EN IEC 61400-3-2:2025

Wind energy generation systems - Part 3-2: Design requirements for floating offshore wind turbines

IEC 61400-3-2:2025 specifies requirements for assessment of the external conditions at a floating offshore wind turbine (FOWT) site and specifies essential design requirements to ensure the engineering integrity of FOWTs. Its purpose is to provide an appropriate level of protection against damage from all anticipated hazards during the planned lifetime. This document focuses on the engineering integrity of the structural components of a FOWT but is also concerned with subsystems such as control and protection mechanisms, internal electrical systems and mechanical systems. This first edition cancels and replaces IEC TS 61400-3-2, published in 2019. This edition includes the following significant technical changes with respect to IEC TS 61400‑3-2: a) The relevant contents of IEC 61400-3-1 have been migrated into IEC 61400-3-2, making IEC 61400-3-2 a self-standing document that does not have to be read directly in conjunction with IEC 61400-3-1. b) Several modifications have been made regarding metocean conditions in Clause 6 considering the nature of FOWT and the offshore site where FOWT will be installed, including: (1) the importance of wave directional spreading has been highlighted as it may result in larger loads for FOWT, including the addition of the new informative Annex O and Annex P and (2) the characteristic of swell has been explained, which may be relevant for some FOWT projects, including the addition of new informative Annex R regarding the characteristic of swell. c) Subclauses 7.1, 7.2, 7.3, 7.4 and 7.5 have been changed to include a revised DLC table and its related descriptions, including amongst others updated requirements on directionality, wave conditions, redundancy check and damage stability cases, and a robustness check case; further updates are made related to guidance and necessities provided on load calculations and simulation requirements. d) Subclause 7.6 has been updated with guidance on fatigue assessment along with clarifications on serviceability analysis and the applicable material for WSD; related Annex L has been updated and a new Annex M has been added for clarification of the safety factors and load and load effect approach for floating substructures e) The concept of floater control system that will interact with the wind turbine controller has been introduced in Clause 8. f) Clause 11 has been renamed from "Foundation and substructure design" to "Anchor design" and requirements for the transient conditions have been added. g) A more detailed clause regarding concrete design has been added to Clause 16 together with an informative Annex Q. h) Clause 15 has been updated with the aim to improve ease of use, using experience from oil and gas and considering unique wind turbine characteristics; updates included guidance for TLPs, damage stability, dynamic stability, testing and the addition for Annex S regarding how to analyse collision probability.

Windenergieanlagen - Teil 3-2: Auslegungsanforderungen für schwimmende Windenergieanlagen auf offener See

Systèmes de génération d’énergie éolienne - Partie 3-2: Exigences de conception des éoliennes en mer flottantes

l'IEC 61400-3-2:2025 spécifie des exigences d'évaluation des conditions externes sur un site d'éoliennes en mer flottantes (FOWT), ainsi que les exigences essentielles de conception, afin d'assurer l'intégrité technique des FOWT. Elle a pour objet de fournir un niveau de protection approprié contre les dommages provoqués par tous les dangers prévus pendant la durée de vie prévue. Le présent document se concentre sur l'intégrité technique des composants structurels d'une FOWT, mais concerne également les sous-systèmes, tels que les mécanismes de commande et de protection, les systèmes électriques internes et les systèmes mécaniques. Cette première édition annule et remplace l'IEC TS 61400-3-2 parue en 2019. Cette première édition annule et remplace l'IEC TS 61400-3-2 parue en 2019. a) le contenu pertinent de l'IEC 61400-3-1 a été transféré dans l'IEC 61400-3-2, faisant de l'IEC 61400-3-2 un document autonome qui ne doit pas être lu directement conjointement avec l'IEC 61400-3-1; b) plusieurs modifications ont été apportées concernant les conditions océano-météorologiques spécifiées à l'Article 6 en prenant en compte la nature de la FOWT et le site en mer sur lequel la FOWT est installée, notamment: (1) l'importance de la propagation directionnelle des vagues a été soulignée, car elle peut entraîner des charges plus importantes pour la FOWT, y compris l'ajout des nouvelles Annexe O et Annexe P informatives, et (2) la caractéristique de la houle a été expliquée, ce qui peut être pertinent pour certains projets FOWT, y compris l'ajout d'une nouvelle Annexe R informative concernant la caractéristique de la houle; c) les 7.1, 7.2, 7.3, 7.4 et 7.5 ont été modifiés pour inclure un tableau de DLC (Design Load Case, cas de charge pour la conception) révisé et ses descriptions associées, y compris, entre autres, des exigences mises à jour sur la directionnalité, les conditions de vagues, les cas de contrôle de redondance et de stabilité après avarie, et un cas de contrôle de solidité; d'autres mises à jour sont effectuées concernant les recommandations et les éléments nécessaires fournis sur les calculs de charge et les exigences de simulation; d) le 7.6 a été mis à jour avec des recommandations relatives à l'évaluation de la fatigue ainsi que des clarifications sur l'analyse de l'aptitude au service et le matériel applicable pour le WSD. L'Annexe L connexe a été mise à jour et une nouvelle Annexe M a été ajoutée pour la clarification des facteurs de sécurité et l'approche de charge et d'effet de charge pour les sous-structures flottantes; e) le concept de système de commande de flotteur qui interagit avec le régulateur de l'éolienne a été introduit à l'Article 8; f) l'Article 11 "Conception de la fondation et de la sous-structure" a été renommé en "Conception des ancres" et des exigences relatives aux conditions transitoires ont été ajoutées; g) un article plus détaillé sur la conception du béton a été ajouté à l'Article 16 ainsi qu'une Annexe Q informative; h) l'Article 15 a été mis à jour dans le but d'améliorer la facilité d'utilisation, en utilisant l'expérience du pétrole et du gaz et en prenant en compte les caractéristiques uniques des éoliennes. Les mises à jour comprenaient des recommandations pour les TLP, la stabilité après avarie, la stabilité dynamique, les essais et l'ajout de l'Annexe S concernant la manière d'analyser la probabilité de collision.

Sistemi za proizvodnjo energije na veter - 3-2. del: Izvedbene zahteve za plavajoče vetrne turbine

General Information

• Status: Not Published
• Publication Date: 27-Feb-2025
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: CLC/TC 88 - Wind turbines
• Drafting Committee: IEC/TC 88 - IEC_TC_88
• Current Stage: 5060 - Voting results sent to TC, SR - Formal Approval
• Start Date: 26-Jul-2024
• Due Date: 26-Jul-2024
• Completion Date: 26-Jul-2024
• Ref Project: kSIST FprEN IEC 61400-3-2:2024 - Wind energy generation systems - Part 3-2: Design requirements for floating offshore wind turbines

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN IEC 61400-3-2:2023
01-februar-2022
Sistemi za proizvodnjo energije na veter - 3-2. del: Izvedbene zahteve za plavajoče
vetrne turbine
Wind energy generation systems - Part 3-2: Design requirements for floating offshore
wind turbines
Ta slovenski standard je istoveten z: prEN IEC 61400-3-2:2022
ICS:
27.180 Vetrne elektrarne Wind turbine energy systems
oSIST prEN IEC 61400-3-2:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN IEC 61400-3-2:2023
oSIST prEN IEC 61400-3-2:2023
88/917/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61400-3-2 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-12-09 2023-03-03
SUPERSEDES DOCUMENTS:
88/846/CD, 88/915/CC
IEC TC 88 : WIND ENERGY GENERATION SYSTEMS
SECRETARIAT: SECRETARY:
Denmark Mrs Christine Weibøl Bertelsen
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
TC 114
Other TC/SCs are requested to indicate their interest, if any, in
this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for Vote
(CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
TITLE:
Wind energy generation systems – Part 3-2: Design requirements for floating offshore wind turbines
PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:
In order to assist MT 3-2 when sorting and compiling the given comments on the CDV document, it is of great importance
that all comments given in the comments form refer to both clause and line numbers in the CDV document.
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

oSIST prEN IEC 61400-3-2:2023
88/917/CDV − 2 − IEC CDV 61400-3-2 © IEC 2022
CONTENTS
CONTENTS . 1
FOREWORD . 8
INTRODUCTION . 11
1 Scope . 12
2 Normative references . 13
3 Terms and definitions . 14
4 Symbols and abbreviated terms . 25
4.1 Symbols and units. 25
4.2 Abbreviations . 26
5 Principal elements . 27
5.1 General . 27
5.2 Design methods . 28
5.3 Exposure level for FOWT . 29
5.4 Safety classes for RNA and tower . 29
5.5 Quality assurance . 30
5.6 Rotor–nacelle assembly markings . 30
5.7 Support structure markings . 30
6 External conditions – definition and assessment . 30
6.1 General . 30
6.2 Wind turbine classes . 31
6.3 Definition of external conditions at a FOWT site . 31
6.3.1 General . 31
6.3.2 Wind conditions . 32
6.3.3 Marine conditions . 32
6.3.4 Electrical power network conditions . 40
6.3.5 Other environmental conditions . 40
6.4 Assessment of external conditions at a FOWT site . 41
6.4.1 General . 41
6.4.2 The metocean database . 41
6.4.3 Assessment of wind conditions . 42
6.4.4 Assessment of marine conditions . 44
6.4.5 Assessment of other environmental conditions . 48
6.4.6 Assessment of electrical network conditions . 49
6.4.7 Assessment of soil conditions . 49
7 Structural design . 50
7.1 General . 50
7.2 Design methodology . 51
7.3 Loads. 51
7.3.1 General . 51
7.3.2 Gravitational and inertial loads . 51
7.3.3 Aerodynamic loads . 51
7.3.4 Actuation loads . 51
7.3.5 Hydrodynamic loads . 52

oSIST prEN IEC 61400-3-2:2023
IEC CDV 61400-3-2 © IEC 2022 − 3 − 88/917/CDV
7.3.6 Sea/lake ice loads . 52
7.3.7 Other loads . 53
7.4 Design situations and load cases . 53
7.4.1 General . 53
7.4.2 Power production (DLC 1.1 to 1.6) . 62
7.4.3 Power production plus occurrence of fault or loss of electrical network
connection (DLC 2.1 – 2.6) . 64
7.4.4 Start up (DLC 3.1 to 3.3). 66
7.4.5 Normal shutdown (DLC 4.1 to 4.3) . 67
7.4.6 Emergency stop (DLC 5.1) . 67
7.4.7 Parked (standstill or idling) (DLC 6.1 to 6.5) . 67
7.4.8 Parked plus fault conditions (DLC 7.1 to 7.2) . 69
7.4.9 Transport, assembly, maintenance and repair (DLC 8.1 to 8.4) . 70
7.4.10 Redundancy check and damage stability (DLC F1.1 to F2.3) . 73
7.5 Load and load effect calculations . 74
7.5.1 General . 74
7.5.2 Relevance of hydrodynamic loads . 75
7.5.3 Calculation of hydrodynamic loads . 75
7.5.4 Calculation of sea/lake ice loads . 76
7.5.5 Overall damping assessment for support structure response evaluations . 76
7.5.6 Simulation requirements . 77
7.5.7 Other requirements . 80
7.6 Ultimate limit state analysis. 81
7.6.1 Method . 81
7.6.2 Ultimate strength analysis . 84
7.6.3 Fatigue analysis . 85
7.6.4 Special partial safety factors . 86
7.6.5 Working stress design method . 86
7.6.6 Serviceability analysis . 87
8 Control system . 87
9 Mechanical systems . 88
10 Electrical system . 89
11 Anchor design . 90
12 Assembly, transport and installation . 90
12.1 General . 90
12.2 Planning . 90
12.3 Environmental conditions . 91
12.4 Documentation . 91
12.5 Transport, receiving, handling and storage . 91
13 Commissioning, operation and maintenance . 91
13.1 General . 91
13.2 Design requirements for safe operation, inspection and maintenance . 91
13.3 Commissioning . 92
13.3.1 General . 93
13.3.2 Energization . 93
13.3.3 Commissioning tests . 93

oSIST prEN IEC 61400-3-2:2023
88/917/CDV − 4 − IEC CDV 61400-3-2 © IEC 2022
13.3.4 Records . 93
13.3.5 Post commissioning activities . 93
13.4 Operator’s instruction manual . 93
13.4.1 General . 93
13.4.2 Instructions for operations and maintenance record . 94
13.4.3 Instructions for unscheduled automatic shutdown . 94
13.4.4 Instructions for diminished reliability . 94
13.4.5 Work procedures plan . 94
13.4.6 Emergency procedures plan . 95
13.5 Maintenance manual . 95
14 Stationkeeping systems . 96
14.1 General .
...