IEC 61400-12-1:2022

Wind energy generation systems - Part 12-1: Power performance measurements of electricity producing wind turbines

IEC 61400-12-1:2022 specifies a procedure for measuring the power performance characteristics of a single wind turbine and applies to the testing of wind turbines of all types and sizes connected to the electrical power network. In addition, this document defines a procedure to be used to determine the power performance characteristics of small wind turbines (as defined in IEC 61400-2) when connected to either the electric power network or a battery bank. This document defines a measurement methodology that requires the measured power curve and derived energy production figures to be supplemented by an assessment of uncertainty sources and their combined effects. 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.

Systèmes de génération d'énergie éolienne - Partie 12-1: Mesures de performance de puissance des éoliennes de production d'électricité

L'IEC 61400-12-1:2022 spécifie une procédure de mesure des caractéristiques de performance de puissance d'une éolienne simple et s'applique aux essais d'éoliennes, de tous types et de toutes tailles, raccordées au réseau électrique. En outre, le présent document définit une procédure à utiliser pour déterminer les caractéristiques de performance de puissance des petits aérogénérateurs (comme cela est défini dans l'IEC 61400-2) raccordés soit au réseau électrique, soit à un banc de batteries. Le présent document définit une méthodologie de mesure qui exige que les valeurs de la courbe de puissance mesurée et de la production d'énergie déduite soient complétées par une évaluation des sources d'incertitude et de leurs effets associés. La présente troisième édition de l’IEC 61400-12-1 fait partie d'une révision structurelle qui annule et remplace les normes de performance IEC 61400-12-1:2017 et IEC 61400‑12‑2:2013. Cette révision structurelle ne contient aucune modification technique par rapport à l'IEC 61400‑12-1:2017 et l'IEC 61400-12‑2:2013. Toutefois, les parties relatives aux mesurages du vent, au mesurage de l'étalonnage du site et à l'évaluation des obstacles et du terrain ont été extraites vers des normes distinctes.

General Information

• Status: Published
• Publication Date: 04-Sep-2022
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Drafting Committee: MT 12-1 - TC 88/MT 12-1
• Current Stage: PPUB - Publication issued
• Start Date: 26-Sep-2022
• Completion Date: 05-Sep-2022

Relations

• Replaces: IEC 61400-12-2:2013 - Wind turbines - Part 12-2: Power performance of electricity-producing wind turbines based on nacelle anemometry
• Effective Date: 05-Sep-2023
• Replaces: IEC 61400-12-1:2017 - Wind energy generation systems - Part 12-1: Power performance measurements of electricity producing wind turbines
• Effective Date: 05-Sep-2023

Standards Content (Sample)

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

IEC 61400-12-1:2022-09(en-fr)

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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




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 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

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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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– 4 – IEC 61400-12-1:2022 © IEC 2022
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

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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 .
...