IEC 61400-3-1:2019

Wind energy generation systems - Part 3-1: Design requirements for fixed offshore wind turbines

IEC 61400-3-1:2019 outlines the minimum design requirements for fixed offshore wind turbines and is not intended for use as a complete design specification or instruction manual.
Several different parties may be responsible for undertaking the various elements of the design, manufacture, assembly, installation, erection, commissioning, operation and maintenance of an offshore wind turbine and for ensuring that the requirements of this document are met. The division of responsibility between these parties is a contractual matter and is outside the scope of this document.
This edition cancels and replaces the first edition of IEC 61400-3 published in 2009. This edition includes the following significant technical changes with respect to the first edition of IEC 61400-3:
a) The design load table has been revised to simplify the approach to waves, both for several gust cases with the Normal Sea State, and for a number of cases with the Extreme Sea State. The guidance for load calculations has been altered accordingly;
c) For load safety factors reference is now made directly to IEC 61400-1;
d) Control system has been aligned with the latest updates in IEC 61400-1;
e) Wave spectra has been replaced by a reference to ISO 19901-1;
f) The annex on ice loading has been revised and updated
g) Two informative annexes concerning tropical cyclones have been introduced
h) Other parts of the text have been aligned with IEC 61400-1

Systèmes de génération d’énergie éolienne - Partie 3-1: Exigences de conception des éoliennes en mer fixes

l'IEC 61400-3-1:2019 spécifie des exigences complémentaires d'évaluation des conditions externes sur un site d'éoliennes en mer, ainsi que les exigences essentielles de conception, afin d'assurer l'intégrité technique des éoliennes en mer fixes. Elle a pour objet de fournir un niveau de protection approprié contre les dommages causés par tous les dangers pendant la durée de vie prévue.
Le présent document se concentre sur l'intégrité technique des éléments de structure d'une éolienne en mer, mais concerne également les sous-systèmes, tels que les mécanismes de commande et de protection, les systèmes électriques internes et les systèmes mécaniques.
Cette édition annule et remplace la première édition de l'IEC 61400-3 parue en 2009. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à la première édition de l'IEC 61400-3:
a) Le tableau des charges de conception a été révisé afin de simplifier l'approche par vagues, à la fois pour plusieurs cas de rafales avec l'état de mer normale et pour de nombreux cas avec l'état de mer extrême. Les recommandations concernant les calculs de charge ont été modifiées en conséquence;
b) Pour les facteurs de sécurité de charge, il est désormais fait directement référence à l'IEC 61400-1;
c) Le système de commande a été aligné sur les dernières mises à jour de l'IEC 61400-1;
d) La première édition consacrée aux spectres d'ondes a été remplacée par une référence à l'ISO 19901-1;
e) L'annexe consacrée aux surcharges de glace a été révisée et mise à jour
f) Deux annexes informatives concernant les cyclones tropicaux ont été introduites:
g) Les autres parties du texte ont été alignées sur l'IEC 61400-1.

General Information

• Status: Published
• Publication Date: 04-Apr-2019
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Drafting Committee: WG 3 - TC 88/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 22-Mar-2019
• Completion Date: 05-Apr-2019

Relations

• Replaces: IEC 61400-3:2009 - Wind turbines - Part 3: Design requirements for offshore wind turbines
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61400-3-1 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
colour
inside
Wind energy generation systems –
Part 3-1: Design requirements for fixed offshore wind turbines

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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About the IEC
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International Standards for all electrical, electronic and related technologies.

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IEC 61400-3-1 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
colour
inside
Wind energy generation systems –

Part 3-1: Design requirements for fixed offshore wind turbines

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.180 ISBN 978-2-8322-6600-7

– 2 – IEC 61400-3-1:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Symbols and abbreviated terms . 19
4.1 Symbols and units. 19
4.2 Abbreviations . 20
5 Principal elements . 21
5.1 General . 21
5.2 Design methods . 21
5.3 Safety classes . 22
5.4 Quality assurance . 22
5.5 Rotor–nacelle assembly markings . 23
6 External conditions – definition and assessment . 23
6.1 General . 23
6.2 Wind turbine classes . 24
6.3 Definition of external conditions at an offshore wind turbine site . 24
6.3.1 General . 24
6.3.2 Wind conditions . 25
6.3.3 Marine conditions . 25
6.3.4 Electrical power network conditions . 32
6.3.5 Other environmental conditions . 32
6.4 Assessment of external conditions at an offshore wind turbine site . 33
6.4.1 General . 33
6.4.2 The metocean database . 33
6.4.3 Assessment of wind conditions . 34
6.4.4 Assessment of marine conditions . 36
6.4.5 Assessment of other environmental conditions . 40
6.4.6 Assessment of electrical network conditions . 41
6.4.7 Assessment of soil conditions . 41
7 Structural design . 42
7.1 General . 42
7.2 Design methodology . 42
7.3 Loads. 42
7.3.1 General . 42
7.3.2 Gravitational and inertial loads . 42
7.3.3 Aerodynamic loads . 43
7.3.4 Actuation loads . 43
7.3.5 Hydrodynamic loads . 43
7.3.6 Sea/lake ice loads . 43
7.3.7 Other loads . 44
7.4 Design situations and load cases . 44
7.4.1 General . 44
7.4.2 Power production (DLC 1.1 to 1.6) . 50

7.4.3 Power production plus occurrence of fault or loss of electrical network
connection (DLC 2.1 – 2.5) . 51
7.4.4 Start up (DLC 3.1 to 3.3). 53
7.4.5 Normal shutdown (DLC 4.1 to 4.2) . 54
7.4.6 Emergency stop (DLC 5.1) . 54
7.4.7 Parked (standstill or idling) (DLC 6.1 to 6.4) . 55
7.4.8 Parked plus fault conditions (DLC 7.1 to 7.2) . 56
7.4.9 Transport, assembly, maintenance and repair (DLC 8.1 to 8.4) . 57
7.4.10 Sea/lake ice design load cases . 60
7.5 Load and load effect calculations . 61
7.5.1 General . 61
7.5.2 Relevance of hydrodynamic loads . 61
7.5.3 Calculation of hydrodynamic loads . 62
7.5.4 Calculation of sea/lake ice loads . 62
7.5.5 Overall damping assessment for support structure response evaluations . 62
7.5.6 Simulation requirements . 64
7.5.7 Other requirements . 65
7.6 Ultimate limit state analysis. 66
7.6.1 Method . 66
7.6.2 Ultimate strength analysis . 68
7.6.3 Fatigue failure . 68
7.6.4 Special partial safety factors . 69
7.6.5 Assessment of cyclic loading for foundation assessment . 69
8 Control system . 69
9 Mechanical systems . 70
10 Electrical system . 70
11 Foundation and substructure design . 70
12 Assembly, installation and erection . 71
12.1 General . 71
12.2 Planning . 72
12.3 Installation conditions . 72
12.4 Site access . 72
12.5 Environmental conditions . 73
12.6 Documentation . 73
12.7 Receiving, handling and storage . 73
12.8 Support structure systems . 73
12.9 Assembly of offshore wind turbine . 73
12.10 Erection of offshore wind turbine . 74
12.11 Fasteners and attachments . 74
12.12 Cranes, hoists and lifting equipment . 74
13 Commissioning, operation and maintenance . 74
13.1 General . 74
13.2 Design requirements for safe operation, inspection and maintenance . 75
13.3 Instructions concerning commissioning . 76
13.3.1 General . 76
13.3.2 Energization . 76
13.3.3 Commissioning tests . 76
13.3.4 Records . 76

– 4 – IEC 61400-3-1:2019 © IEC 2019
13.3.5 Post commissioning activities . 76
13.4 Operator’s instruction manual . 76
13.4.1 General . 76
13.4.2 Instr
...

IEC 61400-3-1 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Wind energy generation systems –
Part 3-1: Design requirements for fixed offshore wind turbines

Systèmes de génération d'énergie éolienne –
Partie 3-1: Exigences de conception des éoliennes en mer fixes

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

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CH-1211 Geneva 20 www.iec.ch
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
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once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
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If you wish to give us your feedback on this publication or CISPR.

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IEC 61400-3-1 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Wind energy generation systems –

Part 3-1: Design requirements for fixed offshore wind turbines

Systèmes de génération d'énergie éolienne –

Partie 3-1: Exigences de conception des éoliennes en mer fixes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.180 ISBN 978-2-8322-7609-9

– 2 – IEC 61400-3-1:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Symbols and abbreviated terms . 19
4.1 Symbols and units. 19
4.2 Abbreviations . 20
5 Principal elements . 21
5.1 General . 21
5.2 Design methods . 21
5.3 Safety classes . 22
5.4 Quality assurance . 22
5.5 Rotor–nacelle assembly markings . 23
6 External conditions – definition and assessment . 23
6.1 General . 23
6.2 Wind turbine classes . 24
6.3 Definition of external conditions at an offshore wind turbine site . 24
6.3.1 General . 24
6.3.2 Wind conditions . 25
6.3.3 Marine conditions . 25
6.3.4 Electrical power network conditions . 32
6.3.5 Other environmental conditions . 32
6.4 Assessment of external conditions at an offshore wind turbine site . 33
6.4.1 General . 33
6.4.2 The metocean database . 33
6.4.3 Assessment of wind conditions . 34
6.4.4 Assessment of marine conditions . 36
6.4.5 Assessment of other environmental conditions . 40
6.4.6 Assessment of electrical network conditions . 41
6.4.7 Assessment of soil conditions . 41
7 Structural design . 42
7.1 General . 42
7.2 Design methodology . 42
7.3 Loads. 42
7.3.1 General . 42
7.3.2 Gravitational and inertial loads . 42
7.3.3 Aerodynamic loads . 43
7.3.4 Actuation loads . 43
7.3.5 Hydrodynamic loads . 43
7.3.6 Sea/lake ice loads . 43
7.3.7 Other loads . 44
7.4 Design situations and load cases . 44
7.4.1 General . 44
7.4.2 Power production (DLC 1.1 to 1.6) . 50

7.4.3 Power production plus occurrence of fault or loss of electrical network
connection (DLC 2.1 – 2.5) . 51
7.4.4 Start up (DLC 3.1 to 3.3). 53
7.4.5 Normal shutdown (DLC 4.1 to 4.2) . 54
7.4.6 Emergency stop (DLC 5.1) . 54
7.4.7 Parked (standstill or idling) (DLC 6.1 to 6.4) . 55
7.4.8 Parked plus fault conditions (DLC 7.1 to 7.2) . 56
7.4.9 Transport, assembly, maintenance and repair (DLC 8.1 to 8.4) . 57
7.4.10 Sea/lake ice design load cases . 60
7.5 Load and load effect calculations . 61
7.5.1 General . 61
7.5.2 Relevance of hydrodynamic loads . 61
7.5.3 Calculation of hydrodynamic loads . 62
7.5.4 Calculation of sea/lake ice loads . 62
7.5.5 Overall damping assessment for support structure response evaluations . 62
7.5.6 Simulation requirements . 64
7.5.7 Other requirements . 65
7.6 Ultimate limit state analysis. 66
7.6.1 Method . 66
7.6.2 Ultimate strength analysis . 68
7.6.3 Fatigue failure . 68
7.6.4 Special partial safety factors . 69
7.6.5 Assessment of cyclic loading for foundation assessment . 69
8 Control system . 69
9 Mechanical systems . 70
10 Electrical system . 70
11 Foundation and substructure design . 70
12 Assembly, installation and erection . 71
12.1 General .
...