EN IEC 61400-12-1:2022

SLOVENSKI STANDARD
01-december-2022
Nadomešča:
SIST EN 61400-12-1:2017
SIST EN 61400-12-1:2017/AC:2020
SIST EN 61400-12-1:2017/AC:2020
SIST EN 61400-12-1:2017/AC:2021
Sistemi za proizvodnjo energije na veter - 12-1. del: Preskušanje zmogljivosti
vetrnih turbin za proizvodnjo električne energije (IEC 61400-12-1:2022)
Wind energy generation systems - Part 12-1: Power performance measurement of
electricity producing wind turbines (IEC 61400-12-1:2022)
Windenergieanlagen - Teil 12-1: Messung des Leistungsverhaltens von
Windenergieanlagen (IEC 61400-12-1:2022)
Systèmes de génération d'énergie éolienne - Partie 12-1: Mesures de performance de
puissance des éoliennes de production d'électricité (IEC 61400-12-1:2022)
Ta slovenski standard je istoveten z: EN IEC 61400-12-1:2022
ICS:
27.180 Vetrne elektrarne Wind turbine energy systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61400-12-1

NORME EUROPÉENNE
EUROPÄISCHE NORM October 2022
ICS 27.180 Supersedes EN 61400-12-1:2017;
EN 61400-12-1:2017/AC:2019-12;
EN 61400-12-1:2017/AC:2020-04;
EN 61400-12-1:2017/AC:2021-06
English Version
Wind energy generation systems - Part 12-1: Power
performance measurements of electricity producing wind
turbines
(IEC 61400-12-1:2022)
Systèmes de génération d'énergie éolienne - Partie 12-1: Windenergieanlagen - Teil 12-1: Messung des
Mesurages de performance de puissance des éoliennes de Leistungsverhaltens von Windenergieanlagen
production d'électricité (IEC 61400-12-1:2022)
(IEC 61400-12-1:2022)
This European Standard was approved by CENELEC on 2022-10-10. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61400-12-1:2022 E

European foreword
The text of document 88/822/CDV, future edition 3 of IEC 61400-12-1, prepared by IEC/TC 88 "Wind
energy generation systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 61400-12-1:2022.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-07-10
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2025-10-10
document have to be withdrawn
This document supersedes EN 61400-12-1:2017 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61400-12-1:2022 was approved by CENELEC as a
European Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60688 - Electrical measuring transducers for EN 60688 -
converting AC and DC electrical quantities
to analogue or digital signals
IEC 61400-2 - Wind turbines - Part 2: Small wind turbines EN 61400-2 -
IEC 61400-12-2 - Wind energy generation systems - Part 12- EN IEC 61400-12-2 -
2: Power performance of electricity
producing wind turbines based on nacelle
anemometry
IEC 61400-12-3 - Wind energy generation systems - Part 12- EN IEC 61400-12-3 -
3: Power performance - Measurement
based site calibration
IEC 61400-12-5 - Wind energy generation systems - Part 12- EN IEC 61400-12-5 -
5: Power performance - Assessment of
obstacles and terrain
IEC 61400-50-1 - Wind energy generation systems - Part 50- EN IEC 61400-50-1 -
1: Wind Measurement - Application of
Meteorological Mast, Nacelle and Spinner
Mounted Instruments
IEC 61400-50-2 - Wind energy generation systems - Part 50- EN IEC 61400-50-2 -
2: Wind measurement - Application of
ground-mounted remote sensing
technology
IEC 61869-1 - Instrument transformers - Part 1: General EN 61869-1 -
requirements
IEC 61869-2 - Instrument transformers - Part 2: Additional EN 61869-2 -
requirements for current transformers
IEC 61869-3 - Instrument transformers - Part 3: Additional EN 61869-3 -
requirements for inductive voltage
transformers
Under preparation. Stage at the time of publication: FprEN IEC 61400-50-1:2022.
ISO 2533 - Standard Atmosphere - -
ISO/IEC Guide 98-3 2008 Uncertainty of measurement - Part 3: - -
Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 61400-12-1 ®
Edition 3.0 2022-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Wind energy generation systems –

Part 12-1: Power performance measurements of electricity producing wind

turbines
Systèmes de génération d'énergie éolienne –

Partie 12-1: Mesurages de performance de puissance des éoliennes de

production d'électricité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.180 ISBN 978-2-8322-5621-3

– 2 – IEC 61400-12-1:2022 © IEC 2022
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 13
4 Symbols, units and abbreviated terms . 16
5 Power performance method overview . 23
6 Preparation for performance test . 26
6.1 General . 26
6.2 Wind turbine and electrical connection . 26
6.3 Test site . 27
6.3.1 General . 27
6.3.2 Location of the wind measurement equipment . 27
6.3.3 Measurement sector . 27
6.3.4 Correction factors and uncertainty due to flow distortion originating from
topography . 28
7 Test equipment . 28
7.1 Electric power . 28
7.2 Wind speed . 29
7.2.1 General . 29
7.2.2 General requirements for meteorological mast mounted anemometers . 30
7.2.3 Top-mounted anemometers . 30
7.2.4 Side-mounted anemometers . 31
7.2.5 Remote sensing device (RSD) . 31
7.2.6 Rotor equivalent wind speed measurement . 31
7.2.7 Hub height wind speed measurement . 32
7.2.8 Wind shear measurements . 32
7.3 Wind direction . 34
7.4 Air density. 34
7.5 Rotational speed and pitch angle . 35
7.6 Blade condition . 35
7.7 Wind turbine control system . 35
7.8 Data acquisition system . 35
8 Measurement procedure . 36
8.1 General . 36
8.2 Wind turbine operation . 36
8.3 Data collection . 36
8.4 Data rejection . 36
8.5 Database . 37
9 Derived results . 37
9.1 Data normalization . 37
9.1.1 General . 37
9.1.2 Correction for meteorological mast flow distortion of side-mounted
anemometer . 38
9.1.3 Wind shear correction (when REWS measurements available) . 38
9.1.4 Wind veer correction . 41

IEC 61400-12-1:2022 © IEC 2022 – 3 –
9.1.5 Air density normalization. 41
9.1.6 Turbulence normalization . 42
9.2 Determination of the measured power curve . 42
9.3 Annual energy production (AEP) . 43
9.4 Power coefficient . 45
10 Reporting format . 45
Annex A (normative) Assessment of obstacles . 53
Annex B (normative) Assessment of terrain at the test site . 54
Annex C (normative) Site calibration procedure . 55
Annex D (normative) Evaluation of uncertainty in measurement . 56
Annex E (informative) Theoretical basis for determining the uncertainty of
measurement using the method of bins . 59
E.1 General . 59
E.2 Combining uncertainties . 60
E.2.1 General . 60
E.2.2 Expanded uncertainty . 62
E.2.3 Basis for the uncertainty assessment . 62
E.3 Category A uncertainties . 67
E.3.1 General . 67
E.3.2 Category A uncertainty in electric power . 67
E.3.3 Category A uncertainties in the site calibration . 67
E.4 Category B uncertainties: Introduction and data acquisition system . 67
E.4.1 Category B uncertainties: Introduction . 67
E.4.2 Category B uncertainties: Data acquisition system . 68
E.5 Category B uncertainties: Power output . 68
E.5.1 General . 68
E.5.2 Category B uncertainties: Power output – Current transformers . 69
E.5.3 Category B uncertainties: Power output – Voltage transformers . 69
E.5.4 Category B uncertainties: Power output – Power transducer or other
power measurement device . 70
E.5.5 Category B uncertainties: Power output – Data acquisition . 70
E.6 Category B uncertainties: Wind speed – Introduction and sensors . 71
E.6.1 Category B uncertainties: Wind speed – Introduction . 71
E.6.2 Category B uncertainties: Wind speed – Hardware . 71
E.6.3 Category B uncertainties: Wind speed – Meteorological mast mounted
sensors. 71
E.7 Category B uncertainties: Wind speed – RSD . 73
E.7.1 General . 73
E.7.2 Category B uncertainties: Wind speed – RSD – Calibration . 73
E.7.3 Category B uncertainties: Wind speed – RSD – In-situ check. 74
E.7.4 Category B uncertainties: Wind speed – RSD – Classification . 74
E.7.5 Category B uncertainties: Wind speed – RSD – Mounting . 74
E.7.6 Category B uncertainties: Wind speed – RSD – Flow variation . 74
E.7.7 Category B uncertainties: Wind speed – RSD – Monitoring test . 75
E.8 Category B uncertainties: Wind speed – REWS . 75
E.8.1 General . 75
E.8.2 Category B uncertainties: Wind speed – REWS – Wind speed
measurement over whole rotor . 75
E.8.3 Category B uncertainties: Wind speed – REWS – Wind veer . 76

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E.9 Category B uncertainties: Wind speed – Terrain . 77
E.9.1 General . 77
E.9.2 Category B uncertainties: Wind speed – Terrain – Pre-calibration . 77
E.9.3 Category B uncertainties: Wind speed – Terrain – Post-calibration . 78
E.9.4 Category B uncertainties: Wind speed – Terrain – Classification . 78
E.9.5 Category B uncertainties: Wind speed – Terrain – Mounting . 78
E.9.6 Category B uncertainties: Wind speed – Terrain – Data acquisition . 78
E.9.7 Category B uncertainties: Wind speed – Terrain – Lightning finial . 79
E.9.8 Category B uncertainties: Wind speed – Terrain – Change in correction
between adjacent bins . 79
E.9.9 Category B uncertainties: Wind speed – Terrain – Removal of WD
sensor . 79
E.9.10 Category B uncertainties: Wind speed – Terrain – Seasonal variation . 79
E.10 Category B uncertainties: Air density . 79
E.10.1 General . 79
E.10.2 Category B uncertainties: Air density – Temperature – Introduction . 80
E.10.3 Category B uncertainties: Air density – Temperature – Calibration . 81
E.10.4 Category B uncertainties: Air density – Temperature – Radiation
shielding . 81
E.10.5 Category B uncertainties: Air density – Temperature – Mounting . 81
E.10.6 Category B uncertainties: Air density – Temperature – Data acquisition. 81
E.10.7 Category B uncertainties: Air density – Pressure – Introduction . 81
E.10.8 Category B uncertainties: Air density – Pressure – Calibration . 82
E.10.9 Category B uncertainties: Air density – Pressure – Mounting . 83
E.10.10 Category B uncertainties: Air density – Pressure – Data acquisition . 83
E.10.11 Category B uncertainties: Air density – Relative humidity – Introduction . 83
E.10.12 Category B uncertainties: Air density – Relative humidity – Calibration . 84
E.10.13 Category B uncertainties: Air density – Relative humidity – Mounting . 84
E.10.14 Category B uncertainties: Air density – Relative humidity – Data
acquisition . 84
E.10.15 Category B uncertainties: Air density – Correction . 85
E.11 Category B uncertainties: Method . 85
E.11.1 General . 85
E.11.2 Category B uncertainties: Method – Wind conditions . 85
E.11.3 Category B uncertainties: Method – Seasonal effects . 90
E.11.4 Category B uncertainties: Method – Turbulence normalization (or the
lack thereof) . 91
E.11.5 Category B uncertainties: Method – Cold climate . 91
E.12 Category B uncertainties: Wind direction . 92
E.12.1 General . 92
E.12.2 Category B uncertainties: Wind direction – Vane or sonic . 92
E.12.3 Category B uncertainties: Wind direction – RSD . 93
E.13 Combining uncertainties . 94
E.13.1 General . 94
E.13.2 Combining Category B uncertainties in electric power (u ) . 95
P,i
E.13.3 Combining uncertainties in the wind speed measurement (u ) . 95
V,i
E.13.4 Combining uncertainties in the wind speed measurement from cup or
sonic (u ) . 95
VS,i
E.13.5 Combining uncertainties in the wind speed measurement from RSD
(u ) . 96
VR,i
IEC 61400-12-1:2022 © IEC 2022 – 5 –
E.13.6 Combining uncertainties in the wind speed measurement from REWS
u . 96
VREWS,i
E.13.7 Combining uncertainties in the wind speed measurement for REWS for
either a meteorological mast significantly above hub height or an RSD
with a lower-than-hub-height meteorological mast . 97
E.13.8 Combining uncertainties in the wind speed measurement for REWS for
a hub height meteorological mast plus RSD for shear using an absolute
wind speed . 99
E.13.9 Combining uncertainties in the wind speed measurement for REWS for
hub height meteorological mast RSD for shear using a relative wind
speed . 101
E.13.10 Combining uncertainties in the wind speed measurement from REWS
due to wind veer across the whole rotor u . 103
VREWS,veer,i
E.13.11 Combining uncertainties in the wind speed measurement from flow
distortion due to site calibration u . 107
VT,i
E.13.12 Combining uncertainties for the temperature measurement u . 108
T,i
E.13.13 Combining uncertainties for the pressure measurement u . 108
B,i
E.13.14 Combining uncertainties for the humidity measurement u . 109
RH,i
E.13.15 Combining uncertainties for the method related components u . 110
M,i
E.13.16 Combining uncertainties for the wind direction measurement with wind
vane or sonic anemometer u . 110
WV,i
E.13.17 Combining uncertainties for the wind direction measurement with RSD
u . 111
WR,i
E.13.18 Combined category B uncertainties. 111
E.13.19 Combined standard uncertainty – Power curve . 111
E.13.20 Combined standard uncertainty – Energy production . 111
E.14 Relevance of uncertainty components under specified conditions . 112
E.15 Reference tables . 112
Annex F (normative) Wind tunnel calibration procedure for anemometers . 116
Annex G (normative) Mounting of instruments on the meteorological mast . 117
Annex H (normative) Power performance testing of small wind turbines . 118
H.1 General . 118
H.2 Wind turbine system definition and installation . 118
H.3 Meteorological mast location . 119
H.4 Test equipment . 119
H.5 Measurement procedure . 120
H.6 Derived results . 121
H.7 Reporting . 121
H.8 Assessment of influence of wind turbines and obstacles at the test site . 121
H.9 Assessment of terrain at test site . 121
H.10 Site calibration procedure (refer to IEC 61400-12-3) . 122
Annex I (normative) Classification of cup and sonic anemometry . 123
Annex J (normative) Assessment of cup and sonic anemometry . 124
Annex K (normative) In-situ comparison of anemometers . 125
Annex L (normative) The application of remote sensing technology . 126
L.1 General . 126
L.2 Classification requirements specific to power performance tests . 127
L.3 Verification requirements specific to power performance tests . 127

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L.4 Uncertainty evaluation specific to power performance tests . 127
L.5 Additional checks specific to power performance tests . 128
L.5.1 Monitoring the performance of the remote sensing device at the
application site . 128
L.5.2 Identification of malfunctioning of the remote sensing device . 128
L.5.3 Consistency check of the assessment of the remote sensing device
systematic uncertainties . 128
L.5.4 In-situ test of the remote sensing device . 128
L.6 Other requirements specific to power performance testing . 128
Annex M (informative) Normalization of power curve data according to the turbulence
intensity . 131
M.1 General . 131
M.2 Turbulence normalization procedure . 131
M.3 Determination of the zero turbulence power curve . 133
M.4 Order of wind shear correction (normalization) and turbulence normalization . 139
M.5 Uncertainty of turbulence normalization or of power curves due to turbulence
effects . 139
Annex N (informative) Wind tunnel calibration procedure for wind direction sensors . 141
Annex O (informative) Power performance testing in cold climate . 142
O.1 Overview. 142
O.2 Recommendations . 142
O.2.1 General . 142
O.2.2 Sonic anemometers . 142
O.2.3 Cup anemometers . 142
O.3 Uncertainties. 143
O.4 Reporting . 143
Annex P (informative) Wind shear normalization procedure . 144
Annex Q (informative) Definition of the rotor equivalent wind speed under
consideration of wind veer . 146
Q.1 Overview. 146
Q.2 Definition of rotor equivalent wind speed under consideration of wind veer . 147
Q.3 Measurement of wind veer . 147
Q.4 Combined wind shear and wind veer normalization . 147
Annex R (informative) Uncertainty considerations for tests on multiple turbines . 148
Annex S (informative) Mast flow distortion correction for lattice masts . 152
Bibliography . 153

Figure 1 – Requirements as to distance of the wind measurement equipment and
maximum allowed measurement sectors . 28
Figure 2 – Wind shear measurement heights appropriate to measurement of rotor
equivalent wind speed . 33
Figure 3 – Wind shear measurement heights when no wind speed measurements
above hub height are available (for wind shear exponent determination only) . 34
Figure 4 – Process of application of the various normalizations . 38
Figure 5 – Presentation of example database: power performance test scatter plot
sampled at 1 Hz (mean values averaged over 10 min) . 49
Figure 6 – Presentation of example measured power curve . 49
Figure 7 – Presentation of example C curve. 50
P
IEC 61400-12-1:2022 © IEC 2022 – 7 –
Figure H.1 – Definition of hub height and meteorological mast location for vertical axis
wind turbines . 119
Figure L.1 – Example of permitted range of locations for measurement volume . 129
Figure M.1 – Process for obtaining a power curve for a specific turbulence intensity
(I ) . 132
ref
Figure M.2 – Process for obtaining the initial zero turbulence power curve parameters
from the measured data . 134
Figure M.3 – First approach for initial zero turbulence power curve . 134
Figure M.4 – Process for obtaining the theoretical zero-turbulence power curve from
the measured data . 136
Figure M.5 – Adjusted initial zero turbulence power curve (green) compared to first
approach (red) . 137
Figure M.6 – Process for obtaining the final zero-turbulence power curve from the
measured data . 138
Figure M.7 – Adjusted initial zero turbulence power curve (green) compared to final
zero turbulence power curve (black) . 138
Figure Q.1 – Wind profiles measured with lidar over flat terrain . 147

Table 1 – Overview of wind measurement configurations for power curve
measurements that meet the requirements of this document . 26
Table 2 – Wind speed measurement configurations (X indicates allowable
configuration) . 29
Table 3 – Example of REWS calculation . 40
Table 4 – Example of presentation of a measured power curve . 50
Table 5 – Example of presentation of estimated annual energy production . 52
Table D.1 – List of uncertainty components . 57
Table E.1 – Expanded uncertainties . 62
Table E.2 – List of category A and B uncertainties . 64
Table E.3 – Example of standard uncertainties due to absence of a wind shear
measurement . 87
Table E.4 – Example of standard uncertainties due to absence of a wind veer
measurement . 89
Table E.5 – Uncertainty contributions due to lack of upflow knowledge . 90
Table E.6 – Uncertainty contributions due to lack of turbulence knowledge . 90
Table E.7 – Suggested assumptions for correlations of measurement uncertainties
between different measurement heights . 98
Table E.8 – Suggested correlation assumptions for relative wind direction
measurement uncertainties at different measurement heights . 105
Table E.9 – Uncertainties from air density normalization . 112
Table E.10 – Sensitivity factors . 114
Table E.11 – Category B uncertainties . 115
Table H.1 – Battery bank voltage settings . 120
Table R.1 – List of correlated uncertainty components . 149

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND ENERGY GENERATION SYSTEMS –

Part 12-1: Power performance measurements
of electricity producing wind turbines

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 61400-12-1 has been prepared by IEC technical committee 88: Wind energy generation
systems. It is an International Standard.
This third edition of IEC 61400-12-1 is part of a structural revision that cancels and replaces
the performance standards IEC 61400-12-1:2017 and IEC 61400-12-2:2013. The structural
revision contains no technical changes with respect to IEC 61400-12-1:2017 and
IEC 61400-12-2:2013, but the parts that relate to wind measurements, measurement of site
calibration and assessment of obstacle and terrain have been extracted into separate
standards.
The purpose of the re-structure was to allow the future management and revision of the power
performance standards to be carried out more efficiently in terms of time and cost and to provide
a more logical division of the wind measurement requirements into a series of separate
standards which could be referred to by other use case standards in the IEC 61400 series and
subsequently maintained and developed by appropriate experts.

IEC 61400-12-1:2022 © IEC 2022 – 9 –
The text of this International Standard is based on the following documents:
Draft Report on voting
88/822/CDV 88/867/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 61400 series, published under the general title Wind energy
generation systems, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to th
...