EN 61400-21:2008

SLOVENSKI STANDARD
01-januar-2009
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Wind turbines -- Part 21: Measurement and assessment of power quality characteristics
of grid connected wind turbines
Windenergieanlagen --Teil 21: Messung und Bewertung der Netzverträglichkeit von
netzgekoppelten Windenergieanlagen
Eoliennes -- Partie 21: Mesure et évaluation des caractéristiques de qualité de puissance
des éoliennes connectées au réseau
Ta slovenski standard je istoveten z: EN 61400-21:2008
ICS:
27.180 Sistemi turbin na veter in Wind turbine systems and
drugi alternativni viri energije other alternative sources of
energy
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61400-21
NORME EUROPÉENNE
November 2008
EUROPÄISCHE NORM
ICS 27.180 Supersedes EN 61400-21:2002

English version
Wind turbines -
Part 21: Measurement and assessment
of power quality characteristics of grid connected wind turbines
(IEC 61400-21:2008)
Eoliennes -  Windenergieanlagen -
Partie 21: Mesurage et évaluation Teil 21: Messung und Bewertung
des caractéristiques de qualité der Netzverträglichkeit
de puissance des éoliennes von netzgekoppelten
connectées au réseau Windenergieanlagen
(CEI 61400-21:2008) (IEC 61400-21:2008)

This European Standard was approved by CENELEC on 2008-10-01. CENELEC members are bound to comply
with 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 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 official 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, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für 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 members.
Ref. No. EN 61400-21:2008 E
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 by CENELEC as
EN 61400-21 on 2008-10-01.
This European Standard supersedes EN 61400-21:2002.
– interharmonics and current distortions (< 9 kHz),
– response to voltage dips,
– active power ramp rate limitation and set-point control,
– reactive power capabilities and set-point control,
– grid protection and reconnection time after grid faults.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61400-21:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 61000-3-3 NOTE  Harmonized as EN 61000-3-3:2008 (not modified).
IEC 61000-4-30 NOTE  Harmonized as EN 61000-4-30:2003 (not modified).
IEC 61400-1 NOTE  Harmonized as EN 61400-1:2005 (not modified).
__________
– 3 – EN 61400-21:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable 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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

1) 2)
IEC 60044-1 - Instrument transformers - EN 60044-1 1999
(mod) Part 1: Current transformers

1) 2)
IEC 60044-2 - Instrument transformers - EN 60044-2 1999
(mod) Part 2: Inductive voltage transformers

1)
IEC 60050-161 - International Electrotechnical Vocabulary - -
(IEV) -
Chapter 161: Electromagnetic compatibility

1)
IEC 60050-415 - International Electrotechnical Vocabulary - -
(IEV) -
Part 415: Wind turbine generator systems

IEC 61000-4-7 2002 Electromagnetic compatibility (EMC) - EN 61000-4-7 2002
Part 4-7: Testing and measurement
techniques - General guide on harmonics and
interharmonics measurements and
instrumentation, for power supply systems
and equipment connected thereto

1) 2)
IEC 61000-4-15 - Electromagnetic compatibility (EMC) - EN 61000-4-15 1998
Part 4-15: Testing and measurement
techniques - Flickermeter - Functional and
design specifications
1) 2)
IEC 61400-12-1 - Wind turbines - EN 61400-12-1 2006
Part 12-1: Power performance measurements
of electricity producing wind turbines

IEC 61800-3 2004 Adjustable speed electrical power drive EN 61800-3 2004
systems -
Part 3: EMC requirements and specific test
methods
1) 2)
IEC 62008 - Performance characteristics and calibration EN 62008 2005
methods for digital data acquisition systems
and relevant software
1)
Undated reference.
2)
Valid edition at date of issue.

IEC 61400-21
Edition 2.0 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Wind turbines –
Part 21: Measurement and assessment of power quality characteristics of grid
connected wind turbines
Eoliennes –
Partie 21: Mesurage et évaluation des caractéristiques de qualité de puissance
des éoliennes connectées au réseau

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XA
CODE PRIX
ICS 27.180 ISBN 2-8318-9938-9
– 2 – 61400-21 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms and definitions .8
4 Symbols and units .11
5 Abbreviations .13
6 Wind turbine power quality characteristic parameters .14
6.1 General .14
6.2 Wind turbine specification .14
6.3 Voltage fluctuations.14
6.3.1 General .14
6.3.2 Continuous operation .14
6.3.3 Switching operations .15
6.4 Current harmonics, interharmonics and higher frequency components .15
6.5 Response to voltage drops .16
6.6 Active power .16
6.6.1 Maximum measured power .16
6.6.2 Ramp rate limitation .16
6.6.3 Set-point control .17
6.7 Reactive power .17
6.7.1 Reactive power capability .17
6.7.2 Set-point control .17
6.8 Grid protection .18
6.9 Reconnection time.18
7 Test procedures .18
7.1 General .18
7.1.1 Test validity.19
7.1.2 Test conditions .19
7.1.3 Test equipment.20
7.2 Wind turbine specification .21
7.3 Voltage fluctuations.21
7.3.1 General .21
7.3.2 Fictitious grid.21
7.3.3 Continuous operation .23
7.3.4 Switching operations .26
7.4 Current harmonics, interharmonics and higher frequency components .27
7.5 Response to temporary voltage drop .28
7.6 Active power .30
7.6.1 Maximum measured power .30
7.6.2 Ramp rate limitation .31
7.6.3 Set point control .31
7.7 Reactive power .31
7.7.1 Reactive power capability .31
7.7.2 Set point control .32
7.8 Grid protection .32

61400-21 © IEC:2008 – 3 –
7.9 Reconnection time.33
8 Assessment of power quality .34
8.1 General .34
8.2 Voltage fluctuations.34
8.2.1 General .34
8.2.2 Continuous operation .35
8.2.3 Switching operations .35
8.3 Current harmonics, interharmonics and higher frequency components .36
Annex A (informative) Sample report format.38
Annex B (informative) Voltage fluctuations and flicker.48
Annex C (informative) Measurement of active power, reactive power and voltage.56
Bibliography.58

Figure 1 – Adjustment of active power set-point.17
Figure 2 – Adjustment of reactive power set-point.
...