thestandards EN50160 (10-minute average values) [ref. 1] and IEC60038, tableIII, note 2 [ref. 2].


18/74



The wind power plantmust be able to briefly withstand voltages exceeding themaximum voltages within the required protective functions specified in chapter6.

3.2 Normal operating conditions

It must be possible to continuously start and operate awind power plantwithinthe area designated 'normal production' within the design requirements,restricted only by the settings for over- and undervoltage protection asdescribed in chapter 6.

In the 'normal production' area, the typical operating voltageis U10%, seechapter 3.1, while the frequency area is 49.50 to 50.20 Hz.

Automatic connection of a wind power plant can at the earliest take place threeminutes after the voltage has come to lie within the typical operating voltage

and the frequency lies within 47.00 and 50.20 Hz. The setting of the frequencylimits is determined by the electricity supply undertaking upon commissioning.The requirement for variable frequency limits must be implemented not laterthan 18 months after the commencement date of this technical regulation.

The requirements outlined in the following section are to be consideredminimum requirements.

3.2.1 Wind power plants with a power output range of 11 kW to 25 kW

The overall requirements for active power production which a wind power plantmust comply with in the case of frequency and voltage deviations are illustratedin Figure 3.

N

ORMAL

PRODUCTION

Figure 3 Active power production requirements at frequency/voltage variations

for wind power plants with a power output range of 11 kW to 25 kW

There is no requirement for active power production outside of the normalproduction area.


19/74



The wind power plantmust remain connected to thepublic electricity supplynetworkin accordance with the required settings for protective functions, asspecified in chapter 6.

3.2.2 Wind power plants with a power output range of 25 kW to 1.5 MW

The overall requirements for active power production which a wind power plantmust comply with in case of frequency and voltage deviations are illustrated inFigure 4.

50.0049.5049.0048.5048.0047.5047.00 50.50 51.00 51.50 52.00 52.50

U

point of connection

U +10%

U

U -10%

Frequency [Hz]

Umin

Umax

50.20

80100%o

f

normalproductionforminimum

20seconds

85100%o

f


3minutes

90100%o

f


30minutes 60 -100 % of

normal production for

minimum

15 minutes90

100%

of

nor m

alpro

ductionfor

minimu

m

5hou

rs

NORMAL

PRODUCTION

No req. for production

No req.

for produktion

U +5%

U -5%

Figure 4 Active power production requirements at frequency/voltage variations

for wind power plants with a power output range of 25 kW to 1.5 MW

The wind power plantmust remain connected to thepublic electricity supplynetworkin accordance with the required settings for protective functions, asspecified in chapter 6.

3.2.3 Wind power plants with a power output greater than 1.5 MW

In addition to complying with the requirements in chapter 3.2.2, the wind

power plant must remain connected to thepublic electricity supply networkincase of abnormal operating conditions, as specified in chapter 3.3.

3.3 Abnormal operating conditions

The following requirements apply to wind power plantswith a power outputgreater than 1.5 MW.

The wind power plantmust be designed to withstand sudden phase jumps of upto 20in thepoint of connection without disconnecting or reducing its output.The wind power plant must after a settling period supply normal production not

later than 5 s after the operating conditions in thepoint of connection havereverted to the normal production area.


20/74



The wind power plant must be designed to withstand voltage drops, as shown inFigure 5and supply reactive power as shown in Figure 6 withoutdisconnecting or reducing its output. The wind power plant must after a settlingperiod supply normal production not later than 5 s after the operatingconditions in thepoint of connection have reverted to the normal productionarea.

Irrespective of the requirements outlined in the following chapters, theprotective settings must be as specified in chapter 6.

Documentation to the effect that the wind power plantcomplies with thespecified requirements must be as specified in chapter 8.

3.3.1 Tolerance of voltage dropsIn thepoint of connectiona wind power plantmust be able to withstand voltage

drops down to 20% of the voltage in thepoint of connectionover a period ofminimum 0.5 s (line-to-line voltages for the 50 Hz component) withoutdisconnecting, as shown in Figure 5.

It is allowed to use the voltage measurement for the individual wind turbinegenerator system to perform regulation during voltage drops.

Figure 5 Requirements for tolerance of voltage drops for wind power

plants with a power output greater than 1.5 MW

The following requirements must be complied with in the event of symmetricalas well as asymmetrical faults, ie the requirements apply in case of faults in

one, two or three phases:

- Area A:The wind power plantmust stay connected to the network anduphold normal production.

- Area B:The wind power plantmust stay connected to the network. Thewind power plantmust provide maximum voltage support by supplying a


21/74



controlled amount of reactive power so as to ensure that the wind powerplanthelps to stabilise the voltage within the design framework offered bythe current technology, see Figure 6.

- Area C:Disconnecting the wind power plantis allowed.

If the voltage U reverts to area A during a fault sequence, subsequent voltagedrops will be regarded as a new fault situation, see chapter 3.3.2. If severalsuccessive fault sequences occur within area B and evolve into area C,disconnection is allowed.

In connection with fault sequences in area B, the wind power plantmust have acontrol function capable of controlling the reactive power, as specified in Figure6.

Figure 6 Requirement for reactive power supply, IQ, during voltage dropsfor wind power plants with a power output greater than 1.5 MW

Control must follow Figure 6so that the reactive power follows the controlcharacteristic with a tolerance of 20% after 100 ms.

The supply of reactive power has first priority in area B, while the supply ofactive power has second priority.

If possible, active power must be maintained during voltage drops, but areduction in active power within the wind power plant's design specifications isacceptable, however.

The requirement for control as indicated in Figure 6must be implemented 18months after the commencement date of this technical regulation at the latest.

3.3.2 Recurring faults in the public electricity supply network

The wind power plant and any compensation equipment must stay connectedafter faults have occurred in thepublic electricity supply network, as specified inTable 2.


22/74



The requirements apply in thepoint of connection, but the fault sequence lies ata random place in thepublic electricity supply network.

Based on compliance with the requirements for voltage drops as stated inchapter3.3.1, the requirements in Table 2 must be verified by documentingthat the wind power plant has been designed to withstand recurring faults withthe specifications stated.

Type Fault duration

Three-phase short-circuit Short-circuit for a period of 150 ms

Two-phase short-circuit

with/without earth contact

Short-circuit for a period of 150 ms

followed by new short-circuit 0.5-3 slater, also with a duration of 150 ms

Single-phase short-circuit to earth One-phase earth fault for a period of 150ms followed by a new one-phase earthfault 0.5-3 s later, also with a duration of150 ms.

Table 2 Fault types in the public electricity supply network and their duration

Wind power plant capacitymust be sufficient to comply with the requirementsspecified in Table 2if at least two independent faults of the types specifiedoccur within two minutes.

The energy reserves provided by auxiliary equipment such as emergency supply

equipment, the hydraulic system and the pneumatic system should be sufficientin order for the wind power plantto operate with at least six independent faultsof the types specified in Table 2at 5-minute intervals.


23/74

Electricity quality


4. Electricity quality

4.1 General requirements

When a wind power plant'simpact on the electricity quality is assessed,emissions relating to the following disturbances in thepoint of connectionmustbe documented:

- voltage fluctuations:

o rapid voltage changeso flicker

- high-frequency currents and voltages:

o harmonicso inter-harmonicso disturbances greater than 2 kHz.

Each type of disturbance is specified in the following:

- data basis for calculations- emission limit values- methods for verifying compliance with limit values.

Terminology and calculation methods must in general be in conformity with:

- IEC TR 61000-3-6: EMC limits. Limitation of emissions of harmonic currentsfor equipment connected to medium and high voltage power supplysystems. (February 2008) [ref. 10].

- IEC TR 61000-3-7: EMC-limits. Limitation of voltage fluctuations and flicker

for equipment connected to medium and high voltage power supplysystems. (February 2008) [ref. 11].

- IEC 61400-21: Measurement and assessment of power qualitycharacteristics of grid connected wind turbines [ref. 16].

The electricity supply undertaking is responsible for calculating emission limitvalues and documenting that the limit values for electricity quality in thepointof connectionare not exceeded. The electricity supply undertakingmust agreeon a time schedule for determining emission limit values with parties applyingfor grid connection. If the construction of a wind power planthas been put up

for tender, the emission limit values must appear from the tender material.

Theplant ownermust ensure that the wind power plantis designed,constructed and configured in such a way that the specified emission limitvalues are observed without grid reinforcements being required in excess ofwhat is necessary in order to transfer the energy produced.

4.1.1 Data basisData for the wind power plantas well as thepublic electricity supply networkwill be used in assessing a wind power plant'simpact on the electricity quality.Theplant ownermust provide data for the wind power plantwhile the electricitysupply undertakingmust provide data for thepublic electricity supply network

in thepoint of connection.


24/74

Electricity quality


Theplant ownermust subject each of the type of wind turbine generatorsystemmaking up the wind power plantto type tests performed in accordancewith IEC 61400-21. As a supplement to the type test, theplant ownermayprovide an emission model for the wind turbine generator systemsfor thepurpose of determining high-frequency currents. The result of the type testscan be seen from the type approvals. In general, the rated value of theapparent power Sn,ifor each wind turbine generator system will be used incombination with specific data for the individual types of disturbances.

For wind power plantswith a power output greater than 1.5 MW consisting ofmore than one wind turbine generator system, theplant ownermust alsoprovide a model for thepower infrastructurefor the purpose of determininghigh-frequency voltages.

The electricity supply undertakingmust provide data for thepublic electricity

supply networkin thepoint of connection. For the calculation of voltagefluctuations, see IEC 61400-21, thepublic electricity supply networkcan bedefined by the minimum short-circuit powerSkand the similar grid impedanceangle k, in thepoint of connection.

Where the connection of wind power plantswith a power output greater than1.5 MW is concerned, the electricity supply undertakingmust also provide datafor the frequency dependency of the impedance in thepublic electricity supplynetworkfor the purpose of calculating the emission high-frequency voltages inthe relevant frequency range up to 9 kHz.

4.1.2 Limit values

The electricity supply undertakingis responsible for calculating limit values forthe emission of the various types of disturbances coming from the wind power

plant in thepoint of connectionso as to ensure that the limit values forelectricity quality in thepublic electricity supply networkare not exceeded.

The limit values specified in this regulation have been determined on the basisof the recommendations in IEC 61000-3-6 and IEC 61000-3-7. As regards wind

power plantswith a power output greater than 1.5 MW and apoint ofconnectionfar away from thepoint of common coupling, the electricity supplyundertakingcan normally authorise emissions in thepoint of connectionhigherthan the limit values applying in thepoint of common coupling. Appendix 3

includes examples of the calculation of limit values for the wind power plant.

As regards wind power plantswith a power output lower than 1.5 MW, specifiedlimit values for the wind power plant's emission of high-frequency currents inthepoint of connectionare used. As regards wind power plantswith a poweroutput greater than 1.5 MW, the electricity supply undertakingmust calculatelimit values for the wind power plant's emission of high-frequency currents inthepoint of connection.

4.1.3 Verification

Theplant owneris responsible for verifying that the wind power plantobservesthe defined emission limit values in thepoint of connection. The electricity

supply undertakingmust approve the verification performed by theplant owner.


25/74

Electricity quality


Such verification must be performed in accordance with the methods specifiedin IEC 61400-21 for verifying electricity quality.

Alternatively, theplant ownermay use an emission model to verify thatemission limit values for high-frequency disturbances are observed. In suchcase, theplant owner must validate the emission model within the frequencygroups in which the model is used to verify each of the types of wind turbinegenerator systemsthat form part of the wind power plant. An emission modelhas been validated for a frequency group if it determines current emissionsfrom the wind turbine generator systemso as to ensure that it does not deviatefrom the type test by more than 0.4% of the rated current, equivalent to thetolerance at which high-frequency currents are measured for the individualfrequency groups in accordance with IEC 61400-21.

Verifying that the wind power plantobserves limit values for high-frequency

currents is done by means of methods indicated for the individual types ofdisturbances for aggregating contributions from the wind turbine generatorsystemsthat form part of the wind power plant. The work of verifying that thewind power plantobserves limit values for high-frequency voltages must bebased on a high-frequency emission model composed by theplant owner'sdata,the electricity supply undertaking'sdata for thepublic electricity supplynetwork, and a model for wind turbine generator systemsand thepowerstructurein thepoint of connectionfor the frequency range up to 9 kHz.

4.2 Rapid voltage changes

4.2.1 Data basis

Theplant ownermust use the voltage change factor kU,i(k), which is specifiedby the type test, see IEC 61400-21, for each wind turbine generator system Iduring switching. The type test specifies kU,i(k) for the short-circuit angle k=30, 50, 70 and 85 degrees for switching. The type test also specifies thelocation of the metering point.

4.2.2 Limit values

The switching of a wind turbine generator systemin the wind power plantmustnot give rise to rapid voltage changes d(%) exceeding the limit valuesindicated in Table 3.

Voltage level (AC) d(%)Un35 kV 4%

Un> 35 kV 3%

Table 3 Limit values for rapid voltage changes d(%)

Excepted are rare voltage changes such as voltage drops as a result of theenergising of thepower infrastructurewith connected step-up transformers.

4.2.3 Verification

The voltage change factor kUis determined for thepublic electricity supplynetworkin thepoint of connection for all types of wind turbine generator

systemsand for all types of switching's through simple interpolation betweenthe values for k, as specified in the type approval. Therefore kU,i(k) is


26/74

Electricity quality


determined as the largest voltage change factor for the various types ofswitching's for of each wind turbine generator system i.

The voltage change di(%) is then determined for each wind turbine generatorsystem:

( )k

in

kiuiS

Skd

,,%100(%) =

d(%) is then determined as the highest value of di(%). Finally, it is verified thatthe calculated voltage change d(%) is below the limit values specified in Table3.

4.3 Flicker

4.3.1 Data basis

Flicker emission must be documented for continuous operation as well as forswitching.

Flicker coefficient data cf,i(k,va,i), which is specified in the type test, are usedfor continuous operation. The type certification test results for the flickercoefficient cf,i(k) at network impedance phase angle k= 30, 50, 70 and 85degrees and at annual average wind speedva= 6,0 m/s; 7,5 m/s; 8,5 m/s and

10,0 m/s average wind speeds. The annual average wind speed vafor the windpower plant is used for the calculation.

The flicker step factor kf,i(k), as specified in the type certification test, is usedfor calculating the flicker step factor from switching's. The type certification testresults for the voltage change factor kU,i(k) at network impedance phase anglek= 30; 50; 70 and 85 degrees at the point of connection In addition, themaximum number of switching's within a 10-minute period N10m,i(short-termflicker) and a 120-minute period N120m,i(long-term flicker) is used.

4.3.2 Limit values

In addition to complying with the requirements for rapid voltage changes, thewind power plant'sflicker contribution must comply with the followingrequirements in thepoint of connection. The flicker requirements are collectiverequirements that apply to all wind power plants with the samepoint of

common coupling. Collective requirements for thepoint of common coupling arechecked by the electricity supply undertaking.

4.3.2.1 Wind power plants with a power output range of 11 kW to 1.5 MWIf the connected rated poweris lower than 0.4% of Sk, the wind power plantcan be connected without any further examinations. Otherwise, the limit valuesin Table 4for emissions from the individual wind power plantapply.

Voltage level (AC) Pst Plt

Un1 kV 0.35 0.25

Un> 1 kV 0.30 0.20

Table 4 Limit values for short-term flicker (Pst) and long-term flicker (Plt)


27/74

Electricity quality


4.3.2.2 Wind power plants with a power output greater than 1.5 MWThe maximum flicker contribution Pltand Pstfrom wind power plantsconnectedat the same voltage level and to the same substation must not exceed the limitvalues in Table 5.

Voltage level (AC) Pst Plt

Un35 kV - 0.50

35 kV < Un100 kV - 0.35

Un> 100 kV 0.30 0.20

Table 5 Limit values for short-term flicker (Pst) and long-term flicker (Plt)

4.3.3 Verification

It must be verified that flicker emission from continuous operation of the windpower plantand from switching's is lower than the limit value for thepoint ofconnection.

4.3.3.1 Continuous operationThe flicker coefficient must be determined for thepublic electricity supplynetworkin thepoint of connectionand the wind power plantconcerned throughsimple interpolation between the network impedance phase angle kand annual

average wind speedvavalues, which are specified in the type certification test

specification.

Flicker emission for each individual wind turbine generator system iis calculatedas:

( )k

iniaii

SSv ,,kst, ,cP =

The emission from the entire wind power plantis then calculated as:

( )2 2st,ltst PPP ==i

i

It must be checked that the calculated values are below the limit values.

4.3.3.2 SwitchingThe flicker step factor is determined for switching's in thepublic electricitysupply networkat thepoint of connectionthrough simple interpolation betweenthe network impedance phase angle kvalues, which are specified in the typeapproval. Then kU,i(k) is determined as the largest flicker step factor forswitching's.

The flicker emission is then determined for each of the wind turbine generatorsystems ithat form part of the wind power plantby using the flicker step factorkf(k):


28/74

Electricity quality


( )

( )k

inkifiilt

k

in

kifiist

S

SkNP

S

SkNP

,,31,0 min,120,

,,

31,0min,10,

8

18

=

=

The emission from the wind power plantis then calculated as:

( )

( )3 3lt,lt

33

st,st

PP

PP

=

=

i

i

i

i

It must be checked that the calculated values are below the limit values.

4.4 Harmonics

4.4.1 Data basis

The type certification tests specifies measured mean values from the 2nd to the50th harmonic for 11 levels of generated power from 0% to 100% of the rated

powerPn,i. The measured mean values are stated as a percentage of the ratedcurrent.

4.4.2 Limit values

The wind power plantis not allowed to emit harmonics exceeding the limit

values specified in this chapter.

In addition to limit values for individual harmonics, limit values for TotalHarmonic Distortion (THD) and Partially Weighted Harmonic Distortion (PWHD)are used. For current harmonic IhTHDIand PWHDIare defined as:

=

=

=40

2

2h

h

hI ITHD and =

=

=40

14

2h

h

hI IhPWHD

Similar equations apply to THDUand PWHDUof voltage harmonic Uh.

4.4.2.1 Wind power plants with a power output range of 11 kW to 25 kWThe limit values for harmonic current emissions for different orders hcan beseen fromTable 6.

Odd-order harmonics h

(no multiple of 3)

Even-order harmonics h

(no multiple of 3)Voltage level

(AC)5 7 11 13 17h49 2 4 8h50

Un1 kV 4.8 3.3 1.3 0.9 - - - -

Un> 1 kV 4.0 4.0 2.0 2.0 2400

h*) 0.8 0.2 0.1

*) Not lower than 0.1%, however.Table 6 Limit values for harmonic current Ih/In(%)


29/74

Electricity quality


The limit values for total harmonic current distortion can be seen in Table 7.

Voltage level(AC)

THDI PWHDI

Un1 kV 6.0 10.5

Un> 1 kV - -

Table 7 Limit values for total harmonic current distortion (%)

4.4.2.2 Wind power plants with a power output range of 25 kW to 1.5 MWThe limit values for harmonic current emissions for different orders hcan beseen inTable 8.

Odd-order harmonics h

(no multiple of 3)

Even-order harmonics h

(no multiple of 3)Voltage level

(AC)5 7 11 13 17h49 2 4 8h50

Un1 kV 3.6 2.5 1.0 0.7 - - - -

Un> 1 kV 4.0 4.0 2.0 2.0 2400

h* 0.8 0.2 0.1

*) Not lower than 0.1%, however.Table 8 Limit values for harmonic currents Ih/In(%)

The limit values for total harmonic current distortion can be seen inTable 9.

Voltage level

(AC)THDI PWHDI

Un1 kV 4.5 7.9Un> 1 kV - -

Table 9 Limit values for total harmonic current distortion (%)

4.4.2.3 Wind power plants with a power output greater than 1.5 MWThe electricity supply undertakingdetermines emission limits for harmonicvoltage in thepoint of connection. The emission limits aim to ensure that theelectricity supply undertaking's design limits for the individual harmonicvoltages and THDUare not exceeded in thepoint of connection.

An example of design limits for harmonic voltage from IEC TR 61000-3-6 is

shown below. Table 10shows limits for odd-order harmonics, Table 11thelimits for even-order harmonics and Table 12the total harmonic voltagedistortion.

Odd-order harmonics h (no multiple of 3)Voltage level

(AC) 5 7 11 13 17h49 3 9 15 21h45

Un35 kV 5.0 4.0 3.0 2.5 2017

91 ,h

, *) 4.0 1.2 0.3 0.2

Un> 35 kV 2.0 2.0 1.5 1.5h

,17

21 *) 2.0 1.0 0.3 0.2

*) Not lower than 0.1%, however.Table 10 Limit values for harmonic voltage Uh/Un(%) for odd-order harmonics

h.


30/74

Electricity quality


Even-order harmonics hVoltage level(AC) 2 4 6 8 10h50

Un35 kV 1.8 1.0 0.5 0.5 220

10

25,0 ,h +

Un> 35 kV 1.4 0.8 0.4 0.4 16,010

19,0 +h

Table 11 Limit values for harmonic voltage Uh/Un(%) for even-order

harmonics h.

Voltage level(AC)

THDU

Un35 kV 6.5

Un> 35 kV 3.0

Table 12 Limit values for total harmonic voltage distortion THDU(% of Un) foreven-order harmonics h.

The emission limits for the wind power plantwill typically be lower than thedesign limits as the electricity supply undertakingmust take emissions fromother plants in thepublic electricity supply network into account.

Emission limits for wind power plantsthat are electrically connected withoutinterfering consumption can be modified to values higher than the standarddesign limits.

4.4.3 Verification

4.4.3.1 Wind power plants with a power output range of 11 kW to 1.5 MWIt must be verified that the limit values are observed at all levels of generatedpower. Therefore the value from the level of generated power at which theindividual harmonic current is the greatest is used to verify observance of thelimit values for individual harmonic currents h.

Similarly, values from the level of generated power that collectively yields thehighest THD and PWHD values, respectively, are used to verify observance ofthe THD and PWHD limit values.

As regards wind power plantsconsisting of several wind turbine generatorsystems,contributions from the individual wind turbine generator systemsmustbe added up in accordance with the general summation law in IEC 61000-3-6and IEC 61400-21:

=i

ihh II ,


31/74

Electricity quality


Values for the exponent alpha are shown in Table 13.

Harmonic order (alpha)

h< 5 1

5 h10 1.4

h> 10 2

Table 13 Values for exponent

4.4.3.2 Wind power plants with a power output greater than 1.5 MWThe high-frequency emission model for thepublic electricity supply networkisused to verify limit values for harmonic voltage in thepoint of connection. Inputto this emission model can either be the measured and aggregated values forharmonic current emissions in accordance with the above, or values provided bya validated emission model.

4.5 Interharmonics

4.5.1 Data basis

The type test specifies measured mean values for interharmonics from 75 Hz to1975 Hz for 11 levels of generated power from 0% to 100% of the rated powerPn,i. The measured mean values are stated as a percentage of the rated power.

4.5.2 Limit values

The wind power plantis not allowed to emit interharmonics exceeding the limitvalues specified in this chapter.

4.5.2.1 Wind power plants with a power output range of 11 kW to 25 kWThe limit values for the emission of interharmonic currents can be seen inTable14.

Frequency (Hz)Voltage level

(AC) 75 Hz 125 Hz >175 Hz

Un1kV 0.53 0.80f

100*)

Un> 1kV 0.44 0.66

f

83*)

*) Not lower than 0.1%, however.Table 14 Limit values for interharmonic current emissions


32/74

Electricity quality


4.5.2.2 Wind power plants with a power output range of 25 kW to 1.5 MWThe limit values for the emission of interharmonic currents can be seen inTable15.

Frequency (Hz)Voltage level

(AC) 75 Hz 125 Hz >175 Hz

Un1kV 0.40 0.60f

75*)

Un> 1kV 0.44 0.66f

83*)

*) Not lower than 0.1%, however.

Table 15 Limit values for interharmonic current emissions

4.5.2.3 Wind power plants with a power output greater than 1.5 MWThe electricity supply undertakingdetermines emission limits for interharmonicvoltages from the wind power plantin thepoint of connection. The emissionlimits aim to ensure that the electricity supply undertaking's design limits forthe individual interharmonic voltages are not exceeded in thepoint ofconnection.

Standard design limits for interharmonic voltages are shown inTable 16.

Frequency (Hz) Maximum interharmonic voltage (%)

f < 100 Hz 0.2%

100 Hz < f < 2.000 Hz 0.5%

Table 16 Standard design limits for interharmonic voltages

The emission limits for the wind power plantwill typically be lower than thedesign limits as the electricity supply undertakingmust take account ofemissions from other plants in thepublic electricity supply network.

Emission limits for wind power plantselectrically connected without interferingconsumption can be modified to values higher than the standard design limits.

4.5.3 Verification

4.5.3.1 Wind power plants with a power output range of 11 kW to 1.5 MWIt must be verified that the wind power plantcomplies with the limit values forinterharmonic current emissions in the same way as it does where harmoniccurrent emissions are concerned. The exponent =2 must be used, however.

4.5.3.2 Wind power plants with a power output greater than 1.5 MWIt must be verified that the wind power plantcomplies with the limit values forinterharmonic voltage emissions in the same way as it does where harmoniccurrents are concerned. The exponent can be seen inTable 13.


33/74


4.6 Disturbances greater than 2 kHz

4.6.1 Data basis

The type test specifies measured mean values for frequency components of thecurrent in groups of 200 Hz width from 2.1 kHz to 8.9 kHz for 11 levels ofgenerated power from 0% to 100% of the rated powerPn,i. The measured meanvalues are stated as a percentage of the rated current.

4.6.2 Limit values

4.6.2.1 Wind power plants with a power output range of 11 kW to 1.5 MWThe emission of currents with frequencies higher than 2 kHz must not exceed0.2% of the rated currentin any of the frequency groups measured.

4.6.2.2 Wind power plants with a power output greater than 1.5 MWThe electricity supply undertakingdetermines emission limits for voltages from

the wind power plantin thepoint of connection. The emission limits aim toensure that the electricity supply undertaking's design limits for the individualfrequency groups are not exceeded in thepoint of connection.

1% is used as a design limit for each frequency group.

4.6.3 Verification

It must be verified that the wind power plantcomplies with the limit values forthe emission of frequencies higher than 2 kHz in the same way as it does whereinterharmonic emissions are concerned.


34/74

Control and monitoring


5. Control and monitoring

5.1 General requirements

All control functions mentioned in the following chapters refer to thepoint ofconnection. It must be possible to activate/deactivate all the control functionsand set them using external signals, as described in chapter 7and theassociated Appendix 4. The current settings must be agreed with theelectricity supply undertakingbefore the wind power plantcan be connected tothepublic electricity supply network.

The signs used in all figures follow the generator convention. The requiredactive (MW) and reactive (Mvar) power will be reduced on a pro-rata basis inrelation to the number of wind turbine generator systems in operation in thewind power plant.

After a wind power planthas been disconnected due to a fault in thepublicelectricity supply network, the wind power plantmust at the earliest beautomatically connected three minutes after the voltage and the frequency haveonce again come to lie within the limits stated in chapter 3.1and chapter 3.2.A wind power plantwhich has been disconnected by an external signal prior to afault occurring in thepublic electricity supply networkmust not be connecteduntil the external signal has been eliminated, and the voltage and the frequencyhave once again come to lie within the limits stated in chapter 3.1andchapter 3.2.

Wind power plantswith an output greater than 1.5 MW must be equipped with

the control functions specified inTable 17. The purpose of the various controlfunctions is to ensure overall control and monitoring of the wind power plant'sgeneration. The various control functions can be implemented in the individualwind turbine generator systemor be gathered in a wind power plant controller,provided there is only one communication interface, as illustrated onFigure 7.

Figure 7 Drawing of a wind power plant controller


35/74



All setpoint changes must be registered together with an identification of theoperator.

All setpoint changes or orders for production changes must refer to UTC and betime stamped with accuracy and a precision of maximum 10 ms. TheUTCcorrection is +1 hour for winter time and +2 hours for summer time.

5.2 Active power control functions

A wind power plantmust be equipped with active power control functionscapable of controlling the active power supplied by a wind power plantin the

point of connectionusing orders containing setpoints and gradients.

The current parameter settings for active power control functions aredetermined by the electricity supply undertaking in collaboration with thetransmission system operator before commissioning.

In addition to the general requirements in chapter 5.1, the active powercontrol functions must comply with the requirements outlined in the followingchapters.

5.2.1 Frequency control

The control requirement as indicated in Figure 8must be implemented notlater than 18 months after the commencement date of this technical regulation.

In case of frequency deviations in thepublic electricity supply network, the windpower plantmust be able to provide frequency controlin order to stabilise thegrid frequency (50.00 Hz). The metering accuracy for the grid frequency mustbe 10 mHz or better.

It must be possible to set the frequency control function for all frequency pointsshown in Figure 8and Figure 9.It must be possible to set the frequencies fmin,fmax, as well as f1to f7to any value in the range of 50.00 Hz 3.00 Hz with anaccuracy of 10 mHz.

The purpose of frequency points f1to f4is to form a dead band and a controlband for primary control. The purpose of frequency points f5to f7is to supplycritical power/frequency control. The drooprequired to perform control betweenthe various frequency points is shown in Figure 8, Figure 9and the signal list

in Appendix 4. In this context, droopis the change in active power (p.u.)caused by a change in frequency (p.u.).

If the active power for the wind power plant is regulated downward below Pmin,the shutting-down of individual wind turbine generator systems is allowed.

In case of grid frequencies above f5upward regulation cannot be commenceduntil the grid frequency is lower than f7.

PDeltais the setpoint to which the available active power has been reduced inorder to provide frequency stabilisation (upward regulation) in the case offalling grid frequency. Two different PDeltavalues with the same droop (droops 1,

2, 3 and 4) are shown in Figure 8and Figure 9.


36/74



The purpose of the frequency control function is to reduce active power if gridfrequencies exceed f3, as shown in Figure 8and Figure 9.

Figure 8 Frequency control for wind power plants with a power output higher than

25 MW, as shown in connection with a minor downward regulation PDelta

50.0049.0048.0047.00 51.00 52.00

Active power

Pavailable

Frequency

[Hz]

0

f2

Deadband

PDelta

f1 f3

Pminf7

fmin

fmax

Droop 2

Droop 1

Droop 3

f4 Figure 9 Frequency control for wind power plants with a power output higher than

25 MW, as shown in connection with a major downward regulation PDelta

It must be possible to activate the frequency control function in the intervalfrom fminto fmax.

If the frequency controlsetpoint is to be changed, such change must becommenced within two seconds and completed not later than 10 seconds afterreceipt of an order to change the setpoint. The accuracy of the control


37/74



performed and of the setpoint must not deviate by more than 2% of thesetpoint value or by 0.5% of the rated power,depending on which yields thehighest tolerance.

5.2.2 Constraint functions

A wind power plantmust be equipped with constraint functions, iesupplementary active power control functions. The constraint functions are usedto avoid imbalances in or overloading of thepublic electricity supply networkinconnection with the reconfiguration of thepublic electricity supply networkinfault situations or the like.

The required constraint functions are described below.

5.2.2.1 Absolute production constraintAn absolute production constraintis used to constrain the active power from a

wind power plantto a predefined power limit in thepoint of connection. Anabsolute production constraintis typically used to protect thepublic electricitysupply networkagainst overloading.

If the frequency control setpoint for the absolute production constraint is to bechanged, such change must be commenced within two seconds and completednot later than 30 seconds after receipt of an order to change the setpoint. Theaccuracy of the control performed and of the setpoint must not deviate by morethan 2% of the setpoint value or by 0.5% of the rated power,depending onwhich yields the highest tolerance.

5.2.2.2 Delta production constraint (spinning reserve)A delta production constraintis used to constrain the active power from a wind

power plantto a required constant value in proportion to the possible activepower. A delta production constraintis typically used to establish a controlreserve for control purposes in connection with frequency control.

If the setpoint for a delta production constraint is to be changed, such changemust be commenced within two seconds and completed not later than 30seconds after receipt of an order to change the setpoint. The accuracy of thecontrol performed and of the setpoint must not deviate by more than 2% ofthe setpoint value or by 0.5% of the rated power,depending on which yieldsthe highest tolerance.

5.2.2.3 Power gradient constraintApower gradient constraint is used to limit the maximum speed by which thereactive power can be changed in the event of changes in wind speed or thesetpoints for a wind power plant.Apower gradient constraintis typically usedfor reasons of system operation to prevent changes in active power fromimpacting the stability of thepublic electricity supply network.

If a setpoint for thepower gradient constraint is to be changed, such changemust be commenced within two seconds and completed not later than 30seconds after receipt of an order to change the setpoint. The accuracy of the

control performed and of the setpoint must not deviate by more than 2% of


38/74



the setpoint value or by 0.5% of the rated power,depending on which yieldsthe highest tolerance.

In, the active power constraint functions are illustrated on Figure 10.

Possible active power

Activation of delta

production constraint

Time

Active power

Spinning

reserve

Activation of delta and

deactivation

gradient production constraint

Deactivation of absolutproduction constraint

Activation of gradientproduction constraint

Activation of active power

production constraint

Figure 10 Drawing of active power constraint functions

5.3 Reactive power and voltage control functionsA wind power plant must be equipped with reactive power control functionscapable of controlling the reactive power supplied by a wind power plant in the

point of connectionas well as a voltage control function capable of controllingthe voltage in thepoint of connection via orders using setpoints and gradients.

The reactive power and voltage control functions are mutually exclusive, whichmeans that only one of the three functions can be activated at a time.

The current parameter settings for reactive power control and voltage functionsmust be determined before commissioning by the electricity supply undertakingin collaboration with the transmission system operator.

In addition to complying with the general requirements in chapter 5.1, thereactive power and voltage control functions must comply with therequirements laid down in the following chapters.


39/74



5.3.1 Q control

Q control is a control function controlling the reactive power independently ofthe active power in thepoint of connection. This control function is illustrated

on Figure 11as a vertical line.

If the Q control setpoint is to be changed, such change must be commencedwithin two seconds and completed not later than 30 seconds after receipt of anorder to change the setpoint. The accuracy of the control performed and of thesetpoint must not deviate by more than 2% of the setpoint value or by 0.5%of the rated power,depending on which yields the highest tolerance.

The wind power plantmust be able to receive a Q setpoint with an accuracy of1 kvar.

5.3.2

Power factor controlPower factor control is a control function controlling the reactive powerproportionally to the active power in thepoint of connection, which is illustratedon Figure 11by a line with a constant gradient. The gradient of the line isknown as the power factor.

The wind power plantmust be able to receive a power factor setpoint with anaccuracy of 0.001 kvar.

Figure 11 Reactive power control functions for a wind power plant

If the power factor setpoint is to be changed, such change must be commencedwithin two seconds and completed not later than 30 seconds after receipt of anorder to change the setpoint. The accuracy of the control performed and of thesetpoint must not deviate by more than 2% of the setpoint value or by 0.5%of the rated power,depending on which yields the highest tolerance.


40/74


41/74



5.4 System protection

A wind power plant must be equipped with system protection, which is a controlfunction capable of automatically downward regulating the active power from awind power plantto one or several predefined setpoints. The setpoints aredetermined by the electricity supply undertaking upon commissioning.

It must be possible to set up at least five different setpoints for the wind powerplant.

If the system protection setpoint is to be changed, such change must becommenced within one second and completed not later than 10 seconds afterreceipt of an order to change the setpoint. The accuracy of the controlperformed and of the setpoint must not deviate by more than 2% of thesetpoint value or by 0.5% of the rated power,depending on which yields thehighest tolerance.

5.5 Order of priority for control functions

The individual control functions of a wind power plantmust be ranked in orderof priority vis--vis each other. A priority 1 control function takes precedenceover a priority 2 control function etc. The order of priority recommended is asfollows:

1. System protection2. Frequency control3. Constraint functions

It must be possible to arrange control functions in order of priority by means of

orders.

5.6 Overview of control functions for wind power stations

Wind power plantswith a power output greater than 1.5 MW must be equippedwith the control functions specified in Table 17. The table shows the minimumrequirements divided on the basis of the total rated power in thepoint ofconnection.

The specifications and regulation functions specified must comply with theinternational standard IEC 61400-25-2 [ref. 17].

Control function 1.5 MW < P < 25 MW P > 25 MW

Frequency control (5.2.1) * - X

Absolute production constraint (5.2.2.1) X X

Delta production constraint (5.2.2.2) - X

Power gradient constraint (5.2.2.3) X X

System protection (5.4) X X

Q control (5.3.1) X X

Power factor control (5.3.2) X X

Voltage control (5.3.3) * - X

Table 17 Control functions for a wind power plant


42/74



*) A wind power plant must not perform frequency control or voltage controlwithout having entered into a specific agreement to this effect with theelectricity supply undertaking.

5.7 Active power control requirements


In addition to complying with the general requirements in chapter 5.1and therequirements for normal production in chapter 3.2, the wind power plant mustbe prepared for receiving an external stop signal. The external signal isexpected to be a pulse signal.

The requirement is regarded as having been complied with if the normal stopcircuit can be controlled by the external stop signal via a terminal strip.


In addition to complying with the general requirements in chapter 5.1, and therequirements for normal production in chapter 3.2, the wind power plantmustbe prepared for receiving an external start signal (released) and an externalstop signal.

The signals must be accessible via a terminal strip or commands in accordancewith the specifications in chapter 7.

5.7.3 Wind power plants with a power output range of 1.5 MW to 25 MW

The requirement for automatic downward control in case of strong winds mustbe implemented not later than 18 months after the commencement date of thistechnical regulation.

In addition to complying with the general requirements in chapter 5.1and therequirements for normal production in chapter 3.2, the wind power plant mustbe equipped with the control functions specified in Table 17.

Awind power plantmust be prepared for receiving an external start signal(released) and an external stop signal. The signals must be accessible viacommands in accordance with the specifications in chapter 7.

It must be possible to continuously downward regulate the active powersupplied by the wind power plantto an arbitrary value in the interval from100% to at least 40% of the rated power. When downward regulation isperformed, the shutting-down of individual wind turbine generator systemsisallowed so that the load characteristic is followed as well as possible.

The wind power plantmust stay connected to thepublic electricity supplynetworkat average wind speeds below a predefined cut-out wind speed. Thecut-out wind speedmust as a minimum be 25 m/s, based on the wind speedmeasured as an average value over a 10-minute period. To prevent instabilityin thepublic electricity supply network the wind power plant must be equippedwith an automatic downward regulation function making it possible to avoid atemporary interruption of the active power production at wind speeds close tothe cut-out wind speed.


43/74



Downward regulation can be performed as continuous or discrete regulation.Discrete regulation must have a step size of maximum 25% of the rated powerwithin the hatched area shown in Figure 13. When downward regulation isbeing performed, the shutting-down of individual wind turbine generatorsystemsis allowed. The downward regulation band must be agreed with theelectricity supply undertakingupon commissioning of the wind power plant.

Figure 13 Downward regulation of active power at high wind speeds

5.7.4 Wind power plants with a power output greater than 25 MW

In addition to complying with the requirements in chapter 5.7.3the windpower plantmust be able to continuously regulate the active power to anarbitrary value in the interval from 100% to as least 20% of the rated power.

5.8 Calculation of non-supplied active power

As regards wind power plantssubject to legislation relating to compensation inthe event of downward regulation being ordered as described in the regulation'Compensation for offshore wind farms ordered to perform downward

regulation'[Ref. 27], the wind turbine generator system operatormust providethe required signals, as specified in Appendix 4.

5.9 Reactive power control requirements


In addition to complying with the general requirements in chapter 5.1, and therequirements for normal production stated in chapter 3.2, the wind power

plant must comply with a power factor interval of 0.95 < PF < 1.0 if productionconstitutes more than 20% of the rated power.


In addition to complying with the general requirements in chapter 5.1 and the

requirements for normal production in chapter 3.2, the wind power plant'soperating point must always be within the hatched area shown in Figure 14.


44/74


45/74



+

Figure 15 Reactive power requirements for wind power plants with a power

output range of 1.5 MW to 25 MW

Wind turbine types already type-approved must be able to control reactivepower in accordance with the current type approval or the wind turbinemanufacturer's technical specifications applying at the time of commencementof this technical regulation.

5.9.4 Wind power plants with a power output greater than 25 MW

In addition to complying with the general requirements in chapter 5.1and therequirements for normal production in chapter 3.2, the wind power plant mustbe equipped with the control functions specified in Table 17.

The wind power plant must be designed in such a way that the operating pointcan lie anywhere within the hatched area in Figure 16 and Figure 17.

Control form and settings must be agreed with the electricity supplyundertaking.

Theplant owneris responsible for carrying out compensation in situations when

the wind power plantis disconnected or is not producing active power (reactivepower from thepower infrastructure). Following agreement with the electricitysupply undertaking, compensation can be carried out outside of the wind power

plant.


46/74



0.00- 0.228- 0.330- 0.410 0.228 0.330 0.410

P / Pn

1.0

0.8

0.6

0.4

0.2

Q/Pmax

+

0.0

- 0.480

1.0000.9750.9500.925 0.975 0.950 0.9250.900 Cos

InductivE

Q-import

Capacitive

Q-export

Figure 16 Reactive power requirements for wind power plants with a power

output greater than 25 MW

0.00- 0.228- 0.330- 0.410 0.228 0.330 0.410

U

Q/Pmax

+

1.0000.9750.9500.925 0.975 0.950 0.925 Cos

Nominal voltages see table 1

U +10%

U

U -10%

Umin

Umax

U +5%

U -5%

U +6%

Figure 17 Requirements for voltage control range for wind power plants with

a power output greater than 25 MW

Wind turbine types already type-approved must be able to control reactivepower in accordance with the current type approval or the wind turbinemanufacturer's technical specifications applying at the time of commencementof this technical regulation.


47/74

Protection


6. Protection

6.1 General

Protection functions must be available to protect the wind power plantand toensure a stablepublic electricity supply network.

Theplant owneris responsible for ensuring that a wind power plantisdimensioned and equipped with the necessary protection functions so that thewind power plant:

- is protected against damage due to faults and incidents in thepublicelectricity supply network, eg symmetrical and asymmetrical short circuits,recurring voltages when faults and incidents are disconnected, increasedvoltage on fault-free phases in the event of asymmetrical short circuits,phase failures, etc.

- is protected against damage due to out-of-phase reclosing- protects thepublic electricity supply networkto the widest possible extentagainst unwanted impacts from the wind power plant

- is protected against disconnection in non-critical situations for the windpower plant.

The electricity supply undertakingor the transmission system operatorisentitled to demand that the set values for protection functions be changedfollowing commissioning if it is deemed to be of importance to the operation ofthepublic electricity supply network. However, such change must not result inthe wind power plantbeing exposed to impacts from thepublic electricitysupply networklying outside of the design requirements specified in chapter 3.

The electricity supply undertakingmust state the highest and lowest short-circuit current that can be expected in thepoint of connectionas well as anyother information about thepublic electricity supply networkas may benecessary to define the wind power plant's protection functions.

6.2 Requirements for grid protection in the point of connection

The wind power plant'sprotection functions and associated settings must be asspecified in the following subsections. Settings deviating from the requirementscan only be used if authorised by the electricity supply undertaking.

All settings are stated as RMS values. The wind power plantmust bedisconnected or stopped if a measuring signal deviates more from its nominalvalue than the setting.

The function time stated is the measuring time in which the trip condition mustconstantly be complied with in order for the protection function to issue a tripsignal. It is not a question of the trip signal being subjected to a simple timelag.

The use of v

55986-10_v1_grid code 3 2 5_v 4 1-30 september 2010

Documents