1、Wind turbines Part 21: Measurement and assessment of power qualitycharacteristics of grid connected wind turbinesBS EN 61400-21:2008raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British StandardsNational forewordThis British Standard is the UK i
2、mplementation of EN 61400-21:2008. It isidentical to IEC 61400-21:2008. It supersedes BS EN 61400-21:2002 which iswithdrawn.The UK participation in its preparation was entrusted to Technical CommitteePEL/88, Wind turbines.A list of organizations represented on this committee can be obtained onreques
3、t to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity fromlegal obligations. BSI 200ISBN 978 0 580 56750 6ICS 27.180Amendments issued since
4、 publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 61400-21:20089This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 January 2009. EUROPEAN STANDARD EN 61400-21 NORME EUROPENNE EUROPISCHE NORM November 2008 CENELEC European Committee
5、for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC membe
6、rs. Ref. No. EN 61400-21:2008 E ICS 27.180 Supersedes EN 61400-21:2002English version Wind turbines - Part 21: Measurement and assessment of power quality characteristics of grid connected wind turbines (IEC 61400-21:2008) Eoliennes - Partie 21: Mesurage et valuation des caractristiques de qualit de
7、 puissance des oliennes connectes au rseau (CEI 61400-21:2008) Windenergieanlagen - Teil 21: Messung und Bewertung der Netzvertrglichkeit von netzgekoppelten Windenergieanlagen (IEC 61400-21:2008) This European Standard was approved by CENELEC on 2008-10-01. CENELEC members are bound to comply with
8、the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat
9、 or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the off
10、icial versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portuga
11、l, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61400-21:2008EN 61400-21:2008 2 Foreword The text of document 88/317/FDIS, future edition 2 of IEC 61400-21, prepared by IEC TC 88, Wind turbines, was submitted to the IEC-CENELEC parallel vote and was approved
12、by CENELEC as EN 61400-21 on 2008-10-01. This European Standard supersedes EN 61400-21:2002. EN 61400-21:2008 includes the following new items with respect to EN 61400-21:2002: interharmonics and current distortions ( 35 kV. 2 Normative references The following referenced documents are indispensable
13、 for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60044-1, Instrument transformers Part 1: Current transformers IEC 60044-2, Instrument transformer
14、s Part 2: Inductive voltage transformers BS EN 61400-21:2008 8 61400-21 IEC:2008 IEC 60050-161, International Electrotechnical Vocabulary Part 161: Electromagnetic compatibility IEC 60050-415, International Electrotechnical Vocabulary Part 415: Wind turbine generator systems IEC 61000-4-7:2002, Elec
15、tromagnetic compatibility (EMC) Part 4-7: Testing and measurement techniques General guide on harmonics and interharmonics measurements and instrumentation, for power supply systems and equipment connected thereto IEC 61000-4-15, Electromagnetic compatibility (EMC) Part 4: Testing and measurement te
16、chniques Section 15: Flickermeter Functional and design specifications IEC 61400-12-1, Wind turbines Part 12-1: Power performance measurements of electricity producing wind turbines IEC 61800-3:2004, Adjustable speed electrical power drive systems Part 3: EMC requirements and specific test methods I
17、EC 62008, Performance characteristics and calibration methods for digital data acquisition systems and relevant software 3 Terms and definitions For purposes of this document, the following terms and definitions apply. 3.1 continuous operation (for wind turbines) normal operation of the wind turbine
18、 excluding start-up and shutdown operations 3.2 cut-in wind speed (for wind turbines) lowest wind speed at hub height at which the wind turbine starts to produce power IEV 415-03-05 3.3 flicker coefficient for continuous operation (for wind turbines) normalized measure of the flicker emission during
19、 continuous operation of the wind turbine: ()nfick,ficst,kSSPc = where Pst,ficis the flicker emission from the wind turbine on the fictitious grid; Snis the rated apparent power of the wind turbine; Sk,ficis the short-circuit apparent power of the fictitious grid NOTE The flicker coefficient for con
20、tinuous operation is the same for a short-term (10 min) and long-term period (2 h). 3.4 flicker step factor (for wind turbines) a normalized measure of the flicker emission due to a single switching operation of the wind turbine: BS EN 61400-21:200861400-21 IEC:2008 9 31,0pficst,nfick,kf1301)( TPSSk
21、 = where Tpis the measurement period, long enough to ensure that the transient of the switching operation has abated, though limited to exclude possible power fluctuations due to turbulence; Pst,ficis the flicker emission from the wind turbine on the fictitious grid; Snis the rated apparent power of
22、 the wind turbine; Sk,ficis the short-circuit apparent power of the fictitious grid NOTE The flicker coefficient Pst,ficis here evaluated over the time period Tp. 3.5 maximum measured power (for wind turbines) power (with a specified averaging time) which is observed during continuous operation of t
23、he wind turbine 3.6 network impedance phase angle phase angle of network short-circuit impedance: )(arctankkkRX= where Xkis the network short-circuit reactance; Rkis the network short-circuit resistance 3.7 normal operation (for wind turbines) fault free operation complying with the description in t
24、he wind turbine manual 3.8 operational mode (for wind turbines) operation according to control setting, for example voltage control mode, frequency control mode, reactive power control mode, active power control mode, etc. 3.9 output power (for wind turbines) electric active power delivered by the w
25、ind turbine at its terminals IEV 415-04-02, modified 3.10 point of common coupling PCC point of a power supply network, electrically nearest to a particular load, at which other loads are, or may be, connected NOTE 1 These loads can be either devices, equipment or systems, or distinct customers inst
26、allations. NOTE 2 In some applications, the term “point of common coupling” is restricted to public networks. IEV 161-07-15, modified 3.11 power collection system (for wind turbines) electrical system that collects the power from a wind turbine and feeds it into an electrical supply network BS EN 61
27、400-21:2008 10 61400-21 IEC:2008 IEV 415-04-06, modified 3.12 rated apparent power (for wind turbines) apparent power from the wind turbine while operating at rated current and nominal voltage and frequency: nnIUS 3n= where Unis the nominal voltage; Inis the rated current 3.13 rated current (for win
28、d turbines) maximum continuous electric output current which a wind turbine is designed to achieve under normal operating conditions 3.14 rated power (for wind turbines) maximum continuous electric output power which a wind turbine is designed to achieve under normal operating conditions IEV 415-04-
29、03, modified 3.15 rated wind speed (for wind turbines) wind speed at which a wind turbines rated power is achieved IEV 415-03-04, modified 3.16 standstill (for wind turbines) condition of a wind turbine that is stopped IEV 415-01-15, modified 3.17 start-up (for wind turbines) transitional state of a
30、 wind turbine between standstill and power production 3.18 switching operation (for wind turbines) start-up or switching between generators 3.19 turbulence intensity ratio of the wind speed standard deviation to the mean wind speed, determined from the same set of measured data samples of wind speed
31、, and taken over a specified period of time IEV 415-03-25 3.20 voltage change factor (for wind turbines) a normalized measure of the voltage change due to a switching operation of the wind turbine: nfick,nminfic,maxfic,ku3)(SSUUUk = BS EN 61400-21:200861400-21 IEC:2008 11 where Ufic,minand Ufic,maxa
32、re the minimum and maximum one period RMS value of the phase-to-neutral voltage on the fictitious grid during the switching operation; Unis the nominal phase-to-phase voltage; Snis the rated apparent power of the wind turbine; Sk,ficis the short-circuit apparent power of the fictitious grid. NOTE Th
33、e voltage change factor kuis similar to kibeing the ratio between the maximum inrush current and the rated current, though kuis a function of the network impedance phase angle. The highest value of kuwill be numerically close to ki. 3.21 wind turbine WT system which converts kinetic wind energy into
34、 electric energy 3.22 wind turbine terminals point being a part of the WT and identified by the WT supplier at which the WT may be connected to the power collection system 4 Symbols and units In this part of IEC 61400, the following symbols and units are used. ndynUUmaximum permitted voltage change
35、(%)knetwork impedance phase angle ()m(t) electrical angle of the fundamental of the measured voltage () exponent associated with summation of harmonics c(k) flicker coefficient for continuous operation d relative voltage change (%) EPltilong-term flicker emission limit EPstishort-term flicker emissi
36、on limit fgnominal grid frequency (50 Hz or 60 Hz) fm,ifrequency of occurrence of flicker coefficient values within the ith wind speed bin foverover-frequency protection level funderunder-frequency protection level fy,ifrequency of occurrence of wind speeds within the ith wind speed bin h harmonic o
37、rder BS EN 61400-21:2008 12 61400-21 IEC:2008 Ih,ihth order harmonic current distortion of ith wind turbine (A) im(t) measured instantaneous current (A) Inrated current (A) kf(k) flicker step factor kiratio of maximum inrush current and rated current ku(k) voltage change factor Lficinductance of fic
38、titious grid (H) N10mmaximum number of one type of switching operations within a 10 min period N120mmaximum number of one type of switching operations within a 120 min period Nbintotal number of wind speed bins between vcut-inand 15 m/s niratio of the transformer at the ith wind turbine Nmtotal numb
39、er of measured flicker coefficient values Nm,inumber of measured flicker coefficient values within the ith wind speed bin Nm,i,c 6 m/s. BS EN 61400-21:2008 26 61400-21 IEC:2008 7.3.4 Switching operations Based on manufacturers information, the maximum number of switching operations, N10mand N120msha
40、ll be determined for each type of switching operation specified in 6.3.3. In the event that the wind turbine manufacturer cannot provide these numbers, or the manufacturer cannot provide sufficient specification of the wind turbine control system to support the provided numbers, the following shall
41、be assumed: a) Wind turbine start-up at cut-in wind speed: N10m= 10 and N120m= 120. b) Wind turbine start-up at rated wind speed or higher wind speed: N10m= 1 and N120m= 12. c) The worst case of switching between generators: N10m= 10 and N120m= 120. Measurements and subsequent simulations and calcul
42、ations shall be prepared to determine the voltage change factor ku(k), and the flicker step factor kf(k) for each type of switching operation specified in 6.3.3. This subclause gives the detailed procedure, whereas an informative outline is provided in Clause B.2. Whereas 6.3.3 a) and 6.3.3 b) each
43、specify a switching at a specific wind speed, it is the task of the assessor to identify the conditions of 6.3.3 c). This may be done by assessment of the wind turbine design, or if this does not give sufficient evidence, measurements shall be taken to identify the conditions for 6.3.3 c). See also
44、Note 1 in 6.3.3. To determine the voltage change factor ku(k), and the flicker step factor kf(k), the following measurements shall be prepared: i) The three instantaneous line currents and the three instantaneous phase-to-neutral voltages shall be measured at the wind turbine terminals. ii) The meas
45、urements shall be taken for a period, Tp, long enough to ensure that the transient of the switching operation has abated, though limited to exclude possible power fluctuations due to turbulence. iii) In order to ensure that the results of the measurements are representative of the normal average con
46、ditions, each case should be performed five times. iv) The wind speed shall be measured according to 7.1.3. The 1 min average wind speed during the switching operation shall be within a range of 2 m/s of the required wind speed. The measurements shall be taken with a measurement set-up as specified
47、in Figure 3, and by applying voltage and current transformers and an anemometer with specifications according to Table 2. The cut-off frequency of the voltage and current measurements shall be at least 1 500 Hz (see Note 1). As a guidance, for wind turbines applying soft-starters or other effective
48、limitation of the inrush currents, the current transformers should be rated two to four times the rated current. For wind turbines without any inrush current limitation, as a guidance, the current transformers should be rated 10 to 20 times the rated current of the wind turbine. The measurements sha
49、ll be treated to determine the voltage change factor and the flicker step factor. This shall be done applying the following procedure. 1) The measured time-series shall be combined to give voltage time-series of ufic(t). 2) The simulated voltage time-series of ufic(t) shall be input to the flicker algorithm in compliance with IEC 61000-4-15 to give one flicker emission value Pst,ficon the fictitious grid for each time-series of ufic(t). This will
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