IEC 61400-12-0:1998

Wind turbine generator systems - Part 12: Wind turbine power performance testing

Specifies a procedure for measuring the power performance characteristics of a single wind turbine generator system (WTGS) and applies to the testing of WTGS of all types and sizes connected to the electrical network.

General Information

• Status: Replaced
• Publication Date: 25-Feb-1998
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 88 - Wind energy generation systems
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 16-Dec-2005

Relations

• Replaced By: IEC 61400-12-1:2005 - Wind turbines - Part 12-1: Power performance measurements of electricity producing wind turbines
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
61400-12
First edition
1998-02
Wind turbine generator systems –
Part 12:
Wind turbine power performance testing
Aérogénérateurs –
Partie 12:
Techniques de mesure des performances de puissance

Reference number
IEC 61400-12:1998(E)
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series.

Consolidated publications
Consolidated versions of some IEC publications including amendments are available. For example, edition numbers
1.0, 1.1 and 1.2 refer, respectively, to the base publication, the base publication incorporating amendment 1 and the

base publication incorporating amendments 1 and 2.

Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC, thus ensuring that the content
reflects current technology.
Information relating to the date of the reconfirmation of the publication is available in the IEC catalogue.
Information on the revision work, the issue of revised editions and amendments may be obtained from IEC National
Committees and from the following IEC sources:
• IEC Bulletin
• IEC Yearbook
On-line access*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line access)*
Terminology, graphical and letter
symbols
For general terminology, readers are referred to IEC 60050: International Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for general use, readers are referred to
publications IEC 60027: Letter symbols to be used in electrical technology, IEC 60417: Graphical symbols for use on
equipment. Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols for diagrams.
IEC publications prepared by the same
technical committee
The attention of readers is drawn to the end pages of this publication which list the IEC publications issued by the
technical committee which has prepared the present publication.
* See web site address on title page.

INTERNATIONAL IEC
STANDARD
61400-12
First edition
1998-02
Wind turbine generator systems –
Part 12:
Wind turbine power performance testing
Aérogénérateurs –
Partie 12:
Techniques de mesure des performances de puissance

 IEC 1998 Copyright - all rights reserved  Droits de reproduction réservés
No part of this publication may be reproduced or utilized in Aucune partie de cette publication ne peut être reproduite ni
any form or by any means, electronic or mechanical, utilisée sous quelque forme que ce soit et par aucun
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writing from the publisher. copie et les microfilms, sans l'accord écrit de l'éditeur.
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For price, see current catalogue

– 2 – 61400-12 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 4

INTRODUCTION . 5

Clause
1 General. 6

1.1 Scope. 6
1.2 Normative references. 6
1.3 Definitions . 7
1.4 Symbols and units. 9
1.5 Abbreviations. 10
2 Test conditions. 11
2.1 Wind turbine generator system. 11
2.2 Test site. 11
3 Test equipment. 13
3.1 Electric power. 13
3.2 Wind speed. 13
3.3 Wind direction. 14
3.4 Air density. 14
3.5 Precipitation. 14
3.6 Wind turbine generator system status . 14
3.7 Data acquisition system . 14
4 Measurement procedure. 15
4.1 Introduction. 15
4.2 Wind turbine generator system operation . 15
4.3 Data collection. 15
4.4 Data selection. 15

4.5 Data correction. 16
4.6 Database. 16
5 Derived results. 16
5.1 Data normalization. 16
5.2 Determination of measured power curve . 17
5.3 Annual energy production (AEP). 18
5.4 Power coefficient. 19
6 Reporting format. 19
Tables
1 Example of presentation of a measured power curve. 22
2 Example of presentation of estimated annual energy production. 23

61400-12  IEC:1998(E) – 3 –
Page
Figures
1 Requirements as to distance of the meteorological mast and maximum allowed

measurement sectors . 12

2 Presentation of example data: power performance test scatter plots. 20

3 Presentation of example measured power curve. 21

Annexes
A Assessment of test site. 24
B Calibration of test site . 28
C Evaluation of uncertainty in measurement . 29
D Theoretical basis for determining the uncertainty of measurement using the method
of bins . 31
E Bibliography. 44

– 4 – 61400-12 © IEC:1998(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
WIND TURBINE GENERATOR SYSTEMS –

Part 12: Wind turbine power performance testing

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61400-12 has been prepared by IEC technical committee 88: Wind
turbine generator systems.
The text of this standard is based on the following documents:
FDIS Report on voting
88/85/FDIS 88/89/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
A bilingual version of this standard may be issued at a later date.
Annexes A and C form an integral part of this standard.
Annexes B, D and E are for information only.

61400-12  IEC:1998(E) – 5 –
INTRODUCTION
The purpose of this part of IEC 61400 is to provide a uniform methodology that will ensure

consistency and accuracy in the measurement and analysis of power performance by wind

turbine generator systems (WTGS). The standard has been prepared with the anticipation that
it would be applied by:
– the WTGS manufacturer striving to meet well-defined power performance requirements

and/or a possible declaration system;

– the WTGS purchaser in specifying such performance requirements;

– the WTGS operator who may be required to verify that stated, or required, power
performance specifications are met for new or refurbished units;
– the WTGS planner or regulator who must be able to accurately and fairly define power
performance characteristics of WTGS in response to regulations or permit requirements for
new or modified installations.
This standard provides guidance in the measurement, analysis, and reporting of power
performance testing for wind turbine generator systems (WTGS). The standard will benefit
those parties involved in the manufacture, installation planning and permitting, operation,
utilization, and regulation of WTGS. The technically accurate measurement and analysis
techniques recommended in this document should be applied by all parties to ensure that
continuing development and operation of WTGS is carried out in an atmosphere of consistent
and accurate communication relative to environmental concerns. This standard presents
measurement and reporting procedures expected to provide accurate results that can be
replicated by others.
However, readers should be warned that the site calibration procedure is quite new. As yet
there is no substantial evidence that it can provide accurate results for all sites, especially sites
in complex terrain. Part of the procedure is based on applying uncertainty calculations on the
measurements. In complex terrain situations it is not adequate to state that results are
accurate since uncertainties might be 10 % to 15 % in standard deviation. A new measurement
standard, accounting for these problems, will be developed in future.

– 6 – 61400-12 © IEC:1998(E)
WIND TURBINE GENERATOR SYSTEMS –

Part 12: Wind turbine power performance testing

1 General
1.1 Scope
This part of IEC 61400 specifies a procedure for measuring the power performance
characteristics of a single wind turbine generator system (WTGS) and applies to the testing of
WTGS of all types and sizes connected to the electrical power network. It is applicable for the
determination of both the absolute power performance characteristics of a WTGS and of
differences between the power performance characteristics of various WTGS configurations.
The WTGS power performance characteristics are determined by the measured power curve
and the estimated annual energy production (AEP). The measured power curve is determined
by collecting simultaneous measurements of wind speed and power output at the test site for a
period that is long enough to establish a statistically significant database over a range of wind
speeds and under varying wind conditions. The AEP is calculated by applying the measured
power curv
...