IEC 61400-50-1:2022

IEC 61400-50-1 ®
Edition 1.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Wind energy generation systems –
Part 50-1: Wind measurement – Application of meteorological mast, nacelle and
spinner mounted instruments
Systèmes de génération d'énergie éolienne
Partie 50-1: Mesurages du vent – Application d'instruments météorologiques
montés sur mât, nacelle et nez de rotor

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IEC 61400-50-1 ®
Edition 1.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Wind energy generation systems –

Part 50-1: Wind measurement – Application of meteorological mast, nacelle and

spinner mounted instruments
Systèmes de génération d'énergie éolienne

Partie 50-1: Mesurages du vent – Application d'instruments météorologiques

montés sur mât, nacelle et nez de rotor

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.180 ISBN 978-2-8322-5937-5

– 2 – IEC 61400-50-1:2022 © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Symbols, units and abbreviated terms . 11
5 General . 16
6 Classification of cup and sonic anemometry . 16
6.1 General . 16
6.2 Classification classes . 17
6.3 Influence parameter ranges . 17
6.4 Classification of cup and sonic anemometers . 17
6.5 Reporting format . 19
7 Assessment of cup and sonic anemometry . 19
7.1 General . 19
7.2 Measurements of anemometer characteristics . 19
7.2.1 Measurements in a wind tunnel for tilt angular response characteristics
of cup anemometers . 19
7.2.2 Wind tunnel measurements of directional characteristics of cup
anemometers . 21
7.2.3 Wind tunnel measurements of cup anemometer rotor torque
characteristics . 21
7.2.4 Wind tunnel measurements of step responses of cup anemometers . 22
7.2.5 Measurement of temperature induced effects on anemometer
performance . 23
7.2.6 Wind tunnel measurements of directional characteristics of sonic
anemometers . 24
7.3 A cup anemometer classification method based on wind tunnel and
laboratory tests and cup anemometer modelling . 25
7.3.1 Method . 25
7.3.2 Example of a cup anemometer model . 25
7.4 A sonic anemometer classification method based on wind tunnel tests and
sonic anemometer modelling . 32
7.5 Free field comparison measurements . 32
8 Wind tunnel calibration procedure for anemometers . 32
8.1 General requirements . 32
8.2 Requirements for the wind tunnel . 33
8.3 Instrumentation and calibration setup requirements . 35
8.4 Calibration procedure . 35
8.4.1 General procedure for cup and sonic anemometers . 35
8.4.2 Procedure for the calibration of sonic anemometers . 36
8.4.3 Determination of the wind speed at the anemometer position . 36
8.5 Data analysis . 37
8.6 Uncertainty analysis . 37
8.7 Reporting format . 38
8.8 Example uncertainty calculation . 39

9 In-situ comparison of anemometers . 42
9.1 General . 42
9.2 Prerequisite . 42
9.3 Analysis method . 42
9.4 Evaluation criteria . 43
10 Mounting of instruments on the meteorological mast . 45
10.1 General . 45
10.2 Single top-mounted anemometer. 46
10.3 Side-by-side top-mounted anemometers . 47
10.4 Side-mounted instruments . 49
10.4.1 General . 49
10.4.2 Tubular meteorological masts . 49
10.4.3 Lattice meteorological masts . 51
10.4.4 Flow distortion correction of side-mounted anemometers . 56
10.5 Lightning protection . 56
10.6 Mounting of other meteorological instruments . 56
10.7 Data acquisition system . 57
11 Uncertainty of wind speed measurement . 57
11.1 Category B uncertainties: Wind speed – Introduction . 57
11.2 Category B uncertainties: Wind speed – Hardware . 57
11.3 Category B uncertainties: Wind speed – Meteorological mast mounted
sensors . 57
11.3.1 General . 57
11.3.2 Pre-calibration . 58
11.3.3 Post-calibration . 58
11.3.4 Classification . 58
11.3.5 Mounting . 59
11.3.6 Lightning finial . 60
11.3.7 Data acquisition . 60
11.4 Category B uncertainties: Method – Cold climate .
...