IEC TR 61000-3-7:2008

Electromagnetic compatibility (EMC) - Part 3-7: Limits - Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems

This part of IEC 61000 provides guidance on principles which can be used as the basis for determining the requirements for the connection of fluctuating installations to MV, HV and EHV public power systems (LV installations are covered in other IEC documents). For the purposes of this report, a fluctuating installation means an installation (which may be a load or a generator) that produces voltage flicker and / or rapid voltage changes. The primary objective is to provide guidance to system operators or owners on engineering practices which will facilitate the provision of adequate service quality for all connected customers. In addressing installations, this document is not intended to replace equipment standards for emission limits. This report addresses the allocation of the capacity of the system to absorb disturbances. It does not address how to mitigate disturbances, nor does it address how the capacity of the system can be increased. Since the guidelines outlined in this report are necessarily based on certain simplifying assumptions, there is no guarantee that this approach will always provide the optimum solution for all flicker situations. The recommended approach should be used with flexibility and engineering judgment as far as engineering is concerned, when applying the given assessment procedures in full or in part. The system operator or owner is responsible for specifying requirements for the connection of fluctuating installations to the system. The fluctuating installation is to be understood as the customer's complete installation (i.e. including fluctuating and non fluctuating parts). Problems related to voltage fluctuations fall into two basic categories:
- Flicker effect from light sources as a result of voltage fluctuations;
- Rapid voltage changes even within the normal operational voltage tolerances are considered as a disturbing phenomenon.
The report gives guidance for the coordination of the flicker emissions between different voltage levels in order to meet the compatibility levels at the point of utilisation. This report primarily focuses on controlling or limiting flicker, but a clause is included to address the limitation of rapid voltage changes. This second edition cancels and replaces the first edition published in 1996 and constitutes a technical revision. This new edition is significantly more streamlined than the original technical report (Edition 1), and reflects the experiences gained in the application of the first edition. This technical report has also been harmonised with IEC/TR 61000-3-6 and IEC/TR 61000-3-13. This Technical Report has the status of a basic EMC publication in accordance with IEC Guide 107.

General Information

• Status: Published
• Publication Date: 21-Feb-2008
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.100.10 - Emission
• Technical Committee: SC 77A - EMC - Low frequency phenomena
• Drafting Committee: WG 8 - TC 77/SC 77A/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 15-May-2008
• Completion Date: 22-Feb-2008

Relations

• Revises: IEC TR 61000-3-7:1996 - Electromagnetic compatibility (EMC) - Part 3: Limits - Section 7: Assessment of emission limits for fluctuating loads in MV and HV power systems - Basic EMC publication
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC/TR 61000-3-7
Edition 2.0 2008-02
TECHNICAL
REPORT
BASIC EMC PUBLICATION
Electromagnetic compatibility (EMC) –
Part 3-7: Limits – Assessment of emission limits for the connection of
fluctuating installations to MV, HV and EHV power systems

IEC/TR 61000-3-7:2008(E)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC/TR 61000-3-7
Edition 2.0 2008-02
TECHNICAL
REPORT
BASIC EMC PUBLICATION
Electromagnetic compatibility (EMC) –
Part 3-7: Limits – Assessment of emission limits for the connection of
fluctuating installations to MV, HV and EHV power systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XB
CODE PRIX
ICS 33.100.10 ISBN 2-8318-9606-1

– 2 – TR 61000-3-7 © IEC:2008(E)
CONTENTS
FOREWORD.5
INTRODUCTION.7
ACKNOWLEDGMENT.8

1 Scope.9
2 Normative references .10
3 Terms and definitions .10
4 Basic EMC concepts related to voltage fluctuations.13
4.1 Compatibility levels .14
4.2 Planning levels.14
4.2.1 Indicative values of planning levels.14
4.2.2 Assessment procedure for evaluation against planning levels.15
4.3 Illustration of EMC concepts.16
4.4 Emission levels .17
5 General principles .18
5.1 Stage 1: simplified evaluation of disturbance emission .18
5.2 Stage 2: emission limits relative to actual system characteristics.18
5.3 Stage 3: acceptance of higher emission levels on a conditional basis.19
5.4 Responsibilities .19
6 General guidelines for the assessment of emission levels .19
6.1 Point of evaluation.19
6.2 Definition of flicker emission level .20
6.3 Assessment of flicker emission levels.20
6.4 Declared system short circuit power or impedance .21
6.4.1 Short-circuit power or impedance for pre-connection assessment of
emission levels.21
6.4.2 Short-circuit power or impedance for assessing actual emission
levels.21
6.5 General guidelines for assessing the declared system impedance.21
7 General summation law .21
8 Emission limits for fluctuating installations connected to MV systems .22
8.1 Stage 1: simplified evaluation of disturbance emission .22
8.2 Stage 2: emission limits relative to actual system characteristics.23
8.2.1 Global emission to be shared between the customers.23
8.2.2 Individual emission limits .24
8.3 Stage 3: acceptance of higher emission levels on a conditional basis.25
8.4 Summary diagram of the evaluation procedure .26
9 Emission limits for fluctuating installations connected to HV or EHV systems .28
9.1 Stage 1: simplified evaluation of disturbance emission .28
9.2 Stage 2: emission limits relative to actual system characteristics.28
9.2.1 Assessment of the total available power .28
9.2.2 Individual emission limits .29
9.3 Stage 3: acceptance of higher emission levels on a conditional basis.30
10 Rapid voltage changes .31
10.1 General considerations.31
10.2 Compatibility level .32

TR 61000-3-7 © IEC:2008(E) – 3 –
10.3 Planning levels.32
10.4 Emission limits .33
10.5 Assessment procedure for evaluation against planning levels & emission
limits .33

Annex A (informative) P = 1 curves and numerical data for 230 V and 120 V

st
applications .34
Annex B (informative) Guidelines on the assessment of flicker transfer coefficient.36
Annex C (informative) Example of reallocation of global contributions and planning
levels considering transfer coefficients.37
Annex D (informative) The use of the severity indicators A and A to simplify
st lt
calculations.39
Annex E (informative) Pre-connection and post-connection assessment of emission for
P .40
st
Annex F (informative) Addition of P from different busbars.49
st
Annex G (informative) Examples of case studies .51
Annex H (informative) List of symbols and subscripts .62

Bibliography.64

Figure 1 – Illustration of basic voltage quality concepts with time/ location statistics
covering the whole system.17
Figure 2 – Illustration of basic voltage quality concepts with time statistics relevant to
one site within the whole system.
Figure 3 – Example of a system for sharing global contributions at MV .23
Figure 4 – Diagram of evaluation procedure.27
Figure 5 – Determination of S for a simple HV or EHV system.28
t
Figure 6 – Determination of S for a meshed HV or EHV system .29
t
Figure 7 – Equivalent circuit and vector diagram for simple assessments .31
Figure 8 – Example rapid voltage change associated with motor starting .31
Figure 9 – Example rapid voltage change associated with capacitor switching .32
Figure A.1 – P = 1 curve for regular rectangular voltage changes [13].34
st
Figure E.1 – Shape factor curve for pulse and ramp changes .41
Figure E.2 – Shape factor curves for double-step and double-ramp changes .42
Figure E.3 – Shape factor curves for sinusoidal and triangular changes.42
Figure E.4 – Shape factor curves for aperiodic changes .43
Figure E.5 – Accounting for network loading .45
Figure E.6 – System for flicker emission assessment.47
Figure E.7 – Assessment of emission level using current measurements .48
Figure F.1 – Example of two loads fed from different busbars .49
Figure G.1 – Example of effect from a rolling mill.51
Figure G.2 – Example of effect of multiple spot welder load .53
Figure G.3 – Example profile of winder reactive power levels.57
Figure G.4 – Normal system configuration .
...