IEC 61000-4-27:2000

NORME CEI
INTERNATIONALE IEC
61000-4-27
INTERNATIONAL
Première édition
STANDARD
First edition
2000-08
PUBLICATION FONDAMENTALE EN CEM
BASIC EMC PUBLICATION
Compatibilité électromagnétique (CEM) –
Partie 4-27:
Techniques d'essai et de mesure –
Essai d'immunité aux déséquilibres
Electromagnetic compatibility (EMC) –
Part 4-27:
Testing and measurement techniques –
Unbalance, immunity test
Numéro de référence
Reference number
CEI/IEC 61000-4-27:2000
Numéros des publications Numbering
Depuis le 1er janvier 1997, les publications de la CEI As from 1 January 1997 all IEC publications are
sont numérotées à partir de 60000. issued with a designation in the 60000 series.
Publications consolidées Consolidated publications
Les versions consolidées de certaines publications de Consolidated versions of some IEC publications
la CEI incorporant les amendements sont disponibles. including amendments are available. For example,
Par exemple, les numéros d’édition 1.0, 1.1 et 1.2 edition numbers 1.0, 1.1 and 1.2 refer, respectively, to
indiquent respectivement la publication de base, la the base publication, the base publication incor-
publication de base incorporant l’amendement 1, et la porating amendment 1 and the base publication
publication de base incorporant les amendements 1 incorporating amendments 1 and 2.
et 2.
Validité de la présente publication Validity of this publication
Le contenu technique des publications de la CEI est The technical content of IEC publications is kept
constamment revu par la CEI afin qu'il reflète l'état under constant review by the IEC, thus ensuring that
actuel de la technique. the content reflects current technology.
Des renseignements relatifs à la date de reconfir- Information relating to the date of the reconfirmation
mation de la publication sont disponibles dans le of the publication is available in the IEC catalogue.
Catalogue de la CEI.
Les renseignements relatifs à des questions à l’étude et Information on the subjects under consideration and
des travaux en cours entrepris par le comité technique work in progress undertaken by the technical
qui a établi cette publication, ainsi que la liste des committee which has prepared this publication, as well
publications établies, se trouvent dans les documents ci- as the list of publications issued, is to be found at the
dessous: following IEC sources:
• «Site web» de la CEI* • IEC web site*
• Catalogue des publications de la CEI • Catalogue of IEC publications
Publié annuellement et mis à jour Published yearly with regular updates
régulièrement (On-line catalogue)*
(Catalogue en ligne)*
• Bulletin de la CEI
• IEC Bulletin
Disponible à la fois au «site web» de la CEI*
Available both at the IEC web site* and
et comme périodique imprimé
as a printed periodical
Terminologie, symboles graphiques
Terminology, graphical and letter
et littéraux
symbols
En ce qui concerne la terminologie générale, le lecteur
For general terminology, readers are referred to
se reportera à la CEI 60050: Vocabulaire Electro-
IEC 60050: International Electrotechnical Vocabulary
technique International (VEI).
(IEV).
Pour les symboles graphiques, les symboles littéraux
For graphical symbols, and letter symbols and signs
et les signes d'usage général approuvés par la CEI, le
approved by the IEC for general use, readers are
lecteur consultera la CEI 60027: Symboles littéraux à
referred to publications IEC 60027: Letter symbols to
utiliser en électrotechnique, la CEI 60417: Symboles
be used in electrical technology, IEC 60417: Graphical
graphiques utilisables sur le matériel. Index, relevé et
symbols for use on equipment. Index, survey and
compilation des feuilles individuelles, et la CEI 60617:
compilation of the single sheets and IEC 60617:
Symboles graphiques pour schémas.
Graphical symbols for diagrams.
* Voir adresse «site web» sur la page de titre.
* See web site address on title page.

NORME CEI
INTERNATIONALE IEC
61000-4-27
INTERNATIONAL
Première édition
STANDARD
First edition
2000-08
PUBLICATION FONDAMENTALE EN CEM
BASIC EMC PUBLICATION
Compatibilité électromagnétique (CEM) –
Partie 4-27:
Techniques d'essai et de mesure –
Essai d'immunité aux déséquilibres
Electromagnetic compatibility (EMC) –
Part 4-27:
Testing and measurement techniques –
Unbalance, immunity test
 IEC 2000 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
S
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

– 2 – 61000-4-27 © CEI:2000
SOMMAIRE
Pages
AVANT-PROPOS . 4
INTRODUCTION .8
Articles
1 Domaine d’application et objet. 10
2 Références normatives. 10
3 Définitions. 12
4 Généralités .12
5 Niveaux d’essai. 14
6 Matériels d’essai . 14
6.1 Générateurs d’essai . 14
6.2 Vérification des caractéristiques des générateurs d’essai . 16
7 Installation d’essai. 16
8 Procédures d’essai. 18
8.1 Conditions de référence en laboratoire . 18
8.2 Exécution des essais . 18
9 Evaluation des résultats d'essai. 20
10 Rapport d'essai . 20
Annex A (informative) Sources, effets et mesure du déséquilibre . 28
Annex B (informative) Calcul du taux de déséquilibre . 34
Annex C (informative) Informations sur les niveaux d’essai . 36
Annex D (Informative) Classes d’environnement électromagnétique . 38
Bibliographie . 40
Figure 1 – Exemple de tension d'alimentation triphasée déséquilibrée (essai 3). 24
Figure 2 – Succession de trois combinaisons de déséquilibre dans l’essai
(les tensions U , U , U sont alternées) . 24
a b c
Figure 3 – Schéma de l’instrumentation d’essai au déséquilibre . 26
Figure A.1 – Vecteurs de tension déséquilibrée. 30
Figure A.2 – Composantes des vecteurs déséquilibrés de la figure A.1 . 30
Tableau 1 – Niveaux d’essai . 14
Tableau 2 – Caractéristiques du générateur. 16

61000-4-27 © IEC:2000 – 3 –
CONTENTS
Page
FOREWORD . 5
INTRODUCTION .9
Clause
1 Scope and object . 11
2 Normative references . 11
3 Definitions. 13
4 General. 13
5 Test levels . 15
6 Test equipment . 15
6.1 Test generators. 15
6.2 Verification of the characteristics of the test generators . 17
7 Test set-up. 17
8 Test procedures . 19
8.1 Laboratory reference conditions . 19
8.2 Execution of the test . 19
9 Evaluation of test results . 21
10 Test report . 21
Annex A (informative) Sources, effects and measurement of unbalance . 29
Annex B (informative) Calculation of the degree of unbalance . 35
Annex C (informative) Information on test levels . 37
Annex D (informative) Electromagnetic environment classes . 39
Bibliography . 41
Figure 1 – Example of unbalanced three-phase supply voltage (Test 3). 25
Figure 2 – Succession of three unbalance sequences of the test (the voltages U , U , U
a b c
rotate) . 25
Figure 3 – Schematic diagram of test instrumentation for unbalance . 27
Figure A.1 – Unbalanced voltage vectors . 31
Figure A.2 – Components of the unbalanced vectors in figure A.1 . 31
Table 1 – Test levels . 15
Table 2 – Characteristics of the generator. 17

– 4 – 61000-4-27 © CEI:2000
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
___________
COMPATIBILITÉ ÉLECTROMAGNÉTIQUE (CEM) –
Partie 4-27: Techniques d’essai et de mesure –
Essai d’immunité aux déséquilibres
AVANT-PROPOS
1) La CEI (Commission Electrotechnique Internationale) est une organisation mondiale de normalisation composée
de l’ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a pour objet de
favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de
l’électricité et de l’électronique. A cet effet, la CEI, entre autres activités, publie des Normes internationales.
Leur élaboration est confiée à des comités d’études, aux travaux desquels tout Comité national intéressé par le
sujet traité peut participer. Les organisations internationales, gouvernementales et non gouvernementales, en
liaison avec la CEI, participent également aux travaux. La CEI collabore étroitement avec l’Organisation
Internationale de Normalisation (ISO), selon des conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de la CEI concernant des questions techniques, représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux intéressés
sont représentés dans chaque comité d’études.
3) Les documents produits se présentent sous la forme de recommandations internationales; ils sont publiés
comme normes, spécifications techniques, rapports techniques ou guides et agréés comme tels par les Comités
nationaux.
4) Dans le but d'encourager l'unification internationale, les Comités nationaux de la CEI s’engagent à appliquer de
façon transparente, dans toute la mesure possible, les Normes internationales de la CEI dans leurs normes
nationales et régionales. Toute divergence entre la norme de la CEI et la norme nationale ou régionale
correspondante doit être indiquée en termes clairs dans cette dernière.
5) La CEI n'a fixé aucune procédure concernant le marquage comme indication d'approbation et sa responsabilité
n'est pas engagée quand un matériel est déclaré conforme à l'une de ses normes.
6) L’attention est attirée sur le fait que certains des éléments de la présente Norme internationale peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 61000-4-27 a été établie par le sous-comité 77A: Phénomènes
basse fréquence, du comité d’études 77 de la CEI: Compatibilité électromagnétique.
Elle constitue la partie 4-27 de la CEI 61000. Elle a le statut de publication fondamentale en
CEM conformément au Guide 107 de la CEI.
Le texte de la présente norme est issu des documents suivants:
FDIS Rapport de vote
77A/308/FDIS 77A/314/RVD
Le rapport de vote mentionné dans le tableau ci-dessus donne toute information sur le vote
ayant abouti à l’approbation de cette norme.
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 3.
Les annexes A, B, C et D sont données uniquement à titre d’information.

61000-4-27 © IEC:2000 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-27: Testing and measurement techniques –
Unbalance, immunity test
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 cooperation on all questions concerning standardisation 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
Standardization Organization (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 published in the form of
standards, technical specifications, 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 an 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 61000-4-27 has been prepared by subcommittee 77A: Low-
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
It forms part 4-27 of IEC 61000. It has the status of basic EMC publication in accordance with
IEC Guide 107.
The text of this standard is based on the following documents:
FDIS Report on voting
77A/308/FDIS 77A/314/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annexes A, B, C and D are for information only.

– 6 – 61000-4-27 © CEI:2000
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant 2002. A cette
date, la publication sera
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou
• amendée.
61000-4-27 © IEC:2000 – 7 –
The committee has decided that the contents of this publication will remain unchanged until
2002. At this date, the publication will be:
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 8 – 61000-4-27 © CEI:2000
INTRODUCTION
La CEI 61000 est publiée sous forme de plusieurs parties séparées, conformément à la
structure suivante:
Partie 1: Généralités
Considérations générales (introduction, principes fondamentaux)
Définitions, terminologie
Partie 2: Environnement
Description de l’environnement
Classification de l’environnement
Niveaux de compatibilité
Partie 3: Limites
Limites d’émission
Limites d’immunité (dans la mesure où elles ne relèvent pas de la responsabilité des
comités de produits)
Partie 4: Techniques d’essai et de mesure
Techniques de mesure
Techniques d’essai
Partie 5: Guide d’installation et d’atténuation
Guides d’installation
Méthodes et dispositifs d’atténuation
Partie 6: Normes génériques
Partie 9: Divers
Chaque partie est à son tour subdivisée en plusieurs parties, publiées soit comme Normes
internationales, soit comme spécifications techniques ou rapports techniques, dont certaines
ont déjà été publiées en tant que sections. D’autres seront publiées sous le numéro de la
partie, suivi d’un tiret et complété d’un second chiffre identifiant la subdivision (exemple:
61000-6-1).
61000-4-27 © IEC:2000 – 9 –
INTRODUCTION
This standard is part of IEC 61000 series, according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 6: Generic standards
Part 9: Miscellaneous
Each part is further subdivided into several parts, published either as International Standards
or as technical specifications or technical reports, some of which have already been published
as sections. Others will be published with the part number followed by a dash and completed
by a second number identifying the subdivision (example: 61000-6-1).

– 10 – 61000-4-27 © CEI:2000
COMPATIBILITÉ ELECTROMAGNÉTIQUE (CEM) –
Partie 4-27: Techniques d’essai et de mesure –
Essai d’immunité aux déséquilibres
1 Domaine d’application et objet
La présente partie de la CEI 61000 est une publication fondamentale en CEM (Compatibilité
électromagnétique). Elle porte sur les essais d'immunité des équipements électriques et/ou
électroniques (appareils et systèmes) dans leur environnement électromagnétique. Seuls les
phénomènes conduits sont pris en compte, et notamment les essais d'immunité des
équipements reliés aux réseaux publics et industriels.
La présente norme a pour objet d'établir une référence pour évaluer l'immunité des
équipements électriques et électroniques soumis à des déséquilibres de tension.
Cette norme s'applique aux équipements triphasés électriques et/ou électroniques 50 Hz/
60 Hz, absorbant un courant nominal inférieur ou égal à 16 A par phase.
Cette norme ne s'applique pas aux équipements triphasés ayant un neutre s'ils fonctionnent
comme un groupe de charges monophasées branchées entre phase et neutre.
Cette norme ne s'applique pas aux équipements électriques et/ou électroniques raccordés aux
réseaux de distribution en courant alternatif à 400 Hz.
Les essais de cette norme ne comprennent pas les essais relatifs au facteur de déséquilibre
homopolaire.
Les niveaux d'immunité exigés pour un environnement électromagnétique particulier, ainsi que
les critères de performances, sont indiqués dans les normes de produit, de famille de produits
ou dans les normes génériques selon le cas. Cet essai d’immunité ne devrait être inclus dans
les normes de produit, de famille de produits ou dans des normes génériques que si le matériel
est susceptible de présenter une aptitude à la fonction ou un fonctionnement réduit lorsqu’il est
soumis à une alimentation en tension comportant un déséquilibre.
La vérification de la fiabilité des matériels électriques (condensateurs, moteurs, etc.) et les
effets de longue durée (plus de quelques minutes) ne sont pas traités dans cette norme.
2 Références normatives
Les documents normatifs suivants contiennent des dispositions qui, par suite de la référence
qui y est faite, constituent des dispositions valables pour la présente partie de la CEI 61000.
Pour les références datées, les amendements ultérieurs ou les révisions de ces publications
ne s’appliquent pas. Toutefois, les parties prenantes aux accords fondés sur la présente partie
de la CEI 61000 sont invitées à rechercher la possibilité d’appliquer les éditions les plus
récentes des normes indiquées ci-après. Pour les références non datées, la dernière édition du
document normatif en référence s’applique. Les membres de la CEI et de l’ISO possèdent le
registre des Normes internationales en vigueur.
CEI 60050(161), Vocabulaire électrotechnique international (VEI) – Chapitre 161: Compatibilité
électromagnétique
61000-4-27 © IEC:2000 – 11 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-27: Testing and measurement techniques –
Unbalance, immunity test
1 Scope and object
This part of IEC 61000 is a basic EMC (electromagnetic compatibility) publication. It considers
immunity tests for electric and/or electronic equipment (apparatus and system) in its electro-
magnetic environment. Only conducted phenomena are considered, including immunity tests
for equipment connected to public and industrial networks.
The object of this standard is to establish a reference for evaluating the immunity of electrical
and electronic equipment when subjected to unbalanced power supply voltage.
This standard applies to 50 Hz/60 Hz three-phase powered electrical and/or electronic
equipment with rated line current up to 16 A per phase.
This standard does not apply to equipment with three-phase plus neutral connection if that
equipment operates as a group of single-phase loads connected between phase and neutral.
This standard does not apply to electrical and/or electronic equipment connected to a.c. 400 Hz
distribution networks.
This standard does not include tests for the zero-sequence unbalance factor.
The immunity test levels required for a specific electromagnetic environment together with
performance criteria are indicated in the product, product family or generic standards as
applicable. This immunity test should be included in product, product family or generic
standards when equipment is likely to show reduced performance or function when exposed to
a supply voltage with voltage unbalance.
The verification of the reliability of electrical components (capacitors, motors, etc.) and long-
term effects (greater than a few minutes) is not considered in this standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61000. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 61000 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050(161), International Electrotechnical Vocabulary (IEV) – Chapter 161: Electro-
magnetic compatibility
– 12 – 61000-4-27 © CEI:2000
CEI 61000-2-4, Compatibilité électromagnétique (CEM) – Partie 2: Environnement – Section 4:
Niveaux de compatibilité dans les installations industrielles pour les perturbations conduites à
basse fréquence
3 Définitions
Pour les besoins de la présente partie de la CEI 61000, les définitions suivantes s’appliquent.
3.1
immunité (à une perturbation)
aptitude d’un dispositif, d'un appareil ou d’un système à fonctionner sans dégradation en
présence d’une perturbation électromagnétique
[VEI 161-01-20]
3.2
déséquilibre de tension
dans un réseau d’énergie électrique polyphasé, état dans lequel les valeurs efficaces des
tensions entre conducteurs ou les différences de phase entre conducteurs ne sont pas toutes
égales
[VEI 161-08-09]
3.3
taux de déséquilibre k (%)
u2
rapport entre la composante inverse et la composante directe, mesurées à la fréquence du
réseau (50 Hz ou 60 Hz) telles qu’elles sont définies dans le système des composantes
symétriques
k = 100 % (U / U ) (tension inverse / tension directe)

u2 2 1
NOTE Dans un réseau, les tensions inverses résultent principalement des courants inverses des charges
déséquilibrées circulant sur le réseau.
3.4
dysfonctionnement
impossibilité, pour l'équipement, de continuer à assurer les fonctions prévues, ou exécution par
l'équipement de fonctions non prévues
4 Généralités
Les équipements électriques et électroniques triphasés peuvent être affectés par des
déséquilibres de tension. L'annexe A décrit les sources, les effets et la procédure de mesure
de cette perturbation.
Les déséquilibres ont pour origine des variations d'amplitude ou des déphasages de la tension.
L'annexe B donne une formule pour calculer le taux de déséquilibre reposant sur ces
paramètres.
Le but de l’essai est d'étudier l'influence du déséquilibre de l’alimentation triphasée sur les
équipements pouvant y être sensibles, et risquant de provoquer:
– des surintensités dans les machines tournantes à courant alternatif;
– l'apparition d'harmoniques non caractéristiques dans les convertisseurs de puissance;
– des problèmes de synchronisation ou des dysfonctionnements dans le contrôle-commande
des équipements électriques (voir annexe A).

61000-4-27 © IEC:2000 – 13 –
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2: Environment – Section 4:
Compatibility levels in industrial plants for low-frequency conducted disturbances
3 Definitions
For the purposes of this part of IEC 61000, the following definitions apply.
3.1
immunity (to a disturbance)
ability of a device, equipment or system to perform without degradation in the presence of an
electromagnetic disturbance
[IEV 161-01-20]
3.2
voltage unbalance
in a polyphase system, condition in which the r.m.s. values of the phase voltages or the phase
angles between consecutive phases are not all equal
[IEV 161-08-09]
3.3
unbalance factor k (%)
u2
ratio of the negative sequence component to the positive sequence component measured at
mains frequency (50 Hz or 60 Hz) as defined by the method of symmetrical components
k = 100 % (U / U ) (negative-sequence voltage/positive-sequence voltage)
u2 2 1
NOTE The negative-sequence voltages in a network mainly result from the negative currents of unbalanced loads
flowing in the network.
3.4
malfunction
termination of the ability of an equipment to carry out intended functions or the execution of
unintended functions by the equipment
4 General
Three-phase electrical and electronic equipment may be affected by voltage unbalance.
Annex A describes the sources, effects and measurement of this disturbance.
Unbalance is caused by either voltage amplitude or phase-shift variations. A formula for the
calculation of the unbalance factor, based upon these parameters, is given in annex B.
The purpose of the test is to investigate the influence of unbalance in a three-phase voltage
system on equipment which may be sensitive to this disturbance, which could cause:
− overcurrents in a.c. rotating machines;
− generation of non-characteristic harmonics in electronic power converters;
− synchronization problems or control errors in the control part of electrical equipment (see
annex A).
– 14 – 61000-4-27 © CEI:2000
5 Niveaux d’essai
L'équipement à l’essai (EST) est placé en régime permanent à la tension nominale du réseau,
puis soumis à une séquence de déséquilibre telle qu’elle est décrite à la figure 2.
Le tableau 1 spécifie les niveaux d’essai qui ont été obtenus comme expliqué à l’annexe C.
La durée de l’essai de déséquilibre, spécifiée entre 0,1 s et 60 s, est considérée comme
adéquate pour observer les effets à court terme.
Tableau 1 – Niveaux d’essai
Numéro Niveau Niveau d’essai pour la classe 2 Niveau d’essai pour la classe 3 Niveau
d’essai d’essai d’essai
pour la
pour la
k k
Phase Ampli- Angle u2 Durée Phase Ampli- Angle u2 Durée
classe 1
classe
tude tude
° °
X
% s % s
% UN % UN
100 0° 100 0°
Ua Ua
Essai non
Essai 1 néces- U 95,2 125° 6 30 U 93,5 127° 8 60
b b
saire
U 90 240° U 87 240°
c c
U 100 0° U 100 0°
a a
Essai 2 U 90 131° 13 15 U 87 134° 17 15
b b
U 80 239° U 74 238°
c c
U 110 0° U 110 0°
a a
Essai 3 U 66 139° 25 0,1 U 66 139° 25 2
b b
U 71 235° U 71 235°
c c
NOTE 1 U est la tension nominale.
N
NOTE 2 U en retard par rapport à U et U en avance par rapport à U .
b a c a
Les essais sont respectivement spécifiés pour les niveaux 2 et 3 de la CEI 61000-2-4.
Les comités de produits peuvent spécifier leurs niveaux d’essais; cependant, pour les
matériels raccordés à un réseau public, il est recommandé que les niveaux ne soient pas
inférieurs à ceux spécifiés pour la classe 2.
6 Matériels d’essai
6.1 Générateurs d’essai
Le générateur doit être doté de dispositifs empêchant l'émission de perturbations qui, si elles
sont injectées dans le réseau d'alimentation, sont susceptibles d'influencer les résultats
d’essai.
La tension de sortie doit être ajustée à ±1% de U et la phase à ±0,3°.
N
61000-4-27 © IEC:2000 – 15 –
5 Test levels
The equipment under test (EUT) is set up at a steady mains voltage and is then subjected to
unbalance sequences according to figure 2.
Table 1 specifies the test levels which are derived as explained in annex C.
The duration of the unbalance test, specified between 0,1 s to 60 s, can be taken as a general
guide to study short-term effects.
Table 1 – Test levels
Test Test Test level for Class 2 Test level for Class 3 Test
number level level
Phase Ampli- Angle k Time Phase Ampli- Angle k Time
u2 u2
Class 1 for
tude tude
Class X
°
% U % s % U % s
N N
U 100 0° U 100 0°
a a
No test
Test 1 U 95,2 125° 6 30 U 93,5 127° 8 60
b b
required
U 90 240° U 87 240°
c c
U 100 0° U 100 0°
a a
Test 2 U 90 131° 13 15 U 87 134° 17 15
b b
U 80 239° U 74 238°
c c
U 110 0° U 110 0°
a a
Test 3 66 139° 25 0,1 66 139° 25 2
Ub Ub
U 71 235° U 71 235°
c c
NOTE 1 U is the nominal voltage
N
NOTE 2 U is lagging against U , and U is leading against U .
b a c a
Tests are respectively specified for equipment in relation to levels 2 and 3 in IEC 61000-2-4.
The product committee may specify any test level; however, for equipment connected to public
supply systems, it is recommended that the levels should not be lower than those defined for
class 2.
6 Test equipment
6.1 Test generators
The generator shall have provisions to prevent the emission of disturbances which, if injected
in the power supply network, may influence the test results.
The output voltage shall be adjusted to ±1% of U and the phase to ±0,3°.
N
– 16 – 61000-4-27 © CEI:2000
Tableau 2 – Caractéristiques du générateur
Caractéristique Spécification de performance
Tension de sortie U ± 50 %
N
Précision de la tension de sortie
±2 % de U
N
Intensité de sortie Suffisante pour alimenter l’EST dans toutes les
conditions d’essais
Dépassement ou diminution de la tension réelle, Moins de 5 % de la variation de tension
générateur chargé par une charge résistive de 100 Ω
Montée en tension (et temps de descente) pendant les
1 μs à 5 μs
variations de tension, générateur chargé par une charge
résistive de 100 Ω
Distorsion harmonique totale de la tension de sortie Moins de 3 %
Décalage de phase
0°, 120° et 240° ± 30°
Précision de phase
1° entre deux phases quelles qu’elles soient
Précision de fréquence 0,5 % de f (50 Hz ou 60 Hz)
6.2 Vérification des caractéristiques des générateurs d’essai
Compte tenu de la grande diversité des EST, des générateurs de différentes caractéristiques
de sortie peuvent être utilisés en fonction des besoins.
L'utilisateur doit vérifier que le générateur d’essai répond aux caractéristiques et spécifications
de performances indiquées dans le tableau 2, comme cela est requis par l’EST particulier.
Les performances du générateur d’essai peuvent être vérifiées avec une charge résistive égale
à la composante réelle de l'impédance de l’EST.
7 Installation d’essai
L’essai doit être effectué avec l’EST relié au générateur d’essai au moyen du câble
d’alimentation recommandé par le fabricant. Si la longueur du câble n'est pas spécifiée, elle
doit être la plus courte possible pour l’EST. Cette longueur doit être mentionnée dans le
rapport d’essai.
La figure 3 présente un schéma d’un générateur de tension déséquilibrée (modification
d'amplitude ou de phase) obtenue à l'aide d'un générateur avec amplificateur de puissance.
Les générateurs dotés de transformateurs et d’interrupteurs doivent avoir des transformateurs
variables sur au moins deux phases.
Les accès de l’EST doivent être raccordés aux périphériques appropriés, indiqués par le
fabricant. Si les périphériques appropriés ne sont pas disponibles, ils peuvent être simulés.

61000-4-27 © IEC:2000 – 17 –
Table 2 – Characteristics of the generator
Characteristic Performance specification
Output voltage capability
UN ± 50 %
Output voltage accuracy ±2 % of U .
N
Output current capability Sufficient to supply the EUT under all test conditions
Overshoot/undershoot of the actual voltage, generator Less than 5 % of the change in voltage
loaded with 100 Ω resistive load
Voltage rise (and fall time) during voltage changes, 1 μs to 5 μs
generator loaded with 100 Ω resistive load
Total harmonic distortion of the output voltage Less than 3 %
Phase shifting 0°, 120° and 240° ± 30°
Phase accuracy 1° between any two phases
Frequency accuracy
0,5 % of f1 (50 Hz or 60 Hz)
6.2 Verification of the characteristics of the test generators
It is recognized that there is a wide range of EUTs and that consequently test generators with
different output power capabilities may be used, as required.
The user shall verify that the test generator complies with the characteristics and performance
specifications listed in table 2, as required by the particular EUT.
The performance of the test generator may be verified with a resistive load equal to the real
component of the impedance of the EUT.
7 Test set-up
The test shall be performed with the EUT connected to the test generator with a supply cable
as specified by the manufacturer. If no cable length is specified, it shall be the shortest
possible length adapted to the EUT. The length shall be reported in the test report.
Figure 3 shows a schematic drawing for the generation of voltage unbalance (amplitude or
phase change) using a generator with power amplifier.
Generators with transformers and switches need to have variable transformers on at least two
phases.
The ports of the EUT shall be connected to appropriate peripherals as defined by the
manufacturer. If appropriate peripherals are not available, they may be simulated.

– 18 – 61000-4-27 © CEI:2000
8 Procédures d’essai
8.1 Conditions de référence en laboratoire
Afin de minimiser l’impact des paramètres liés à l’environnement sur les résultats des essais,
ceux-ci doivent être réalisés dans les conditions de référence climatiques et électromagné-
tiques indiquées en 8.1.1 et 8.1.2.
8.1.1 Conditions climatiques
A moins qu'il en soit spécifié autrement par le comité responsable d'une norme générique ou
d'une norme de produit, les conditions climatiques dans le laboratoire doivent être dans les
limites spécifiées pour le fonctionnement de l'EST et des matériels d'essai par les construc-
teurs respectifs.
Les essais ne doivent pas être réalisés si l'humidité relative est telle qu'elle cause une
condensation sur l'EST ou sur les matériels d'essai.
NOTE Lorsqu'il est estimé qu'il y a une évidence suffisante pour démontrer que les effets du phénomène couvert
par la présente norme sont influencés par les conditions climatiques, il convient d'en informer le comité
responsable de la présente norme.
8.1.2 Conditions électromagnétiques
Les conditions électromagnétiques du laboratoire ne doivent pas influencer les résultats des
essais.
8.2 Exécution des essais
L’EST doit être placé dans des conditions de fonctionnement normal.
Les essais doivent avoir lieu conformément à un programme d’essais qui doit indiquer:
– le numéro d’essai (voir tableau 1);
– le niveau d’essai;
– la durée de l’essai;
– les accès auxquels les essais doivent être appliqués;
– les conditions de fonctionnement représentatives de l’EST;
– les matériels auxiliaires.
L’alimentation, les signaux et les autres grandeurs électriques fonctionnelles doivent être
appliquées dans les limites de leurs plages assignées. Si les sources réelles des signaux
d’exploitation ne sont pas disponibles, elles peuvent être simulées.
Pour chaque niveau d’essai, une succession de trois combinaisons de déséquilibre au
minimum doit être appliquée, avec un intervalle de 3 min au moins entre deux combinaisons
consécutives (voir figure 2).
Les tensions d’essais appliquées doivent être obtenues par permutation circulaire comme
indiqué ci-après:
Première combinaison: U sur L ; U sur L ; U sur L ;
a 1 b 2 c 3
Seconde combinaison: U sur L ; U sur L ; U sur L ;
a 2 b 3 c 1
Troisième combinaison: U sur L ; U sur L ; U sur L .
a 3 b 1 c 2
61000-4-27 © IEC:2000 – 19 –
8 Test procedures
8.1 Laboratory reference conditions
In order to minimize the impact of environmental parameters on test results, the tests shall be
carried out in climatic and electromagnetic reference conditions as specified in 8.1.1 and 8.1.2.
8.1.1 Climatic conditions
Unless otherwise specified by the committee responsible for the generic or product standard,
the climatic conditions in the laboratory shall be within any limits specified for the operation of
the EUT and the test equipment by their respective manufacturers.
Tests shall not be performed if the relative humidity is so high as to cause condensation on the
EUT or the test equipment.
NOTE Where it is considered that there is sufficient evidence to demonstrate that the effects of the phenomenon
covered by this standard are influenced by climatic conditions, this should be brought to the attention of the
committee responsible for this standard.
8.1.2 Electromagnetic conditions
The electromagnetic conditions of the laboratory shall not influence the test results.
8.2 Execution of the test
The EUT shall be configured for its normal operating conditions.
The tests shall be performed according to a test plan that shall specify
− test number (see table 1);
− test level;
− test duration;
− ports to which the test shall be applied;
− representative operating conditions of the EUT;
− auxiliary equipment.
The power supply, signals and other functional electrical quantities shall be applied within their
rated range. If the actual operating signal sources are not available, they may be simulated.
For each test level, a succession of at least three unbalance sequences shall be applied, with
an interval of a least 3 min between each (see figure 2).
The applied test levels shall be rotated as follows:
First sequence:
U to L , U to L , U to L ;
a 1 b 2 c 3
Second sequence: U to L , U to L , U to L ;
a 2 b 3 c 1
Third sequence: U to L , U to L , U to L .
a 3 b 1 c 2
– 20 – 61000-4-27 © CEI:2000
où
U , U et U sont les tensions du générateur (voir tableau 1);
a b c
L , L et L sont les bornes d’alimentation de l’EST.
1 2 3
Les changements de tension d'alimentation doivent se produire aux passages à zéro de U . Le
a
générateur d’essai doit avoir en sortie une basse impédance en régime permanent et durant
les périodes de transition.
Toute dégradation des performances doit être relevée pour chaque essai. Il convient que le
matériel d'enregistrement soit capable d'afficher l'état du mode opératoire de l'appareil en
cours d’essai et après l’essai. Une vérification fonctionnelle complète doit être effectuée après
chaque groupe d’essai.
9 Evaluation des résultats d'essai
Les résultats d'essai doivent être classés en tenant compte de la perte de fonction ou de la
dégradation du fonctionnement du matériel soumis à l'essai, par rapport à un niveau de
comportement défini par son constructeur ou par le demandeur de l'essai, ou en accord entre
le constructeur et l'acheteur du produit. La classification recommandée est comme suit:
a) comportement normal dans les limites spécifiées par le constructeur, le demandeur de
l'essai ou l'acheteur;
b) perte temporaire de fonction ou dégradation temporaire du comportement cessant après la
disparition de la perturbation, le matériel soumis à l'essai retrouve alors son comportement
normal sans l'intervention d'un opérateur;
c) perte temporaire de fonction ou
...

IEC 61000-4-27 ®
Edition 1.1 2009-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC EMC PUBLICATION
PUBLICATION FONDAMENTALE EN CEM

Electromagnetic compatibility (EMC) –
Part 4-27: Testing and measurement techniques – Unbalance, immunity test for
equipment with input current not exceeding 16 A per phase

Compatibilité électromagnétique (CEM) –
Partie 4-27: Techniques d’essai et de mesure – Essai d’immunité aux
déséquilibres pour des matériels avec un courant appelé n’excédant pas 16 A
par phase
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IEC 61000-4-27 ®
Edition 1.1 2009-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC EMC PUBLICATION
PUBLICATION FONDAMENTALE EN CEM

Electromagnetic compatibility (EMC) –

Part 4-27: Testing and measurement techniques – Unbalance, immunity test for

equipment with input current not exceeding 16 A per phase

Compatibilité électromagnétique (CEM) –

Partie 4-27: Techniques d’essai et de mesure – Essai d’immunité aux

déséquilibres pour des matériels avec un courant appelé n’excédant pas 16 A

par phase
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.100.20 ISBN 978-2-8891-0388-1

– 2 – 61000-4-27 © IEC:2000+A1:2009
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope and object .6
2 Normative references.6
3 Definitions.7
4 General.7
5 Test levels.7
6 Test equipment.8
6.1 Test generators.8
6.2 Verification of the characteristics of the test generators.9
7 Test set-up.9
8 Test procedures.10
8.1 Laboratory reference conditions .10
8.2 Execution of the test .10
9 Evaluation of test results.11
10 Test report.11

Annex A (informative) Sources, effects and measurement of unbalance.14
Annex B (informative) Calculation of the degree of unbalance.17
Annex C (informative) Information on test levels .18
Annex D (informative) Electromagnetic environment classes .19

Bibliography .20

Figure 1 – Example of unbalanced three-phase supply voltage (Test 3) .12
Figure 2 – Succession of three unbalance sequences of the test (the voltages U , U , U
a b c
rotate).12
Figure 3 – Schematic diagram of test instrumentation for unbalance .13
Figure 4 – Example of test generator verification load.9
Figure A.1 – Unbalanced voltage vectors.15
Figure A.2 – Components of the unbalanced vectors in figure A.1.15

Table 1 – Test levels .8
Table 2 – Characteristics of the generator .8

61000-4-27 © IEC:2000+A1:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-27: Testing and measurement techniques –
Unbalance, immunity test for equipment with input current
not exceeding 16 A per phase
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of 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, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). 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. 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 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendment has been
prepared for user convenience.
IEC 61000-4-27 edition 1.1 contains first edition (2000) [documents 77A/308/FDIS and
77A/314/RVD] and its amendment 1 (2009) [documents 77A/672/FDIS and 77A/675/RVD].
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
International Standard IEC 61000-4-27 has been prepared by subcommittee 77A: Low-
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
It forms part 4-27 of IEC 61000. It has the status of basic EMC publication in accordance with
IEC Guide 107.
– 4 – 61000-4-27 © IEC:2000+A1:2009
Annexes A, B, C and D are for information only.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the maintenance result 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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61000-4-27 © IEC:2000+A1:2009 – 5 –
INTRODUCTION
This standard is part of IEC 61000 series, according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 6: Generic standards
Part 9: Miscellaneous
Each part is further subdivided into several parts, published either as International Standards
or as technical specifications or technical reports, some of which have already been published
as sections. Others will be published with the part number followed by a dash and completed
by a second number identifying the subdivision (example: 61000-6-1).

– 6 – 61000-4-27 © IEC:2000+A1:2009
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 4-27: Testing and measurement techniques –
Unbalance, immunity test for equipment with input current
not exceeding 16 A per phase
1 Scope and object
This part of IEC 61000 is a basic EMC (electromagnetic compatibility) publication. It considers
immunity tests for electric and/or electronic equipment (apparatus and system) in its electro-
magnetic environment. Only conducted phenomena are considered, including immunity tests
for equipment connected to public and industrial networks.
The object of this standard is to establish a reference for evaluating the immunity of electrical
and electronic equipment when subjected to unbalanced power supply voltage.
This standard applies to 50 Hz/60 Hz three-phase powered electrical and/or electronic
equipment with rated line current up to 16 A per phase.
This standard does not apply to equipment with three-phase plus neutral connection if that
equipment operates as a group of single-phase loads connected between phase and neutral.
This standard does not apply to electrical and/or electronic equipment connected to a.c. 400 Hz
distribution networks.
This standard does not include tests for the zero-sequence unbalance factor.
The immunity test levels required for a specific electromagnetic environment together with
performance criteria are indicated in the product, product family or generic standards as
applicable. This immunity test should be included in product, product family or generic
standards when equipment is likely to show reduced performance or function when exposed to
a supply voltage with voltage unbalance.
The verification of the reliability of electrical components (capacitors, motors, etc.) and long-
term effects (greater than a few minutes) is not considered in this standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61000. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 61000 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050(161), International Electrotechnical Vocabulary (IEV) – Chapter 161: Electro-
magnetic compatibility
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2: Environment – Section 4:
Compatibility levels in industrial plants for low-frequency conducted disturbances

61000-4-27 © IEC:2000+A1:2009 – 7 –
3 Definitions
For the purposes of this part of IEC 61000, the following definitions apply.
3.1
immunity (to a disturbance)
ability of a device, equipment or system to perform without degradation in the presence of an
electromagnetic disturbance
[IEV 161-01-20]
3.2
voltage unbalance
in a polyphase system, condition in which the r.m.s. values of the phase voltages or the phase
angles between consecutive phases are not all equal
[IEV 161-08-09]
3.3
unbalance factor k (%)
u2
ratio of the negative sequence component to the positive sequence component measured at
mains frequency (50 Hz or 60 Hz) as defined by the method of symmetrical components
k = 100 % (U / U ) (negative-sequence voltage/positive-sequence voltage)
u2 2 1
NOTE The negative-sequence voltages in a network mainly result from the negative currents of unbalanced loads
flowing in the network.
3.4
malfunction
termination of the ability of an equipment to carry out intended functions or the execution of
unintended functions by the equipment
4 General
Three-phase electrical and electronic equipment may be affected by voltage unbalance.
Annex A describes the sources, effects and measurement of this disturbance.
Unbalance is caused by either voltage amplitude or phase-shift variations. A formula for the
calculation of the unbalance factor, based upon these parameters, is given in annex B.
The purpose of the test is to investigate the influence of unbalance in a three-phase voltage
system on equipment which may be sensitive to this disturbance, which could cause:
− overcurrents in a.c. rotating machines;
− generation of non-characteristic harmonics in electronic power converters;
− synchronization problems or control errors in the control part of electrical equipment (see
annex A).
5 Test levels
The equipment under test (EUT) is set up at a steady mains voltage and is then subjected to
unbalance sequences according to figure 2.
Table 1 specifies the test levels which are derived as explained in annex C.
The duration of the unbalance test, specified between 0,1 s to 60 s, can be taken as a general
guide to study short-term effects.

– 8 – 61000-4-27 © IEC:2000+A1:2009
Table 1 – Test levels
Test Test Test level for Class 2 Test level for Class 3 Test
number level level
Phase Ampli- Angle k Time Phase Ampli- Angle k Time
u2 u2
Class 1 for
tude  tude
Class X
°
% U % s % U % s
N N
U 100 0°  U 100 0°
a a
No test
Test 1 U 95,2 125° 6 30 U 93,5 127° 8 60
b b
required
U 90 240°  U 87 240°
c c
U 100 0°  U 100 0°
a a
Test 2 U 90 131° 13 15 U 87 134° 17 15
b b
U 80 239°  U 74 238°
c c
U 110 0°  U 110 0°
a a
Test 3 U 66 139° 25 0,1 U 66 139° 25 2
b b
U 71 235°  U 71 235°
c c
NOTE 1 UN is the nominal voltage
NOTE 2 U is lagging against U , and U is leading against U .
b a c a
Tests are respectively specified for equipment in relation to levels 2 and 3 in IEC 61000-2-4.
The product committee may specify any test level; however, for equipment connected to public
supply systems, it is recommended that the levels should not be lower than those defined for
class 2.
6 Test equipment
6.1 Test generators
The generator shall have provisions to prevent the emission of disturbances which, if injected
in the power supply network, may influence the test results.
The output voltage shall be adjusted to ±1% of U and the phase to ±0,3°.
N
Table 2 – Characteristics of the generator
Characteristic Performance specification
Output voltage capability U +15, −40 %
N
Output voltage accuracy
±2 % of U .
N
Output current capability Sufficient to supply the EUT under all test conditions
Overshoot/undershoot of the actual voltage, generator Less than 5 % of the change in voltage
loaded with 100 Ω resistive load
Voltage rise (and fall time) during voltage changes,
1 μs to 5 μs
generator loaded with 100 Ω resistive load
Total harmonic distortion of the output voltage Less than 3 %
Phase shifting
0°, 120° and 240° ± 30°
Phase accuracy
1° between any two phases
Frequency accuracy 0,5 % of f (50 Hz or 60 Hz)
61000-4-27 © IEC:2000+A1:2009 – 9 –
6.2 Verification of the characteristics of the test generators
It is recognized that there is a wide range of EUTs and that consequently test generators with
different output power capabilities may be used, as required.
The test generator shall be verified that it complies with the characteristics and specifications
listed in Table 2. Performance of the test generator shall be verified with resistive loads
drawing an rms current of no more than the output capability of the generator.
In addition, the generator’s output current capability shall be verified as being able to provide a
crest factor of at least 3 when U is applied to a single phase load drawing an rms current of
N
no more than the output capability of the generator. Each output phase of the generator shall
be verified in turn. An example of a suitable 230V/16A verification load is given in Figure 4.

R
a
L
x
B
G
+
C R
N
IEC  228/09
Components
G Test generator
B Bridge rectifier
C 11 000 μF ± 20 % electrolytic capacitor
R 35 Ω ± 1 % resistor
R Additional resistor
a
NOTE R shall be selected so that the total series resistance (sum of the additional resistor R , the wiring
a a
resistance R , the internal resistance of two conducting diodes R , and the internal resistance of the
wire diodes
capacitor R ) is 92 mΩ (±10 %).
c
Figure 4 – Example of test generator verification load
7 Test set-up
The test shall be performed with the EUT connected to the test generator with a supply cable
as specified by the manufacturer. If no cable length is specified, it shall be the shortest
possible length adapted to the EUT. The length shall be reported in the test report.
Figure 3 shows a schematic drawing for the generation of voltage unbalance (amplitude or
phase change) using a generator with power amplifier.
Generators with transformers and switches need to have variable transformers on at least two
phases.
The ports of the EUT shall be connected to appropriate peripherals as defined by the
manufacturer. If appropriate peripherals are not available, they may be simulated.

– 10 – 61000-4-27 © IEC:2000+A1:2009
8 Test procedures
8.1 Laboratory reference conditions
In order to minimize the impact of environmental parameters on test results, the tests shall be
carried out in climatic and electromagnetic reference conditions as specified in 8.1.1 and 8.1.2.
8.1.1 Climatic conditions
Unless otherwise specified by the committee responsible for the generic or product standard,
the climatic conditions in the laboratory shall be within any limits specified for the operation of
the EUT and the test equipment by their respective manufacturers.
Tests shall not be performed if the relative humidity is so high as to cause condensation on the
EUT or the test equipment.
NOTE Where it is considered that there is sufficient evidence to demonstrate that the effects of the phenomenon
covered by this standard are influenced by climatic conditions, this should be brought to the attention of the
committee responsible for this standard.
8.1.2 Electromagnetic conditions
The electromagnetic conditions of the laboratory shall not influence the test results.
8.2 Execution of the test
The EUT shall be configured for its normal operating conditions.
The tests shall be performed according to a test plan that shall specify
− test number (see table 1);
− test level;
− test duration;
− ports to which the test shall be applied;
− representative operating conditions of the EUT;
− auxiliary equipment.
The power supply, signals and other functional electrical quantities shall be applied within their
rated range. If the actual operating signal sources are not available, they may be simulated.
For each test level, a succession of at least three unbalance sequences shall be applied, with
an interval of a least 3 min between each (see figure 2).
The applied test levels shall be rotated as follows:
to L , U to L , U to L ;
First sequence: U
a 1 b 2 c 3
Second sequence: U to L , U to L , U to L ;
a 2 b 3 c 1
Third sequence: U to L , U to L , U to L .
a 3 b 1 c 2
where
U , U and U (see table 1) are the voltages of the generator and
a b c
L , L and L are the inputs of the EUT.
1 2 3
Changes in supply voltage shall occur at zero crossings of U . The output impedance of the
a
test generator shall be low in steady state and during transition periods.

61000-4-27 © IEC:2000+A1:2009 – 11 –
For each test, any degradation of performance shall be recorded. The monitoring equipment
should be capable of displaying the status of the operational mode of the EUT during and after
the tests. After each group of tests a full functional check shall be performed.
9 Evaluation of test results
The test results shall be classified in terms of the loss of function or degradation of
performance of the equipment under test, relative to a performance level defined by its
manufacturer or the requestor of the test, or agreed between the manufacturer and the
purchaser of the product. The recommended classification is as follows:
a) normal performance within limits specified by the manufacturer, requestor or purchaser;
b) temporary loss of function or degradation of performance which ceases after the
disturbance ceases, and from which the equipment under test recovers its normal
performance, without operator intervention;
c) temporary loss of function or degradation of performance, the correction of which requires
operator intervention;
d) loss of function or degradation of performance which is not recoverable, owing to damage
to hardware or software, or loss of data.
The manufacturer's specification may define effects on the EUT which may be considered
insignificant, and therefore acceptable.
This classification may be used as a guide in formulating performance criteria, by committees
responsible for generic, product and product-family standards, or as a framework for the
agreement on performance criteria between the manufacturer and the purchaser, for example
where no suitable generic, product or product-family standard exists.
10 Test report
The test report shall contain all the information necessary to reproduce the test. In particular,
the following shall be recorded:
– the items specified in the test plan required by clause 8 of this standard;
– identification of the EUT and any associated equipment, e.g. brand name, product type,
serial number;
– identification of the test equipment, e.g. brand name, product type, serial number;
– any special environmental conditions in which the test was performed, e.g. shielded
enclosure;
– any specific conditions necessary to enable the test to be performed;
– performance level defined by the manufacturer, requestor or purchaser;
– performance criterion specified in the generic, product or product-family standard;
– any effects on the EUT observed during or after the application of the test disturbance, and
the duration for which these effects persist;
– the rationale for the pass/fail decision (based on the performance criterion specified in the
generic, product or product-family standard, or agreed between the manufacturer and the
purchaser);
– any specific conditions of use, for example cable length or type, shielding or grounding, or
EUT operating conditions, which are required to achieve compliance.

– 12 – 61000-4-27 © IEC:2000+A1:2009

L1 L2 L3
| | |
| | |
Ua
n
Ub
n
Uc
n
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
t
n
|
| Change at zero crossing
| of the undisturbed phase
IEC  1096/2000
Figure 1 – Example of unbalanced three-phase supply voltage (Test 3)
L1 L2 L3 L2 L3 L1 L3 L1 L2
| | | | | | | | |
| | | | | | | | |
0 0 0
0 0.02 0.04 0 0.02 0.04 0 0.02 0.04

←⎯⎯⎯⎯→←⎯⎯⎯⎯⎯⎯⎯→
minimum unbalance
of 180 s sequence of
duration t
IEC  1097/2000
Figure 2 – Succession of three unbalance sequences of the test
(the voltages U , U , U rotate)
a b c
NOTE These figures apply to 50 Hz systems.

61000-4-27 © IEC:2000+A1:2009 – 13 –

Three phase
power supply
Controller
Power
Waveform
Power
generator amplifier
Voltmeter
supply
E U T oscilloscope
Neutral (if
applicable)
IEC  1098/2000
Figure 3 – Schematic diagram of test instrumentation for unbalance

– 14 – 61000-4-27 © IEC:2000+A1:2009
Annex A
(informative)
Sources, effects and measurement of unbalance

A.1 Sources
The predominant cause of unbalance is single-phase loads.
In low-voltage networks, single-phase loads are almost exclusively connected phase-to-neutral
but they are distributed more or less equally among the three phases. In medium-voltage and
high-voltage networks, single-phase loads can be connected either phase-to-phase or phase-
to-neutral. Important single-phase loads include for example a.c. railway supplies or single-
phase induction furnaces. Some of the three-phase loads with an asymmetrical operating
regime, for example arc furnaces, cause unbalance.
High levels of unbalance for short periods of time are typically caused by faults in the network.
These faults occur mainly on the low-voltage network, but may also occur on the medium- and
high-voltage networks.
Depending on the characteristics of the protection equipment and the impedance of the
network, these faults result in different fault conditions as described in table 1.
A.2 Effects
Under unbalanced conditions, the impedance of a three-phase induction machine is similar to
its impedance during its starting (low-impedance) state, under which the current drawn by the
machine is very large, up to ten times the steady-state current. Consequently, a machine
operating on an unbalance supply will draw an unbalance current several times higher than the
supply voltage unbalanced. As a result, the three-phase currents may differ considerably and
the increased heating in the phase(s) with the higher current will only be partially offset by the
reduced heating in the other phases. As the temperature rises, the disconnection of one phase
may occur, a condition that can quickly result in the destruction of the machine.
Motors and generators, particularly the larger and more expensive types, may be fitted with
protection to detect this condition and disconnect the machine. If the supply unbalance is
sufficient, the "single-phasing" protection may respond to the unbalanced currents and trip the
machine.
Polyphase converters, in which the individual input phase voltages contribute in turn to the d.c.
output, will also be affected by an unbalanced supply, which causes an undesirable ripple
component on the d.c. side, and non-characteristic harmonics on the a.c. side.
Control equipment may also be disturbed, particularly where the design assumes only a
balanced supply network. In addition, sensors, for economic reasons, are often placed on only
one or two phases. Consequently, control and regulation errors occur, leading to possible
serious loss of performance.
61000-4-27 © IEC:2000+A1:2009 – 15 –
A.3 Measurement
A.3.1 Symmetrical components
The following method of symmetrical components is presented with reference to three-phase
systems, but also applies to polyphase systems.
A three-phase supply system is considered as unbalanced when the three related vectors used
to represent it, for example the voltage or current, are different in magnitude or when the phase
angles between consecutive vectors are not 120°. For those circuits under unbalanced
conditions, the method of symmetrical components has been adopted in order to simplify and
clarify the calculation of power system unbalanced faults, unbalanced loads and stability limits
on three-phase power systems.
This method reduces the three unbalanced related vectors (U , U and U in figure A.1) into
a b c
three sets of balanced vectors (U , U , U ; U , U , U ; U , U , U in figure A.2). The
1a 1b 1c 2a 2b 2c 0a 0b 0c
three vectors of each set are of equal magnitude and spaced either at 0° (figure A.2c) or 120°
(figures A.2a and A.2b). Each set (for example U , U , U ) is a symmetrical component of
1a 1b 1c
the original unbalanced vectors and is described as a positive-sequence, negative-sequence or
zero-sequence vector system. This concept applies to rotating vectors, such as voltages or
currents, or non-rotating vector operators such as impedance or admittance. We will refer here
to voltage rotating vectors.
The following example shows symmetrical vectors of amplitudes and phases typical of a fault
condition. Under normal operation conditions, for a system undergoing unbalanced conditions,
voltages U and U are typically a small per cent of U .
0 2 N
IEC  1099/2000
Figure A.1 – Unbalanced voltage vectors
U
U
1a
2b
U
a U
U
1c
0a
U
U
0b
2a
U
b
U
U
2c
0c
U
c
U
1b
IEC  1100/2000
a) Positive-sequence voltage  b) Negative-sequence voltage  c) Zero-sequence voltage
Figure A.2 – Components of the unbalanced vectors in figure A.1
The three sets of component vectors have the same (counter-clockwise) direction of rotation
as was assumed for the original unbalanced vectors. The negative sequence does not rotate in
a direction opposite to the positive sequence, but the phase sequence of the negative-
sequence set is opposite to the phase sequence of the positive-sequence set. The phase
sequence is the order in which the maximum values occur in the time domain.

– 16 – 61000-4-27 © IEC:2000+A1:2009
A.3.2 Negative and zero unbalance factors
A.3.2.1 Negative unbalance factor
Once the symmetrical components have been obtained from the unbalanced voltage system,
the degree of negative-sequence voltage unbalance can be determined using the ratio of the
negative-sequence component to the positive-sequence component. This ratio is commonly
called the unbalance factor (k ):
u2
= U /U
k
u2 2 1
where
U is the negative-sequence voltage;
U is the positive-sequence voltage.
The negative-sequence voltages are greatly attenuated when propagating from lower to higher
voltage networks. In the opposite direction (i.e. from higher to lower level), any attenuation
depends on the presence of three-phase rotating machines, which have a balancing effect.
The negative-sequence voltages in a network mainly result from the negative-sequence
currents of unbalanced loads flowing in the network.
A.3.2.2 Zero unbalance factor
In addition, the degree of zero-sequence voltage unbalance can be determined by the ratio of
the zero-sequence component to the positive-sequence component, the unbalance factor (k ):
u0
k = U /U
u0 0 1
where
U is the zero-sequence voltage;
U is the positive-sequence voltage.
The propagation of the zero-sequence unbalance voltage is stopped by the delta-connected
transformers.
The zero-sequence voltages mainly result from the zero-sequence currents of unbalanced
loads flowing in the network. They can affect three-phase equipment connected line-to-neutral,
but do not affect the majority of three-phase equipment which are connected line-to-line.
A.3.3 Measurement consideration
The voltage unbalance factors must be measured at the fundamental frequency (50 Hz or
60 Hz). If not, the contribution of the zero-sequence component, such as third harmonic
voltage, and/or the negative-sequence component, such as fifth harmonic voltage, can
increase the measured unbalance factor and consequently introduce an error because this
contribution does not cause the same effects as the fundamental frequency unbalance on
equipment.
61000-4-27 © IEC:2000+A1:2009 – 17 –
Annex B
(informative)
Calculation of the degree of unbalance

U
N
U cos()φ =[]k cos(φ ) + k cos()φ + k cos()φ
1 1 a a b b c c
U
N
()[]( ) () ()
U sin φ = k sin φ + k sin φ + k sin φ
1 1 a a b b c c
U ⎡ ⎤
⎛ 4π ⎞ ⎛ 2π ⎞
N
U cos()φ = k cos()φ + k cos φ − + k cos φ −
⎜ ⎟ ⎜ ⎟
2 2 a a b b c c
⎢ ⎥
3 3 3
⎝ ⎠ ⎝ ⎠
⎣ ⎦
U
⎡ ⎛ 4π ⎞ ⎛ 2π ⎞⎤
N
sin() sin() sin sin
U φ = k φ + k ⎜ φ − ⎟ + k ⎜ φ − ⎟
2 2 ⎢ a a b b c c ⎥
3 3 3
⎣ ⎝ ⎠ ⎝ ⎠⎦
where
k is the per cent of voltage on phase a, φ phase shift of phase a;
a a
k is the per cent of voltage on phase b, φ phase shift of phase b;
b b
k is the per cent of voltage on phase c, φ phase shift of phase c.
c c
2π 4π
⎛ ⎞ ⎛ ⎞
U = k U cos()wt + φ , U = k U cos⎜ wt − + φ ⎟, U = k U cos⎜ wt − + φ ⎟
a a N a b b N b c c N c
3 3
⎝ ⎠ ⎝ ⎠
Positive sequence:
U = U cos (φ ) + jU sin (φ )
1 1 1 1 1
Negative sequence:
U = U cos (φ ) + jU sin (φ )
2 2 2 2 2
Unbalance k :
u2
2 2
()()()()
U cos φ + U sin φ
2 2 2 2
U
k = =
u 2
U 2 2
()U cos()φ +()U sin(φ)
1 1 1 1
Ua
Ub
U2
U1
Uc
IEC  1101/2000
NOTE More information can be found in: Wagner, C.F., and Evans, R.D.: Symmetrical Components, Edition
R. KRIEGER.
– 18 – 61000-4-27 © IEC:2000+A1:2009
Annex C
(informative)
Information on test levels
Unbalanced currents generated by voltage unbalance can lead to serious damage of electrical
equipment.
A relatively intensive distortion of a three-phase system may occur for a short period especially
if a short circuit arises between two phases.
In this case, a very high current flow will cause a significant voltage drop and a phase shift of
these two phases. This will normally last until the circuit-breaker trips.
The severity of the fault determines the severity of the unbalance voltage. The duration of the
unbalance condition corresponds to the time reaction of the circuit breaker which is inversely
related to the severity of the fault.
The complex impedance used in IEC 60725 is Z = 0,24 + j 0,15 (phase conductor). The
i
characteristics of circuit breakers have been selected from IEC 60898, type D. From these
characteristics, the appropriate tests levels have been calculated.

61000-4-27 © IEC:2000+A1:2009 – 19 –
Annex D
(informative)
Electromagnetic environment classes

The following electromagnetic environment classes have been summarised from IEC 61000-2-4.
Class 1
This class applies to protected supplies and has compatibility levels lower than public network
levels. It relates to the use of equipment very sensitive to disturbances in the power supply, for
instance the instrumentation of technological laboratories, some automation and protection
equipment, some computers, etc.
NOTE
− Class 1 environments normally contain equipment which requires protection by such apparatus as
uninterruptible power supplies (UPS), filters, or surge suppressers.
− In some cases, highly sensitive equipment may require compatibility levels lower than the ones relevant to
class 1 environments. The compatibility levels are then to be agreed on a case by case basis.
Class 2
This class applies to points of common coupling (PCCs for consumer systems) and in-plant
points of common coupling (IPCs) in the industrial environment in general. The compatibility
levels in this class are identical to those of public networks; therefore components designed for
application in public networks may be used in this class of industrial environment.
Class 3
This class applies only to IPCs in industrial environments. It has higher compatibility levels
than those of class 2 for some disturbance phenomena. For instance, this class should be
considered when any of the following conditions are met:
− a major part of the load is fed through converters;
− welding machines are present;
− large motors are frequently started;
− loads vary rapidly
NOTE The supply to highly disturbing loads, such as arc-furnaces and large converters which are generally
supplied from a segregated bus-bar, frequently has disturbance levels in excess of class 3 (harsh environment). In
such special situations, the compatibility levels should be agreed upon.
The class applicable for new plants and extensions of existing plants should relate to the type
of equipment and process under consideration.

– 20 – 61000-4-27 © IEC:2000+A1:2009
Bibliography
IEC 60725, Considerations on reference impedances for use in determining the disturbance
characteristics of household appliances and similar electrical equipment
IEC 60898, Electrical accessories – Circuit-breakers for overcurrent protection for household
and similar installations
–––––––––
– 22 – 61000-4-27 © CEI:2000+A1:2009
SOMMAIRE
AVANT-PROPOS .23
INTRODUCTION.25

1 Domaine d’application et objet .26
2 Références normatives.26
3 Définitions.
...