IEC TS 61400-26-4:2024
(Main)Wind energy generation systems - Part 26-4: Reliability for wind energy generation systems
Wind energy generation systems - Part 26-4: Reliability for wind energy generation systems
IEC TS 61400-26-4:2024, which is a Technical Specification, specifies terms and information categories for identification and reporting of reliability metrics. The definitions are applicable to key components, any number of wind turbines, fleets of wind turbine types, a wind power station or a portfolio of wind power stations. The wind power station is made up of all WTGSs (Wind Turbine Generator Systems), functional services and balance of plant elements as seen from the point of common coupling.
This document provides guidelines regarding reliability methodologies with informative annexes regarding use.
It expands on the information model in IEC 61400-26-1, recognizing that availability and reliability are interrelated.
General Information
Standards Content (Sample)
IEC TS 61400-26-4 ®
Edition 1.0 2024-08
TECHNICAL
SPECIFICATION
Wind energy generation systems –
Part 26-4: Reliability for wind energy generation systems
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IEC TS 61400-26-4 ®
Edition 1.0 2024-08
TECHNICAL
SPECIFICATION
Wind energy generation systems –
Part 26-4: Reliability for wind energy generation systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.180 ISBN 978-2-8322-9458-1
– 2 – IEC TS 61400-26-4:2024 © IEC 2024
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions. 7
3.2 Abbreviated terms . 9
4 Preamble . 10
5 Reliability terms derived from the information model . 10
5.1 Information categories applied in reliability metrics . 10
5.2 Derivation of parameters for reliability metrics . 11
5.2.1 General . 11
5.2.2 Additional state information required . 12
5.2.3 Reliability terms derived from information categories – normative levels . 13
5.2.4 Reliability terms derived from the information model – optional levels . 16
5.2.5 Failure frequency and other aggregated reliability terms . 17
5.3 Applicability to WEGS, systems and components . 17
Annex A (informative) Illustrative examples. 18
A.1 Scenario 1 – Determination of MFDT, MRT, MTD, MTBF and MDT for
reporting reliability . 18
A.2 Scenario 2 – Incorporation of transitions to SCHEDULED MAINTENANCE
and PLANNED CORRECTIVE ACTION in the aggregated TTF counter stop
criteria . 19
A.3 Scenario 3 – SCHEDULED MAINTENANCE and PLANNED CORRECTIVE
ACTION not incorporated in the aggregated TTF counter stop criteria . 27
Annex B (informative) Reliability engineering considerations . 33
B.1 General . 33
B.2 Reliability . 34
B.3 Serviceability . 39
B.4 RAM . 43
Annex C (informative) Illustration of the approach used at component level . 44
Annex D (informative) Considerations on different needs for reporting reliability . 46
D.1 Advantages by introducing optional information categories . 46
D.2 Discussion of allocations for different stakeholder scenarios . 46
Bibliography . 51
Figure 1 – IEC 61400-26-1 information model . 12
Figure 2 – Reliability terms derived from the information model – normative levels . 15
Figure A.1 – Examples of transitions from IN SERVICE . 20
Figure A.2 – Illustration of the transition sequences in scenario 2 and 3 . 21
Figure B.1 – The information model as input provider for statistical analysis . 34
Figure B.2 – Reliability terms derived from the information model – including optional
levels . 37
Figure B.3 – Serviceability terms derived from the information model – including
optional levels . 42
Figure C.1 – Illustration of break-down to component level . 45
Figure D.1 – Example of system approach only considering OPERATIVE (IAO), NON-
OPERATIVE (IANO) and FORCE MAJEURE (IAFM) . 46
Figure D.2 – Example of a system approach leaving a mandatory category (IAOSPP) in
ambiguity . 47
Figure D.3 – Example of system approach only considering FORCED OUTAGE
(IANOFO and SUSPENDED (IANOS) as downtime . 48
Figure D.4 – Example of system approach defining only active production situations to
be 'system up-time', apart from requested shutdowns – to avoid ambiguity with the
definitions for mandatory levels, introduction of level 5 is advised . 49
Figure D.5 – Example of system approach defining only FULL PERFORMANCE
situations to be 'system up-time' – to avoid ambiguity with the definitions for mandatory
levels, introduction of level 5 is advised . 49
Figure D.6 – Example of system approach defining only FORCED OUTAGE,
SUSPENDED and FORCE MAJEURE situations to be 'system down-time' . 50
Table A.1 – Registration of FDT, RT, TD, TBF and DT . 18
Table A.2 – Scenario 2 . 22
Table A.3 – Scenario 3 . 28
– 4 – IEC TS 61400-26-4:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND ENERGY GENERATION SYSTEMS –
Part 26-4: Reliability for wind energy generation systems
FOREWORD
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IEC TS 61400-26-4 has been prepared by IEC technical committee 88: Wind energy generation
systems. It is a Technical Specification.
Throughout this document, mandatory information categories as defined in IEC 61400-26-1 are
written in capital letters (e.g. FULL PERFORMANCE, OUT OF ENVIRONMENTAL
SPECIFICATION).
The text of this Technical Specification is based on the following documents:
Draft Report on voting
88/954/DTS 88/1024/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs.
...
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