SIST EN 61400-13:2016

Wind turbines - Part 13: Measurement of mechanical loads (IEC 61400-13:2015)

This part of the IEC 61400 describes the measurement of fundamental structural loads on
wind turbines for the purpose of the load simulation model validation. The standard prescribes
the requirements and recommendations for site selection, signal selection, data acquisition,
calibration, data verification, measurement load cases, capture matrix, post-processing,
uncertainty determination and reporting. Informative annexes are also provided to improve
understanding of testing methods.
The methods described in this document can also be used for mechanical loads
measurements for other purposes such as obtaining a measured statistical representation of
loads, direct measurements of the design loads, safety and function testing, or measurement
of component loads. If these methods are used for an alternative objective or used for an
unconventional wind turbine design, the required signals, measurement load cases, capture
matrix, and post processing methods should be evaluated and if needed adjusted to fit the
objective.
These methods are intended for onshore electricity-generating, horizontal-axis wind turbines
(HAWTs) with rotor swept areas of larger than 200 m2. However, the methods described may
be applicable to other wind turbines (for example, small wind turbines, ducted wind turbines,
vertical axis wind turbines).

Windenergieanlagen - Teil 13: Messung von mechanischen Lasten

Éoliennes - Partie 13: Mesurage des charges mécaniques

L'IEC 61400-13:2015(B) décrit le mesurage des charges structurelles fondamentales sur les éoliennes à des fins de validation des modèles de simulation de charges. La norme spécifie les exigences et recommandations concernant le choix du site, la sélection des signaux, l'acquisition des données, l'étalonnage, la vérification des données, les cas de charges de mesure, la matrice de capture, le post-traitement, la détermination de l'incertitude et les rapports d'essai. Des annexes informatives sont également fournies pour améliorer la compréhension des méthodes d'essai. Cette norme remplace l'IEC TS 61400-13 parue en 2001; elle constitue une révision technique, ainsi que la transposition d'une spécification technique en Norme internationale.

Vetrne turbine - 13. del: Meritve mehanskih obremenitev (IEC 61400-13:2015)

Ta del standarda IEC 61400 opisuje meritve temeljnih obremenitev konstrukcije pri vetrnih turbinah za namene preverjanja veljavnosti modela za simulacijo obremenitve. Standard predpisuje zahteve in priporočila za izbiro mesta uporabe, izbiro signalizacije, pridobivanje podatkov, umerjanje, preverjanje veljavnosti podatkov, primere meritvene obremenitve, metriko zajemanja, naknadno obdelavo, ugotavljanje negotovosti in poročanje. Vključeni so tudi informativni dodatki za boljše razumevanje preskusnih metod.
V tem dokumentu opisane metode se lahko uporabljajo tudi za meritve mehanskih obremenitev za druge namene, na primer za pridobivanje izmerjenih statističnih prikazov obremenitve, neposredne meritve projektnih obremenitev, preskušanje varnostnih in funkcionalnih lastnosti ali merjenje sestavnih obremenitev. Če se te metode uporabljajo za druge namene ali projektiranje nekonvencionalnih vetrnih turbin, je treba ovrednotiti potrebno signalizacijo, primere meritvene obremenitve, metriko zajemanja in metode naknadne obdelave ter jih po potrebi prilagoditi za te namene.
Te metode so namenjene za vetrne turbine z vodoravno osjo (HAWT) za proizvodnjo električne energije na kopnem z območji delovanja rotorja, katerih površina je večja kot 200 m2. Vendar opisane metode se lahko uporabljajo za druge vetrne turbine (npr. male vetrne turbine, kanalne vetrne turbine ali vetrne turbine z navpično osjo).

General Information

• Status: Published
• Publication Date: 04-May-2016
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: IEHT - Electrotechnics - Hydraulic turbins
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 14-Apr-2016
• Due Date: 19-Jun-2016
• Completion Date: 05-May-2016
• Ref Project: EN 61400-13:2016 - Wind turbines - Part 13: Measurement of mechanical loads

Relations

• Amended By: SIST EN 61400-13:2016/A1:2022 - Wind turbines - Part 13: Measurement of mechanical loads (IEC 61400-13:2015/AMD1:2021)
• Effective Date: 29-Dec-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61400-13:2016
01-junij-2016
Vetrne turbine - 13. del: Meritve mehanskih obremenitev (IEC 61400-13:2015)
Wind turbines - Part 13: Measurement of mechanical loads (IEC 61400-13:2015)
Ta slovenski standard je istoveten z: EN 61400-13:2016
ICS:
27.180 Vetrne elektrarne Wind turbine energy systems
SIST EN 61400-13:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61400-13:2016

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SIST EN 61400-13:2016


EUROPEAN STANDARD EN 61400-13

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2016
ICS 27.180

English Version
Wind turbines - Part 13: Measurement of mechanical loads
(IEC 61400-13:2015)
Éoliennes - Partie 13: Mesurage des charges mécaniques Windenergieanlagen - Teil 13: Messung von mechanischen
(IEC 61400-13:2015) Lasten
(IEC 61400-13:2015)
This European Standard was approved by CENELEC on 2016-01-25. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 61400-13:2016 E

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SIST EN 61400-13:2016
EN 61400-13:2016
European foreword
The text of document 88/511/CDV, future edition 1 of IEC 61400-13, prepared by IEC/TC 88 "Wind
turbines" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN 61400-13:2016.

The following dates are fixed:
(dop) 2016-10-25
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2019-01-25
standards conflicting with the
document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 61400-13:2015 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 61400-12-2 NOTE Harmonized as EN 61400-12-2.
IEC 61400-22 NOTE Harmonized as EN 61400-22.
2

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SIST EN 61400-13:2016
EN 61400-13:2016
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When 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 60050 Series International Electrotechnical Vocabulary - -
IEC 61400-1 2005 Wind turbines - EN 61400-1 2005
Part 1: Design requirements
IEC 61400-12-1 -  Wind turbines - EN 61400-12-1 -
Part 12-1: Power performance
measurements of electricity producing
wind turbines
ISO/IEC Guide 98-3 -  Uncertainty of measurement - - -
Part 3: Guide to the expression of
uncertainty in measurement

3

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SIST EN 61400-13:2016

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SIST EN 61400-13:2016




IEC 61400-13

®


Edition 1.0 2015-12




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Wind turbines –

Part 13: Measurement of mechanical loads




Éoliennes –

Partie 13: Mesurage des charges mécaniques
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.180 ISBN 978-2-8322-3087-9



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

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SIST EN 61400-13:2016
– 2 – IEC 61400-13:2015 © IEC 2015
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 11
4 Symbols, units and abbreviations . 14
5 General . 16
5.1 Document structure . 16
5.2 Safety during testing . 17
6 Test requirements . 17
6.1 General . 17
6.2 Test site requirements . 17
6.3 Measurement load cases . 17
6.3.1 General . 17
6.3.2 MLCs during steady-state operation . 18
6.3.3 MLCs during transient events . 18
6.3.4 MLCs for dynamic characterization . 19
6.3.5 Capture matrices . 20
6.4 Quantities to be measured . 23
6.4.1 General . 23
6.4.2 Load quantities . 23
6.4.3 Meteorological quantities . 25
6.4.4 Wind turbine operation quantities . 25
6.5 Turbine configuration changes . 26
7 Instrumentation . 27
7.1 Load quantities . 27
7.1.1 Types of sensors . 27
7.1.2 Choice of sensor location . 27
7.1.3 Measurement of blade root bending moments . 27
7.1.4 Blade bending moment distribution . 28
7.1.5 Blade torsion frequency/damping . 28
7.1.6 Measurement of rotor yaw and tilt moment . 28
7.1.7 Measurement of the rotor torque . 28
7.1.8 Measurement of tower base bending . 28
7.1.9 Tower top bending moments . 28
7.1.10 Tower mid bending moments . 29
7.1.11 Tower torque . 29
7.1.12 Tower top acceleration . 29
7.1.13 Pitch actuation loads (on hub side of pitch bearing) . 29
7.2 Meteorological quantities . 29
7.2.1 Measurement and installation requirements . 29
7.2.2 Icing potential . 29
7.2.3 Atmospheric stability . 29
7.3 Wind turbine operation quantities . 30
7.3.1 Electrical power . 30

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SIST EN 61400-13:2016
IEC 61400-13:2015 © IEC 2015 – 3 –
7.3.2 Rotor speed or generator speed . 30
7.3.3 Yaw misalignment . 30
7.3.4 Rotor azimuth angle. 30
7.3.5 Pitch position . 30
7.3.6 Pitch speed . 30
7.3.7 Brake moment . 30
7.3.8 Wind turbine status . 30
7.3.9 Brake status . 30
7.4 Data acquisition system . 31
7.4.1 General . 31
7.4.2 Resolution . 31
7.4.3 Anti-aliasing. 31
8 Determination of calibration factors . 31
8.1 General . 31
8.2 Calibration of load channels . 32
8.2.1 General . 32
8.2.2 Blade bending moments . 33
8.2.3 Main shaft moments . 33
8.2.4 Tower bending moments . 34
8.2.5 Tower torque . 34
8.3 Calibration of non-load channels . 35
8.3.1 Pitch angle . 35
8.3.2 Rotor azimuth angle. 35
8.3.3 Yaw angle. 35
8.3.4 Wind direction. 35
8.3.5 Pitch actuation loads . 35
8.3.6 Brake moment . 36
9 Data verification . 36
9.1 General . 36
9.2 Verification checks . 36
9.2.1 General . 36
9.2.2 Blade moments . 37
9.2.3 Main shaft . 38
9.2.4 Tower . 38
10 Processing of measured data . 39
10.1 General . 39
10.2 Fundamental load quantities . 39
10.3 Load quantities for larger turbines . 39
10.4 Wind speed trend detection . 39
10.5 Statistics . 40
10.6 Rainflow counting . 40
10.7 Cumulative rainflow spectrum . 40
10.8 Damage equivalent load. 40
10.9 Wind speed binning . 41
10.10 Power spectral density . 42
11 Uncertainty estimation . 42
12 Reporting. 42
Annex A (informative) Example co-ordinate systems . 46

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SIST EN 61400-13:2016
– 4 – IEC 61400-13:2015 © IEC 2015
A.1 General . 46
A.2 Blade co-ordinate system . 46
A.3 Hub co-ordinate system . 46
A.4 Nacelle co-ordinate system . 47
A.5 Tower co-ordinate system . 48
A.6 Yaw misalignment . 49
A.7 Cone angle and tilt angle . 49
A.8 Rotor azimuth angle . 50
A.9 Blade pitch angle . 50
Annex B (informative) Procedure for the evaluation of uncertainties in load
measurements on wind turbines . 51
B.1 List of symbols . 51
B.2 General procedure . 52
B.2.1 Standard uncertainty . 52
B.2.2 Analytical combination of standard uncertainties . 53
B.2.3 Total uncertainty . 54
B.3 Uncertainties of binned averaged values . 55
B.3.1 General . 55
B.3.2 Uncertainty of calibration and signal . 55
B.3.3 Uncertainty of the bin scatter . 55
B.3.4 Uncertainty of the x-axis quantity . 55
B.3.5 Uncertainty of bin averaged mean values . 55
B.4 Standard uncertainty of DEL and load spectra . 56
B.5 Examples of an uncertainty evaluation . 56
B.5.1 Example for analytical shunt calibration of tower torque . 56
B.6 Determination and use of calibration matrix . 63
B.6.1 Determination of the calibration matrix . 63
B.6.2 Use of the calibration matrix . 64
B.6.3 Time series . 65
Annex C (informative) Sample presentation of mechanical load measurements and
analysis . 67
C.1 General . 67
Annex D (informative)  Recommendations for offshore measurements . 79
Annex E (informative) Load model validation . 81
E.1 General . 81
E.2 Methods for loads comparison . 82
E.2.1 Statistical binning . 82
E.2.2 Spectral functions . 83
E.2.3 Fatigue spectra . 84
E.2.4 Point by point . 84
Annex F (informative) Methods for identification of wind speed trends . 86
F.1 List of symbols . 86
F.2 General . 86
F.3 Trend identification methods . 87
F.4 Ongoing procedure . 91
Annex G (informative) Data acquisition considerations . 92
G.1 Data acquisition system . 92
G.1.1 General . 92

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SIST EN 61400-13:2016
IEC 61400-13:2015 © IEC 2015 – 5 –
G.1.2 Resolution . 92
G.1.3 Sampling model and filtering . 93
G.1.4 Other considerations . 95
Annex H (informative) Load calibration . 96
H.1 General . 96
H.2 Gravity load calibration of the blade bending . 96
H.3 Analytical calibration of the tower bending moments . 97
H.4 External load calibration of the rotor torque . 98
Annex I (informative) Temperature drift . 99
I.1 General . 99
I.2 Known issues . 99
I.3 Recommendations . 100
Annex J (informative) Mechanical load measurements on vertical axis wind turbines . 101
J.1 General . 101
J.2 Terms and definitions . 101
J.3 Coordinate systems . 101
J.4 Quantities to be measured . 102
J.4.1 Fundamental loads . 102
J.5 Measurements . 103
J.5.1 Measurement of blade attachment bending moments . 103
J.5.2 Blade mid-span bending moment . 103
J.5.3 Blade modal frequency/damping . 103
J.5.4 Connecting strut bending moment. 103
J.5.5 Connecting strut axial force . 104
J.5.6 Connecting strut modal frequency/damping . 104
J.5.7 Rotor shaft torque . 104
J.5.8 Tower normal bending . 104
Bibliography . 105

Figure 1 – Fundamental wind turbine loads: tower base, rotor and blade loads . 24
Figure A.1 – Blade co-ordinate system . 46
Figure A.2 – Hub co-ordinate system . 47
Figure A.3 – Nacelle co-ordinate system . 48
Figure A.4 – Tower co-ordinate system . 48
Figure A.5 – Yaw misalignment . 49
Figure A.6 – Cone angle and tilt angle . 49
Figure B.1 – Explanation of used symbols . 61
Figure C.1 – Hub-height wind speed as a function of time . 67
Figure C.2 – Hub-height turbulence intensity as a function of hub-height wind speed . 68
Figure C.3 – Turbulence intensity trending as a function of hub-height wind speed . 68
Figure C.4 – Global capture matrix with all loads channels operating . 69
Figure C.5 – IEC example turbine at 9,1 m/s – Wind turbine operational and
meteorological quantities . 70
Figure C.6 – IEC example turbine at 9,1 m/s – Major load components . 71
Figure C.7 – 10-minute statistics for blade 1 root edge bending . 72
Figure C.8 – Power spectral density of blade 1 root edge bending . 73

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SIST EN 61400-13:2016
– 6 – IEC 61400-13:2015 © IEC 2015
Figure C.9 – Cumulative rainflow spectrum for blade 1 root edge bending during test
period . 75
Figure C.10 – IEC example turbine normal shutdown at 9,5 m/s – Wind turbine
operational and meteorological quantities . 77
Figure C.11 – IEC example turbine normal shutdown at 9,5 m/s – Major load
components . 78
Figure D.1 – Example of wave spectrum and monopile response . 79
Figure D.2 – Example of wave spectrum . 80
Figure E.1 – Measured data . 82
Figure E.2 – Simulated data . 82
Figure E.3 – Comparison of wind speed binned averaged 10 min. statistics . 82
Figure E.4 – Comparison of 1 Hz equivalent loads .
...