EN 61000-2-12:2003
(Main)Electromagnetic compatibility (EMC) - Part 2-12: Environment - Compatibility levels for low-frequency conducted disturbances and signalling in public medium-voltage power supply systems
Electromagnetic compatibility (EMC) - Part 2-12: Environment - Compatibility levels for low-frequency conducted disturbances and signalling in public medium-voltage power supply systems
This part of EN 61000 is concerned with conducted disturbances in the frequency range from 0 kHz to 9 kHz, with an extension up to 148,5 kHz specifically for mains signalling systems. Compatibility levels are specified for electromagnetic disturbances of the types which can be expected in public medium voltage power supply systems, for guidance in: a) the limits to be set for disturbance emission into public power supply systems (including the planning levels defined in 3.1.5); b) the immunity limits to be set by product committees and others for the equipment exposed to the conducted disturbances present in public power supply systems. The disturbance phenomena considered are: voltage fluctuations and flicker, harmonics up to and including order 50, inter-harmonics up to the 50th harmonic, voltage distortions at higher frequencies (above 50th harmonic), voltage dips and short supply interruptions, voltage unbalance, transient overvoltages, power frequency variation, d.c. components, mains signalling. The medium-voltage systems covered by this standard are public distribution systems supplying either: a) private installations in which equipment is connected directly or through transformers, or b) substations feeding public low-voltage distribution systems.
Elektromagnetische Verträglichkeit - Teil 2-12: Umgebungsbedingungen - Verträglichkeitspegel für niederfrequente leitungsgeführte Störgrößen und Signalübertragung in öffentlichen Mittelspannungsnetzen
Compatibilité électromagnétique (CEM) - Partie 2-12: Environnement - Niveaux de compatibilité pour les perturbations conduites à basse fréquence et la transmission des signaux sur les réseaux publics d'alimentation moyenne tension
La présente partie de la EN 61000 s'applique aux perturbations conduites dans le domaine de fréquence de 0 kHz à 9 kHz, avec une extension jusqu'à 148,5 kHz pour les systèmes de transmission de signaux sur le réseau. Les niveaux de compatibilité sont donnés pour les types de perturbations électromagnétiques auxquelles on peut s'attendre sur les réseaux de distribution publics moyenne tension, dans le but d'aider à définir: a) les limites devant être établies pour les émissions perturbatrices sur les réseaux publics de distribution d'énergie (comprenant également les niveaux de planification tels que définis en 3.1.5); b) les limites d'immunité devant être établies par les comités de produit ou autres concernant les équipements soumis aux perturbations conduites par les réseaux publics de distribution d'énergie. Les phénomènes perturbateurs considérés sont: les fluctuations de tension et le flicker, les harmoniques jusque et y compris le rang 50, les interharmoniques jusqu'au rang 50, les distorsions de tension aux fréquences supérieures (au-dessus du rang 50), les creux de tension et les coupures brèves, le déséquilibre de tension, les surtensions transitoires, les variations de fréquence, les composantes continues, les systèmes de transmission de signaux sur le réseau. Les réseaux moyenne tension couverts par cette norme sont des réseaux de distribution publics alimentant: a) soit des installations privées dans lesquelles le matériel est raccordé directement ou à travers de transformateurs, b) soit des postes de transformation alimentant des réseaux de distribution publics basse tension.
Electromagnetic compatibility (EMC) -- Part 2-12: Environment - Compatibility levels for low-frequency conducted disturbances and signalling in public medium-voltage power supply systems (IEC 61000-2-12:2003)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2003
Electromagnetic compatibility (EMC) -- Part 2-12: Environment - Compatibility
levels for low-frequency conducted disturbances and signalling in public medium-
voltage power supply systems (IEC 61000-2-12:2003)
Electromagnetic compatibility (EMC) -- Part 2-12 : Environment - Compatibility levels for
low-frequency conducted disturbances and signalling in public medium-voltage power
supply systems
Elektromagnetische Verträglichkeit -- Teil 2-12: Umgebungsbedingungen -
Verträglichkeitspegel für niederfrequente leitungsgeführte Störgrößen und
Signalübertragung in öffentlichen Mittelspannungsnetzen
Compatibilité électromagnétique (CEM) -- Partie 2-12: Environnement - Niveaux de
compatibilité pour les perturbations conduites à basse fréquence et la transmission des
signaux sur les réseaux publics d'alimentation moyenne tension
Ta slovenski standard je istoveten z: EN 61000-2-12:2003
ICS:
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 61000-2-12
NORME EUROPÉENNE
EUROPÄISCHE NORM July 2003
ICS 33.100.01
English version
Electromagnetic compatibility (EMC)
Part 2-12 : Environment –
Compatibility levels for low-frequency conducted disturbances and
signalling in public medium-voltage power supply systems
(IEC 61000-2-12:2003)
Compatibilité électromagnétique (CEM) Elektromagnetische Verträglichkeit
Partie 2-12: Environnement – Teil 2-12: Umgebungsbedingungen -
Niveaux de compatibilité pour Verträglichkeitspegel für niederfrequente
les perturbations conduites à basse leitungsgeführte Störgrößen und
fréquence et la transmission des signaux Signalübertragung in öffentlichen
sur les réseaux publics d'alimentation Mittelspannungsnetzen
moyenne tension (IEC 61000-2-12:2003)
(CEI 61000-2-12:2003)
This European Standard was approved by CENELEC on 2003-06-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61000-2-12:2003 E
Foreword
The text of document 77A/404/FDIS, future edition 1 of IEC 61000-2-12, prepared by SC 77A, Low
frequency phenomena, of IEC TC 77, Electromagnetic compatibility, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 61000-2-12 on 2003-06-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-03-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-06-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annexes A and B are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61000-2-12:2003 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60038 NOTE Harmonized as HD 472 S1:1989 (modified).
IEC 60868 NOTE Harmonized as HD 498 S1:1987 (not modified).
IEC 60868-0 NOTE Harmonized as EN 60868-0:1993 (not modified).
IEC 61000-3-2 NOTE Harmonized as EN 61000-3-2:2000 (modified).
IEC 61000-3-3 NOTE Harmonized as EN 61000-3-3:1995 (not modified).
__________
- 3 - EN 61000-2-12:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60071 Series Insulation co-ordination EN 60071 Series
1) 2)
IEC 60071-1 - Insulation co-ordination EN 60071-1 1995
Part 1: Definitions, principles and rules
1) 2)
IEC 61000-2-2 - Electromagnetic compatibility (EMC) EN 61000-2-2 2002
Part 2-2: Environment - Compatibility
levels for low-frequency conducted
disturbances and signalling in public
low-voltage power supply systems
1) 2)
IEC 61000-2-4 - Part 2-4: Environment - Compatibility EN 61000-2-4 2002
levels in industrial plants for low-
frequency conducted disturbances
1) 2)
IEC 61000-4-7 - Part 4-7: Testing and measurement EN 61000-4-7 2002
techniques - General guide on
harmonics and interharmonics
measurements and instrumentation, for
power supply systems and equipment
connected thereto
1)
Undated reference.
2)
Valid edition at date of issue.
NORME CEI
INTERNATIONALE IEC
61000-2-12
INTERNATIONAL
Première édition
STANDARD
First edition
2003-04
Compatibilité électromagnétique (CEM) –
Partie 2-12:
Environnement – Niveaux de compatibilité
pour les perturbations conduites à basse
fréquence et la transmission des signaux
sur les réseaux publics d'alimentation
moyenne tension
Electromagnetic compatibility (EMC) –
Part 2-12:
Environment – Compatibility levels for
low-frequency conducted disturbances and
signalling in public medium-voltage power
supply systems
IEC 2003 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 any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
U
Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue
61000-2-12 IEC:2003 – 3 –
CONTENTS
FOREWORD . 5
INTRODUCTION .9
1 Scope and object .11
2 Normative references.13
3 Terms and definitions.13
3.1 General definitions.13
3.2 Phenomena related definitions .15
4 Compatibility levels .19
4.1 General comment .19
4.2 Voltage fluctuations and flicker.21
4.3 Harmonics .21
4.4 Interharmonics and voltage components at frequencies above that of the
th
50 harmonic.23
4.5 Voltage dips and short supply interruptions.23
4.6 Voltage unbalance .25
4.7 Transient overvoltages.25
4.8 Temporary power frequency variation.25
4.9 DC component.25
4.10 Mains signalling .27
Annex A (informative) The function of compatibility levels and planning levels in EMC.31
A.1 The need for compatibility levels .31
A.2 Relation between compatibility level and immunity levels .31
A.3 Relation between compatibility level and emission limits .33
A.4 Planning levels.37
A.5 Illustration of compatibility, emission, immunity and planning levels .37
Annex B (informative) Discussion of some disturbance phenomena .41
B.1 Resolution of non-sinusoidal voltages and currents .41
th
B.2 Interharmonics and voltage components at frequencies above that of the 50
harmonic.45
B.3 Voltage dips and short supply interruptions.51
B.4 Transient overvoltages.53
B.5 DC component.53
Bibliography .55
61000-2-12 IEC:2003 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 2-12: Environment –
Compatibility levels for low-frequency conducted disturbances and
signalling in public medium-voltage power supply systems
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 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 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 61000-2-12 has been prepared by subcommittee 77A: Low
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
It has the status of a 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/404/FDIS 77A/413/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 2.
61000-2-12 IEC:2003 – 7 –
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
61000-2-12 IEC:2003 – 9 –
INTRODUCTION
IEC 61000 is published in separate parts 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 the 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 a second
number identifying the subdivision (example: 61000-6-1).
Detailed information on the various types of disturbances that can be expected on public power
supply systems can be found in IEC 61000-2-1.
61000-2-12 IEC:2003 – 11 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 2-12: Environment –
Compatibility levels for low-frequency conducted disturbances and
signalling in public medium-voltage power supply systems
1 Scope and object
This part of IEC 61000 is concerned with conducted disturbances in the frequency range from
0 kHz to 9 kHz, with an extension up to 148,5 kHz specifically for mains signalling systems. It
gives compatibility levels for public medium voltage a.c. distribution systems having a nominal
voltage between 1 kV and 35 kV and a nominal frequency of 50 Hz or 60 Hz (see IEC 60038).
Compatibility levels are specified for electromagnetic disturbances of the types which can be
expected in public medium voltage power supply systems, for guidance in:
a) the limits to be set for disturbance emission into public power supply systems (including the
planning levels defined in 3.1.5);
b) the immunity limits to be set by product committees and others for the equipment exposed
to the conducted disturbances present in public power supply systems.
The disturbance phenomena considered are:
• voltage fluctuations and flicker;
• harmonics up to and including order 50;
th
• inter-harmonics up to the 50 harmonic;
th
• voltage distortions at higher frequencies (above 50 harmonic);
• voltage dips and short supply interruptions;
• voltage unbalance;
• transient overvoltages;
• power frequency variation;
• d.c. components;
• mains signalling.
Most of these phenomena are described in IEC 61000-2-1. In cases where it is not yet possible
to establish compatibility levels, some information is provided.
The medium-voltage systems covered by this standard are public distribution systems
supplying either:
a) private installations in which equipment is connected directly or through transformers, or
b) substations feeding public low-voltage distribution systems.
61000-2-12 IEC:2003 – 13 –
The compatibility levels specified in this standard apply at the point of common coupling in the
case of (a) and at the medium-voltage terminals of the substation in the case of (b). See
Clause 4.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60071(all parts), Insulation co-ordination
IEC 60071-1, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 61000-2-2, Electromagnetic compatibility (EMC) – Part 2-2: Environment – Compatibility
levels for low-frequency conducted disturbances and signalling in public low-voltage power
supply systems
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2-4: Environment – Compatibility
levels in industrial plants for low-frequency conducted disturbances
IEC 61000-4-7, Electromagnetic compatibility (EMC) – Part 4-7: Testing and measurement
techniques – General guide on harmonics and interharmonics measurements and
instrumentation, for power supply systems and equipment connected thereto
3 Terms and definitions
For the purpose of this present document, the following definitions apply.
3.1 General definitions
3.1.1
(electromagnetic) disturbance
any electromagnetic phenomenon which, by being present in the electromagnetic environment,
can cause electrical equipment to depart from its intended performance
[IEV 161-01-05 modified]
3.1.2
disturbance level
the amount or magnitude of an electromagnetic disturbance, measured and evaluated in a
specified way
[IEV 161-03-01 modified]
3.1.3
electromagnetic compatibility
EMC (abbreviation)
ability of an equipment or system to function satisfactorily in its electromagnetic environment
without introducing intolerable electromagnetic disturbances to anything in that environment
NOTE 1 Electromagnetic compatibility is a condition of the electromagnetic environment such that, for every
phenomenon, the disturbance emission level is sufficiently low and immunity levels are sufficiently high so that all
devices, equipment and systems operate as intended.
61000-2-12 IEC:2003 – 15 –
NOTE 2 Electromagnetic compatibility is achieved only if emission and immunity levels are controlled such that
the immunity levels of the devices, equipment and systems at any location are not exceeded by the disturbance
level at that location resulting from the cumulative emissions of all sources and other factors such as circuit
impedances. Conventionally, compatibility is said to exist if the probability of the departure from intended
performance is sufficiently low. See Clause 4 of IEC 61000-2-1.
NOTE 3 Where the context requires it, compatibility may be understood to refer to a single disturbance or class of
disturbances.
NOTE 4 Electromagnetic compatibility is a term used also to describe the field of study of the adverse
electromagnetic effects which devices, equipment and systems undergo from each other or from electromagnetic
phenomena.
[IEV 161-01-07 modified]
3.1.4
(electromagnetic) compatibility level
specified electromagnetic disturbance level used as a reference level in a specified
environment for co-ordination in the setting of emission and immunity limits
NOTE By convention, the compatibility level is chosen so that there is only a small probability that it will be
exceeded by the actual disturbance level.
[IEV 161-03-10 modified]
3.1.5
planning level
level of a particular disturbance in a particular environment, adopted as a reference value for
the limits to be set for the emissions from large loads and installations, in order to co-ordinate
those limits with all the limits adopted for equipment intended to be connected to the power
supply system
NOTE The planning level is locally specific, and is adopted by those responsible for planning and operating the
power supply network in the relevant area. (For further information, see Annex A.)
3.1.6
point of common coupling
PCC
point on a public power supply network, electrically nearest to a particular load, at which other
loads are, or could be, connected
[IEV 161-07-15 modified]
3.2 Phenomena related definitions
The definitions below that relate to harmonics are based on the analysis of system voltages or
currents by the Discrete Fourier Transform method (DFT). This is the practical application of
the Fourier transform as defined in IEV 101-13-09. See Annex B.
NOTE The Fourier Transform of a function of time, whether periodic or non-periodic, is a function in the frequency
domain and is referred to as the frequency spectrum of the time function, or simply spectrum. If the time function is
periodic the spectrum is constituted of discrete lines (or components). If the time function is not periodic, the
spectrum is a continuous function, indicating components at all frequencies.
Other definitions related to harmonics or interharmonics are given in the IEV and other
standards. Some of those other definitions, although not used in this standard, are discussed in
Annex B.
61000-2-12 IEC:2003 – 17 –
3.2.1
fundamental frequency
frequency in the spectrum obtained from a Fourier transform of a time function, to which all the
frequencies of the spectrum are referred. For the purpose of this standard, the fundamental
frequency is the same as the power supply frequency
NOTE 1 In the case of a periodic function, the fundamental frequency is generally equal to the frequency of the
function itself. (See Annex B.1).
NOTE 2 In case of any remaining risk of ambiguity, the power supply frequency should be referred to the polarity
and speed of rotation of the synchronous generator(s) feeding the system.
[IEV 101-14-50, modified]
3.2.2
fundamental component
component whose frequency is the fundamental frequency
3.2.3
harmonic frequency
frequency which is an integer multiple of the fundamental frequency. The ratio of the harmonic
frequency to the fundamental frequency is the harmonic order (recommended notation: “h”)
3.2.4
harmonic component
any of the components having a harmonic frequency. Its value is normally expressed as an
r.m.s. value
For brevity, such a component may be referred to simply as an harmonic
3.2.5
interharmonic frequency
any frequency which is not an integer multiple of the fundamental frequency
NOTE 1 By extension from harmonic order, the interharmonic order is the ratio of an interharmonic frequency to
the fundamental frequency. This ratio is not an integer. (Recommended notation “m”).
NOTE 2 In the case where m< 1 the term subharmonic frequency may be used.
3.2.6
interharmonic component
component having an interharmonic frequency. Its value is normally expressed as an r.m.s.
value
For brevity, such a component may be referred to simply as an “interharmonic”
NOTE For the purpose of this standard and as stated in IEC 61000-4-7, the time window has a width of 10
fundamental periods (50 Hz systems) or 12 fundamental periods (60 Hz systems), i.e. approximately 200 ms. The
difference in frequency between two consecutive interharmonic components is, therefore, approximately 5 Hz.
3.2.7
total harmonic distortion
THD
ratio of the r.m.s. value of the sum of all the harmonic components up to a specified order
(recommended notation “H”) to the r.m.s. value of the fundamental component
h=H
Q
h
THD =
∑
Q
h=2 1
61000-2-12 IEC:2003 – 19 –
where
Q represents either current or voltage
Q = r.m.s. value of the fundamental component
h = harmonic order
Q = r.m.s. value of the harmonic component of order h
h
H = 50 generally, but 25 when the risk of resonance at higher orders is low.
NOTE THD takes account of harmonics only. For the case where interharmonics are to be included, see B.1.2.1,
Annex B.
3.2.8
voltage unbalance (imbalance)
condition in a polyphase system in which the r.m.s. values of the line-to-line voltages
(fundamental component), or the phase angles between consecutive line-to-line voltages, are
not all equal. The degree of the inequality is usually expressed as the ratios of the negative and
zero sequence components to the positive sequence component
[IEV 161-08-09 modified]
NOTE 1 In this standard, voltage unbalance is considered in relation to three-phase systems and negative phase
sequence only.
NOTE 2 Several approximations give reasonably accurate results for the levels of unbalance normally encountered
(ratio of negative to positive sequence components):
2 2 2
6()U + U + U
12 23 31
Voltage unbalance = − 2
()
U + U + U
12 23 31
where U , U and U are the three line-to-line voltages.
12 23 31
4 Compatibility levels
4.1 General comment
The following subclauses set down compatibility levels for the various disturbances on an
individual basis only. However, the electromagnetic environment usually contains several
disturbances simultaneously, and the performance of some equipment can be degraded by
particular combinations of disturbances. See Annex A.
At the power input terminals of equipment receiving its supply from the medium-voltage
distribution systems covered by this standard, the severity levels of the disturbances can, for
the most part, be taken to be the same as the levels at the point of common coupling. In some
situations this is not so, particularly in the following cases:
• a long line dedicated to the supply of a particular installation;
• equipment being part of an extensive installation;
• a disturbance generated or amplified within the installation of which the equipment forms a
part.
In the case of medium voltage networks associated with downstream low voltage networks, the
actual disturbance levels are usually lower on the medium voltage networks than on the low
voltage networks. This is especially the case for harmonics and interharmonics. Exceptions can
arise from causes such as resonance and the aggregation of disturbances from other parts of
the network. Given the co-ordination function of compatibility levels, it is important that they
reflect the disturbance levels that have a significant probability of being encountered in
practice, although that probability is quite low.
61000-2-12 IEC:2003 – 21 –
The MV compatibility level is not intended to be representative of average conditions, but must
take account of exceptional conditions that have a significant risk of being encountered. This is
necessary to ensure that it is a useful reference value in specifying immunity levels for
equipment that will be connected to MV networks. It is very important, however, to note the
following:
• emission and immunity limits for equipment supplied from public low-voltage distribution
systems are co-ordinated on the basis of low-voltage compatibility levels specified in
IEC 61000-2-2;
• limits for the emissions from large loads and installations are co-ordinated on the basis of
planning levels – see 3.1.6 and Annex A; see also the technical reports IEC 61000-3-6 and
IEC 61000-3-7;
• emission and immunity limits for equipment supplied from non-public distribution systems
are co-ordinated on the basis of compatibility levels specified in IEC 61000-2-4.
Accordingly, despite the fact that there is usually a margin between the disturbance levels on
MV and LV networks, this standard specifies MV compatibility levels that are the same as those
specified in IEC 61000-2-2.
4.2 Voltage fluctuations and flicker
Voltage fluctuations on the medium voltage networks are produced by fluctuating loads,
operation of transformer tap changers and other operational adjustments of the supply system
or equipment connected to it.
In normal circumstances the value of rapid voltage changes is limited to 3 % of nominal supply
voltage. However step voltage changes exceeding 3 % can occur infrequently on the public
supply network.
Furthermore, following exceptional load changes or switching operations, voltage excursions
outside the normal operational tolerances (e.g., ±10 % of declared supply voltage) are possible
for a few tens of seconds until on-load tap-changers on the high voltage-medium voltage
transformers have operated.
Voltage fluctuations in medium voltage networks, by being transferred, with or without
alteration, to low voltage networks, can cause flicker. See IEC 61000-2-2 for compatibility
levels in low-voltage networks.
4.3 Harmonics
In specifying compatibility levels for harmonics, two facts must be considered. One is that the
number of harmonic sources is increasing. The other is that the proportion of purely resistive
loads (heating loads), which function as damping elements, is decreasing in relation to the
overall load. Therefore increasing harmonic levels are to be expected in power supply systems
until the sources of harmonic emissions are brought under effective limits.
The compatibility levels in this standard shall be understood to relate to quasi-stationary or
steady-state harmonics, and are given as reference values for both long-term effects and very
short-term effects.
• The long-term effects relate mainly to thermal effects on cables, transformers, motors,
capacitors, etc. They arise from harmonic levels that are sustained for 10 min or more.
61000-2-12 IEC:2003 – 23 –
• Very short-term effects relate mainly to disturbing effects on electronic devices that may be
susceptible to harmonic levels sustained for 3 s or less. Transients are not included.
With reference to long-term effects the compatibility levels for individual harmonic components
of the voltage are given in Table 1. The corresponding compatibility level for the total harmonic
distortion is THD = 8 %.
Table 1 – Compatibility levels for individual harmonic voltages in medium voltage
networks (r.m.s. values as percent of r.m.s. value of the fundamental component)
Odd harmonics Odd harmonics Even harmonics
Non-multiple of 3 Multiple of 3
Harmonic Harmonic Harmonic Harmonic Harmonic Harmonic
order voltage order voltage order voltage
h % h % h %
56 3 5 2 2
75 9 1,5 4 1
11 3,5 15 0,4 6 0,5
13 3 21 0,3 8 0,5
0,2
17≤ h ≤ 49 2,27 × (17/h) – 0,27 21 < h ≤ 45 10 ≤ h ≤ 50 0,25 × (10/h) + 0,25
NOTE 1 The levels given for odd harmonics that are multiples of three apply to zero sequence harmonics.
Also, on a three-phase network without a neutral conductor or without load connected between line and
rd th
ground, the values of the 3 and 9 harmonics may be much lower than the compatibility levels, depending
on the unbalance of the system.
NOTE 2 Lower values are often appropriate – See 4.1
With reference to very short-term effects, the compatibility levels for individual harmonic
components of the voltage are the values given in Table 1, multiplied by a factor k, where k is
as follows:
0,7
k = 1,3 + ×()h − 5
The corresponding compatibility level for the total harmonic distortion is THD = 11 %.
NOTE Commutation notches, in so far as they contribute to harmonic levels in the supply voltage, are covered by
the compatibility levels given above. In relation to their other effects, however, including their influence on the
commutation of other converters and their effects on other equipment involving the higher order harmonic
components, a time-domain description is required – see the relevant product standard.
4.4 Interharmonics and voltage components at frequencies above that of the
th
50 harmonic
Knowledge of the electromagnetic disturbance involved in interharmonic and higher frequency
voltages is still developing. See Annex B for further discussion.
Compatibility levels relating to the flicker effect associated with this phenomenon on low
voltage networks are given in IEC 61000-2-2.
4.5 Voltage dips and short supply interruptions
For a discussion of these phenomena, see Annex B, and IEC 61000-2-8.
61000-2-12 IEC:2003 – 25 –
4.6 Voltage unbalance
In this standard voltage unbalance is considered only in relation to the negative phase
sequence component, this being the component relevant to possible interference with
equipment connected to public medium voltage distribution systems.
NOTE For systems with the neutral point directly connected to earth, the zero-sequence unbalance ratio can be
relevant.
The voltage unbalance caused by a single-phase load connected line-to-line is in practice
equal to the ratio of the load power to the network three-phase short circuit power.
The compatibility level for unbalance is a negative sequence component of 2 % of the positive
sequence component. In some areas, especially where it is the practice to connect large
single-phase loads, values up to 3 % may occur.
4.7 Transient overvoltages
For a discussion of these phenomena, see Annex B.
Compatibility levels are not given for transient overvoltages in this standard. However, for
insulation co-ordination see IEC 60071.
4.8 Temporary power frequency variation
In public power supply systems the frequency is maintained as close as possible to the nominal
frequency, but the extent to which that is possible depends mainly on the aggregate size of the
systems which are interconnected synchronously. For the most part, the range is within 1 Hz of
the nominal frequency. Where synchronous interconnection is implemented on a continental
scale, the variation is usually very much less. Island systems, not synchronously connected to
large systems, can undergo somewhat greater variation.
The compatibility level for the temporary variation of frequency from the nominal frequency is
±1Hz.
The steady-state deviation of frequency from the nominal frequency is much less.
NOTE For some equipment the rate of change of frequency is significant.
4.9 DC component
The voltage of public power supply systems covered by this standard does not normally have a
d.c. component at a significant level. That can arise, however, when certain non-symmetrically
controlled loads are connected.
The critical point is the level of d.c. current. The value of the d.c. voltage depends upon not
only d.c. current but also other factors, especially the resistance of the network at the point to
be considered. Therefore a compatibility level for the d.c. voltage is not specified.
See Annex B.
61000-2-12 IEC:2003 – 27 –
4.10 Mains signalling
Although public networks are intended primarily for the supply of electric energy to customers,
the suppliers also use them for the transmission of signals for purposes such as the control of
some categories of load (these networks are not used for the transmission of signals between
private users).
Technically, mains signalling is a source of interharmonic voltages – see 4.4 and Annex B. In
this case, however, the signal voltage is intentionally impressed on a selected part of the
supply system. The voltage and frequency of the emitted signal are pre-determined, and the
signal is transmitted at particular times.
For co-ordination of the immunity of equipment connected to networks on which mains signals
exist, the voltage levels of these signals need to be taken into account.
Design of mains signalling systems should meet three objectives:
• to assure compatibility between neighbouring installations,
• to avoid interference with the mains signalling system and its elements by equipment on or
connected to the network.
• to prevent the mains signalling system from disturbing equipment on or connected to the
network.
Four types of mains signalling systems are described in Clause 10 of IEC 61000-2-1 (the
frequency ranges mentioned are nominal and are a matter of common practice).
4.10.1 Ripple control systems (110 Hz to 3 000 Hz)
Ripple control signals are transmitted as a sequence of pulses, each pulse having a duration in
the range 0,1 s to 7 s, and the duration of the entire sequence ranging from 6 s to 180 s. More
usually, the pulse duration is about 0,5 s, and the sequence duration is about 30 s.
Generally, these systems operate in the frequency range of 110 Hz to 3000 Hz. The value of
the injected sine wave signal is in the region 2 % to 5 % of the nominal supply voltage,
depending on local practice, but resonance can cause levels to rise to 9 %. On more recently
installed systems the signals usually are in the range of 110 Hz to 500 Hz.
In some countries the so-called Meister curve, given in Figure 1, is officially recognised. Where
the Meister curve is not applied, the amplitudes of signals within this frequency range should
not exceed the levels given in Table 1 for odd harmonics (non-multiples of 3).
61000-2-12 IEC:2003 – 29 –
1,5
0,1
0,1 0,5 1 310
Frequency kHz
IEC 1184/03
Figure 1 – Meister curve for ripple control systems in public networks
(100 Hz to 3 000 Hz)
4.10.2 Medium-frequency power-line carrier systems (3 kHz to 20 kHz)
Under consideration.
4.10.3 Radio-frequency power-line carrier systems (20 kHz to 148,5 kHz)
Under consideration.
4.10.4 Mains-mark systems
Because of the different characteristics of the various systems, no general guidance can be
given and it is for manufacturers to ensure compatibility between their systems and the supply
network.
Signal level Us/Un %
61000-2-12 IEC:2003 – 31 –
Annex A
(informative)
The function of compatibility levels and planning levels in EMC
A.1 The need for compatibility levels
Electromagnetic compatibility (EMC) is concerned with the possible degradation of the
performance of electrical and electronic equipment due to the disturbances present in the
electromagnetic environment in which the equipment operates. For compatibility, there are two
essential requirements:
• the emission of disturbances into the electromagnetic environment must be maintained
below a level that would cause an unacceptable degradation of the performance of
equipment operating in that environment;
• all equipment operating in the electromagnetic environment must have sufficient immunity
from all disturbances at the levels at which they exist in the environment.
Limits for emission and immunity cannot be set independently of each other. Clearly, the more
effectively emissions are controlled, the less restrictive are the immunity demands that have to
be placed on equipment. Similarly, if equipment is highly immune, there is less need for
stringent limits on the emission of disturbances.
There is a requirement, therefore, for close co-ordination between the limits adopted for
emission and immunity. That is the principal function of the compatibility levels specified in this
standard.
The disturbance phenomena covered are those that are conducted on the medium voltage
networks of public ac power supply systems. In effect, the supply system, which is intended to
be the channel through which electrical energy is conveyed from the generating stations to the
utilising equipment, also, unintentionally, is made the channel through which electromagnetic
disturbances are conveyed from their sources to the equipment affected by them.
Three considerations have been borne in mind in setting the compatibility level for each
phenomenon:
• the compatibility level is the level of the disturbance which can be expected in the
environment, allowing for a small probability (< 5 %) of its being exceeded. For some
disturbance phenomena severity levels are rising, and therefore a long-term perspective is
required;
• it is a disturbance level which can be maintained by implementing practicable limits on
emissions;
• it is the level of disturbance from which, with a suitable margin, equipment operating in the
relevant environment must have immunity.
A.2 Relation between compatibility level and immunity levels
For each disturbance phenomenon, the compatibility level must be recognised as the level of
severity which can exist in the relevant environment. All equipment intended for operation in
that environment requires to have immunity at least at that level of disturbance. Normally a
margin will be provided between the compatibility and immunity levels, appropriate to the
equipment concerned.
61000-2-12 IEC:2003 – 33 –
Moreover, the compatibility levels have been set for the individual disturbance phenomena,
and, in the case of harmonics and interharmonics, for individual frequencies. It must be
recognised, however, that it is normal for several disturbance phenomena to co-exist in the
environment, and that it is possible that the performance of some equipment can be degraded
by a particular combination of disturbances, although each is at a level less than the
compatibility level.
For example, in the case of harmonics and interharmonics, certain combinations of frequency,
magnitude, and phasing can substantially alter the magnitude of the voltage peak and/or the
point of zero crossing. Further complications can be added by the presence of other
disturbances.
Because the number of permutations is infinite, it is not possible to set compatibility levels for
combinations of disturbances.
Therefore if, within the compatibility lev
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