IEC TS 61400-13:2001

TECHNICAL IEC
SPECIFICATION
TS 61400-13
First edition
2001-06
Wind turbine generator systems –
Part 13:
Measurement of mechanical loads
Aérogénérateurs –
Partie 13: Mesure des charges mécaniques

Reference number
IEC/TS 61400-13:2001(E)
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TECHNICAL IEC
SPECIFICATION
TS 61400-13
First edition
2001-06
Wind turbine generator systems –
Part 13:
Measurement of mechanical loads
Aérogénérateurs –
Partie 13: Mesure des charges mécaniques

 IEC 2001  Copyright - all rights reserved
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– 2 – TS 61400-13 © IEC:2001(E)

CONTENTS
FOREWORD . 4

INTRODUCTION .6

Clause
1 General. 7

1.1 Scope and object . 7

1.2 Normative references. 7
1.3 Definitions . 7
1.4 Symbols, units and abbreviations. 9
2 Safety during testing . 10
3 Load measurement programmes . 11
3.1 General. 11
3.2 Measurement load cases (MLCs). 11
3.3 Quantities to be measured . 16
4 Measurement techniques . 19
4.1 General. 19
4.2 Load quantities . 19
4.3 Meteorological quantities . 23
4.4 Wind turbine operation parameters . 24
4.5 Data acquisition . 24
4.6 Sensor accuracy and resolution . 25
5 Processing of measured data. 26
5.1 General. 26
5.2 Data validation. 26
5.3 Time series and load statistics . 27
5.4 Load spectra. 28
5.5 Equivalent loads . 29
6 Reporting. 30
Annex A (informative) Co-ordinate systems. 32

Annex B (informative) Procedure for the evaluation of uncertainties in load measurements
on wind turbines . 37
Annex C (informative) Sample presentation of mechanical load measurements and analysis. 47
Annex D (informative) Extrapolation to other turbulence conditions . 64
Bibliography . 69

TS 61400-13 © IEC:2001(E) – 3 –

Figure 1 – Fundamental wind turbine loads: tower base, tower top, rotor and blades. 18

Figure A.1 – Blade co-ordinate system . 32

Figure A.2 – Hub co-ordinate system. 33

Figure A.3 – Nacelle co-ordinate system . 33

Figure A.4 – Tower co-ordinate system . 34

Figure A.5 – Yaw misalignment . 35

Figure A.6 – Cone angle and tilt angle. 35

Figure C.1 – Meteorological quantities record time series. 49
Figure C.2 – Wind turbine operational quantities record time series . 50
Figure C.3 – Wind turbine mechanical load time series (first minute of record) . 51
Figure C.4 – Wind turbine mechanical load time series (first minute of record) . 52
Figure C.5 – Azimuthal variation of blade and shaft loads . 53
Figure C.6 – Frequency spectral density functions for blade, rotor and tower loads . 54
Figure C.7 – Fatigue spectra for blade, rotor and tower loads. 55
Figure C.8 – Meteorological quantities statistics. 56
Figure C.9 – Wind turbine operational quantities statistics
.................................................... 57
Figure C.10 – Blade-root flapwise and lead-lag bending-moment statistics. 58
Figure C.11 – Rotor mechanical load statistics . 59
Figure C.12 – Tower load statistics
...................................................................................... 60
Figure C.13 – Fatigue equivalent loads for blade root bending moments and shaft torque . 61
Figure C.14 – Fatigue equivalent loads for rotor yaw and tilt moments and tower torsion
...... 62
Figure C.15 – Fatigue equivalent loads for tower base bending moment
............................... 63
Figure D.1 – Linear extrapolation of fatigue spectra to higher turbulence intensity levels. 65
Figure D.2 – Turbulence intensity versus wind speed . 67
Figure D.3 – Mean amplitude (1st statistical moment) of flap-bending moment
versus wind speed. 67
Figure D.4 – Coefficient of variation (2nd statistical moment) of flap-bending moment
versus wind speed. 68
Figure D.5 – Skewness (3rd statistical moment) of flap-bending moment versus wind speed . 68
Figure D.6 – Measured and extrapolated spectra of flap-bending moment ranges . 68
Table 1 – MLCs during steady-state operation related to the DLCs defined in IEC 61400-1. 12

Table 2 – Measurement of transient load cases related to the DLCs defined in IEC 61400-1. 13
Table 3 – Capture matrix for normal power production. 14
Table 4 – Capture matrix for power production plus occurrence of fault . 15
Table 5 – Capture matrix for parked condition . 15
Table 6 – Capture matrix for normal transient events. 15
Table 7 – Capture matrix for other than normal transient events. 16
Table 8 – Wind turbine fundamental load quantities. 16
Table 9 – Meteorological quantities . 17
Table 10 – Wind turbine operation quantities. 17
Table 11 – Target standard uncertainties for the various non-load quantities. 25
Table C.1 – Capture matrix. 47
Table C.2 – Record brief statistical description. 48

– 4 – TS 61400-13 © IEC:2001(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
WIND TURBINE GENERATOR SYSTEMS –

Part 13: Measurement of mechanical loads

FOREWORD
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future but no immediate possibility of an agreement on an International Standard.

Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 61400-13, which is a technical spe
...