IEC TS 61400-26-2:2014

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.

General Information

• Status: Replaced
• Publication Date: 03-Jun-2014
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Drafting Committee: WG 26 - TC 88/WG 26
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 29-May-2019

Relations

• Replaced By: IEC 61400-26-1:2019 - Wind energy generation systems - Part 26-1: Availability for wind energy generation systems
• Effective Date: 05-Sep-2023

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

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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

– 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

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

– 4 – IEC TS 61400-26-2:2014 © IEC 2014

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

Ta
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