IEC TS 61400-26-2:2014
(Main)Wind turbines - Part 26-2: Production-based availability for wind turbines
Wind turbines - Part 26-2: Production-based availability for wind turbines
IEC TS 61400-26-2:2014 provides a framework from which production-based performance indicators of a wind turbine generator system can be derived. It unambiguously describes how data is categorised and provides examples of how the data can be used to derive performance indicators. The approach of this part of IEC 61400 is to expand the time allocation model, introduced in IEC TS 61400-26-1, with two additional layers for recording of the actual energy production and potential energy production associated with the concurrent time allocation. This document also includes informative annexes with:
- examples of determination of lost production,
- examples of algorithms for production-based indicators,
- examples of other performance indicators,
- examples of application scenarios.
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Standards Content (Sample)
IEC TS 61400-26-2
®
Edition 1.0 2014-06
TECHNICAL
SPECIFICATION
colour
inside
Wind turbines –
Part 26-2: Production-based availability for wind turbines
IEC TS 61400-26-2:2014-06(en)
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IEC TS 61400-26-2
®
Edition 1.0 2014-06
TECHNICAL
SPECIFICATION
colour
inside
Wind turbines –
Part 26-2: Production-based availability for wind turbines
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
X
ICS 27.180 ISBN 978-2-8322-1618-7
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC TS 61400-26-2:2014 © IEC 2014
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviations . 8
3.1 Terms and definitions . 8
3.2 Abbreviations . 9
3.2.1 Information available . 9
3.2.2 Information unavailable . 11
4 Information model . 12
4.1 General . 12
4.2 Allocation of production terms to the information categories . 14
4.3 Mean-value based information . 15
4.4 Limitations . 15
4.5 Entry and exit points . 15
4.6 Information category priority . 16
Annex A (informative) Possible methods for the determination of potential energy
production . 17
A.1 General . 17
A.2 Specific power curve and velocities methods . 17
A.2.1 General . 17
A.2.2 Nacelle anemometer wind measurement with power curve . 17
A.2.3 Upstream wind measurement with power curve . 18
A.2.4 Met mast wind measurement with correction factors and power curve . 18
A.3 Power-based methods . 19
A.3.1 General . 19
A.3.2 Average production of wind farm. 19
A.3.3 Average production of representative comparison turbines . 20
A.3.4 Data acquisition with comparison chart/database . 21
A.3.5 Average wind speed of wind farm . 21
Annex B (informative) Production-based availability indicators – examples . 23
B.1 General . 23
B.2 System operational production-based availability (“WTGS user’s view”) . 23
B.2.1 General . 23
B.2.2 System operational production-based availability algorithm based on
mandatory information categories only . 23
B.2.3 Turbine operational production-based availability algorithm – including
optional information categories . 24
B.3 Technical production-based availability (“WTGS manufacturer’s view”) . 25
B.3.1 General . 25
B.3.2 Technical production-based availability based on mandatory information
categories only . 25
Annex C (informative) Capacity factor and other performance indicators . 27
C.1 General . 27
C.2 Capacity factor . 27
C.3 Production ratio . 28
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IEC TS 61400-26-2:2014 © IEC 2014 – 3 –
Annex D (informative) Verification scenarios – examples . 29
D.1 General . 29
D.2 Application scenarios . 29
D.2.1 General . 29
D.2.2 Scenarios under FULL PERFORMANCE . 29
D.2.3 Scenarios under PARTIAL PERFORMANCE . 31
D.2.4 Scenarios under TECHNICAL STANDBY . 34
D.2.5 Scenarios under OUT OF ENVIRONMENTAL SPECIFICATION . 34
D.2.6 Scenarios under REQUESTED SHUTDOWN . 35
D.2.7 Scenarios under OUT OF ELECTRICAL SPECIFICATION . 37
D.2.8 Scenarios under SCHEDULED MAINTENANCE . 37
D.2.9 Scenarios under PLANNED CORRECTIVE ACTION . 38
D.2.10 Scenarios under FORCED OUTAGE . 38
D.2.11 Scenarios under SUSPENDED . 40
D.2.12 Scenarios under FORCE MAJEURE . 40
D.3 Calculation of production-based availability indicators according to Annex B . 41
D.3.1 General . 41
D.3.2 System operational production-based availability algorithm based on
mandatory information categories only (“WTGS user’s view”) . 41
D.3.3 Turbine operational production-based availability algorithm – including
optional categories (“WTGS user’s view”) . 42
D.3.4 Technical production-based availability based on mandatory information
categories only (“WTGS manufacturer's view”) . 44
Annex E (informative) Considerations of competing assignment of lost production . 46
Bibliography . 47
Figure 1 – Information category overview . 12
Figure 2 – Extended information category model. 13
Figure 3 – Information categories, addition of layer 2 and layer 3, mandatory
categories . 14
Figure A.1 – Step 1: Calculation of wind speed based on working wind turbine 1 to n . 22
Figure A.2 – Step 2: Estimation of lost production for WTGS not in FULL
PERFORMANCE . 22
Figure E.1 – Example of simultaneous degrading and derating . 46
Table D.1 – FULL PERFORMANCE: By definition, actual energy production is equal to
the potential energy production . 29
Table D.2 – FULL PERFORMANCE: Actual energy production is less than potential
energy production . 30
Table D.3 – FULL PERFORMANCE: Actual energy production greater than potential
energy production . 31
Table D.4 – Partial performance – Derated: Grid constraint . 31
Table D.5 – Partial performance – Derated: Grid constraint, actual energy production
less than potential energy production . 32
Table D.6 – Partial performance – Derated: Output constraint due to excessive noise
from the WTGS . 32
Table D.7 – Partial performance – Derated: Dirt on blades constrained performance . 33
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Table D.8 – Partial performance – Derated: Ice accumulated on blades has been
detected and the WTGS is allowed to operate although the power performance is
derated . 33
Table D.9 – Partial performance – Degraded: WTGS deterioration known to the WTGS
user . 34
Table D.10 – TECHNICAL STANDBY: WTGS is cable unwinding . 34
Table D.11 – Out of environmental specification: Calm winds . 34
Table D.12 – Out of environmental specification: High winds . 35
Table D.13 – Out of environmental specification: Temperature too high . 35
Table D.14 – REQUESTED SHUTDOWN: Ice on blades is detected and WTGS user
requests shutdown of the WTGS . 35
Table D.15 – Requested shutdown: Sector management . 36
Table D.16 – Requested shutdown: Noise nuisance . 36
Table D.17 – Out of electrical specification: Low voltage . 37
Table D.18 – SCHEDULED MAINTENANCE: WTGS is under scheduled maintenance
work by the WTGS manufacturer within the time allowance agreed by the maintenance
contract . 37
Table D.19 – PLANNED CORRECTIVE ACTION: WTGS manufacturer performs
corrective action to the WTGS at his discretion outside the time allowance of
scheduled maintenance . 38
Table D.20 – Forced outage: Short circuit . 38
Table D.21 – Forced outage: Corrosion. 39
Table D.22 – Forced outage: Overheating . 39
Table D.23 – SUSPENDED: Suspended repair work due to storm with lightning . 40
Table D.24 – FORCE MAJEURE: no access to the WTGS due to flooding impacting
infrastructure . 40
Table D.25 – System operational production-based availability algorithm based on
mandatory information categories only (“WTGS user’s view”) . 41
Table D.26 – Turbine operational production-based availability algorithm – including
optional categories (“WTGS user’s view”) . 43
Table D.27 – Technical production-based availability based on mandatory information
categories only (“WTGS manufacturer's view”) . 44
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IEC TS 61400-26-2:2014 © IEC 2014 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND TURBINES –
Part 26-2: Production-based availability for wind turbines
FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
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 TS 61400-26-2, which is a technical specification, has been prepared by IEC technical
committee 88: Wind turbines.
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The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
88/455/DTS 88/483/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61400 series, under the general title Wind turbines, can be found
on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual edition of this document may be issued at a later date.
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IEC TS 61400-26-2:2014 © IEC 2014 – 7 –
INTRODUCTION
The intention of this technical specification is to define a common basis for exchange of
information on performance indicators between owners, utilities, lenders, operators,
manufacturers, consultants, regulatory bodies, certification bodies, insurance companies and
other stakeholders in the wind power generation business. This is achieved by providing an
information model specifying how time designations shall be split into information categories.
The information model forms the basis for how to allocate time for reporting availability and
reliability indicators.
The technical specification defines generic terms of wind turbine systems and environmental
constraints in describing system and component availability, lifetime expectancy, repairs and
criteria for determining overhaul intervals. The specification defines terminology and generic
terms for reporting energy based generating unit availability measurement. A generating unit
includes all equipment up to the point of electrical connection. Availability measurements are
concerned with fractions of time and energy a unit is capable of providing during service,
taking environmental aspects into account. Environmental aspects will be wind and other
weather conditions, as well as grid and substation conditions. The specification furthermore
defines terminology and terms for reporting performance indicators based on energy
production. Mandatory information categories defined in the technical specification are written
in capital letters; optional information categories defined in the technical specification are
written in bold letters.
The project scope is accomplished by separating the technical specification into three parts:
• IEC TS 61400-26-1, which specifies terms for time-based availability of a wind turbine
generating system;
• IEC TS 61400-26-2, which specifies terms for production-based availability of a wind
turbine generating system;
• IEC/TS 61400-26-3, which specifies terms for time-based and production-based
availability of a wind power station.
Part 2 is an extension of Part 1 that deals with the use of production elements based on the
information model defined in Part 1. The structure and interrelations in the applied information
model are defined in Part 1 and apply to the production based extensions made in Part 2.
The intention of Part 2 is to define a common basis for exchange of information on production-
based availability. This is achieved by using the information model specifying how time and
energy designations shall be split into information categories and assigned to production
terms.
NOTE The point of electrical connection is defined individually from one project to the other, but is normally
understood as the electrical low voltage or high voltage terminals of the wind turbine generating system connecting
to the feeder cables.
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WIND TURBINES –
Part 26-2: Production-based availability for wind turbines
1 Scope
This part of IEC 61400 provides a framework from which production-based performance
indicators of a WTGS (wind turbine generator system) can be derived. It unambiguously
describes how data is categorised and provides examples of how the data can be used to
derive performance indicators.
The approach of this part of IEC 61400 is to expand the time allocation model, introduced in
IEC TS 61400-26-1, with two additional layers for recording of the actual energy production
and potential energy production associated with the concurrent time allocation.
It is not the intention of this Technical Specification to define how production-based
availability shall be calculated. Nor is it the intention to form the basis for power curve
performance measurements, which is the objective of IEC 61400-12.
This document also includes informative annexes with:
• examples of determination of lost production,
• examples of algorithms for production-based indicators,
• examples of other performance indicators,
• examples of application scenarios.
2 Normative references
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.
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at
IEC TS 61400-26-1:2011, Wind turbines – Part 26-1: Time-based availability for wind turbine
generating systems
3 Terms, definitions and abbreviations
For the purposes of the present document, the following terms, definitions and abbreviations
apply, as well as the relevant terms and definitions contained in IEC TS 61400-26-1 and
IEC 60050-415.
3.1 Terms and definitions
3.1.1
site conditions
conditions affecting the energy production of the WTGS, e.g. topographic, climatic and
meteorological conditions, sector management, electrical environment and contractual
constraints
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IEC TS 61400-26-2:2014 © IEC 2014 – 9 –
3.1.2
actual energy production
energy measured at the point of connection to the power collection system (according to IEV
and IEC 60050-415)
Note 1 to entry: The connection point may be at low voltage level or at medium or high voltage level depending on
the design of the WTGS.
3.1.3
potential energy production
calculated energy based on the WTGS design criteria and technical specifications and the site
conditions
3.1.4
lost production
energy not supplied
Note 1 to entry: The lost production is the difference between potential energy production potential energy
production and actual energy production.
3.2 Abbreviations
3.2.1 Information available
IA Information available category
IAO Information available operative category
IAOG Information available operative generating category
IAOGFP Information available operative generating with full performance category
IAOGPP Information available operative generating with partial performance category
IAONG Information available operative non generating category
IAONGTS Information available operative non generating technical standby category
IAONGEN Information available operative non generating out of environmental
specification category
IAONGEL Information available operative non generating out of electrical specification
category
IAONGRS Information available operative non generating requested shutdown
category
IANO Information available non operative category
IANOSM Information available non operative scheduled maintenance category
IANO
...
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