SIST-TP CLC/TR 62271-208:2010

Methods to quantify the steady state, low frequency EMF generated by HV switchgear assemblies and HV/LV prefabricated substations (IEC/TR 62271-208:2009)

This part of IEC 62271 gives practical guidance for the evaluation and documentation of the external electromagnetic fields which are generated by HV switchgear assemblies and HV/LV prefabricated substations. Basic requirements to measure or calculate the electric and magnetic fields are summarised for switchgear assemblies covered by IEC 62271-200 and IEC 62271-201, and for prefabricated substations covered by IEC 62271-202. NOTE 1 The methods described in this technical report refer to three-phase equipment. However, the methodology may be used correspondingly for any single- or multi-phase equipment covered by this technical report. This technical report applies to equipment rated for voltages up to and including 52 kV and power-frequencies from 15 Hz to 60 Hz. The electromagnetic fields which are generated by harmonics or transients are not considered in this technical report. However, the methods described are equally applicable to the harmonic fields of the power-frequency. Detailed generic information on requirements and measurements of low-frequency electromagnetic fields is given in IEC 61786. This technical report covers evaluation under factory or laboratory conditions before installation. The electric and the magnetic fields can be evaluated either by measurements or by calculations. NOTE 2 Where practicable, the methods described in this technical report may also be used for installations on site. It is not within the scope of this technical report to specify limit values of electromagnetic fields or methods for the assessment of human exposure.

Bestimmung der stationären, betriebsfrequenten elektromagnetischen Felder von HS-Schaltanlagen und fabrikfertigen HS-/NS-Stationen (IEC/TR 62271-208:2009)

Méthodes de quantification des champs électromagnétiques à fréquence industrielle en régime établi générés par les ensembles d'appareillages HT et les postes préfabriqués HT/BT (CEI/TR 62271-208:2009)

La CEI/TR 62271-208:2009 donne des conseils pratiques pour évaluer et documenter les champs électromagnétiques externes générés par des appareillages HT et des postes HT/BT préfabriqués. Les exigences de base pour mesurer ou calculer les champs électrique et magnétique sont résumées pour des appareillages couverts par la CEI 62271-200 et la CEI 62271-201 et pour les postes préfabriqués couverts par la CEI 62271-202. Ce rapport technique s'applique aux équipements assignés pour des tensions jusqu'à et y compris 52 kV et des fréquences réseau de 15 Hz à 60 Hz.

Metode za kvantifikacijo nizkofrekvenčnih elektromagnetnih polj v ustaljenem stanju, ki jih generirajo visokonapetostne (VN) omrežne stikalne naprave in VN/NN montažne postaje (IEC/TR 62271-208:2009)

Ta del IEC 62271 podaja praktična vodila za ocenjevanje in dokumentacijo zunanjih elektromagnetnih polj, ki jih generirajo visokonapetostne omrežne stikalne naprave in VN/NN montažne postaje. Osnovne zahteve za merjenje ali izračun električnih in magnetnih polj so povzete za omrežne stikalne naprave, ki jih zajema IEC 62271-200 in IEC 62271-201, in za montažne postaje, ki jih zajema IEC 62271-202. OPOMBA 1: Metode, opisane v tem tehničnem poročilu, se nanašajo na trifazno opremo. Vendar pa se metodologija lahko ustrezno uporabi za katerokoli eno- ali večfazno opremo, ki jo zajema to tehnično poročilo. To tehnično poročilo se uporablja za opremo, opredeljeno za napetosti do in vključno z 52 kV in frekvence električnega toka od 15 Hz do 60 Hz. Elektromagnetska polja, ki jih generirajo harmonika (skladnost) ali prehodni pojavi, niso obravnavana v tem tehničnem poročilu. Vendar pa se opisane metode enakovredno uporabljajo za harmonična polja frekvence električnega toka. Podrobni splošni podatki o zahtevah in merjenih nizkofrekvenčnih elektromagnetnih polj so podani v IEC 61786. To tehnično poročilo zajema ocenjevanje pod tovarniškimi ali laboratorijskimi pogoji pred namestitvijo. Električna in magnetna polja se lahko ocenjuje bodisi z meritvami ali z izračuni. OPOMBA 2: Kjer je to izvedljivo, se lahko metode, opisane v tem tehničnem poročilu, uporabljajo tudi za naprave, postavljene na kraju obratovanja. Obseg tega tehničnega poročila ne zajema opredelitve mejnih vrednosti elektromagnetnih polj ali metod za ocenjevanje izpostavljenosti ljudi.

General Information

• Status: Published
• Publication Date: 06-May-2010
• ICS: 29.130.10 - High voltage switchgear and controlgear
• Technical Committee: SKA - Switchgear and control gear
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 29-Apr-2010
• Due Date: 04-Jul-2010
• Completion Date: 07-May-2010
• Ref Project: CLC/TR 62271-208:2010 - High-voltage switchgear and controlgear - Part 208: Methods to quantify the steady state, power-frequency electromagnetic fields generated by HV switchgear assemblies and HV/LV prefabricated substations

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CLC/TR 62271-208:2010
01-junij-2010
0HWRGH]DNYDQWLILNDFLMRQL]NRIUHNYHQþQLKHOHNWURPDJQHWQLKSROMYXVWDOMHQHP
VWDQMXNLMLKJHQHULUDMRYLVRNRQDSHWRVWQH91RPUHåQHVWLNDOQHQDSUDYHLQ9111
PRQWDåQHSRVWDMH,(&75
Methods to quantify the steady state, low frequency EMF generated by HV switchgear
assemblies and HV/LV prefabricated substations (IEC/TR 62271-208:2009)
Bestimmung der stationären, betriebsfrequenten elektromagnetischen Felder von HS-
Schaltanlagen und fabrikfertigen HS-/NS-Stationen (IEC/TR 62271-208:2009)
Méthodes de quantification des champs électromagnétiques à fréquence industrielle en
régime établi générés par les ensembles d'appareillages HT et les postes préfabriqués
HT/BT (CEI/TR 62271-208:2009)
Ta slovenski standard je istoveten z: CLC/TR 62271-208:2010
ICS:
29.130.10 Visokonapetostne stikalne in High voltage switchgear and
krmilne naprave controlgear
SIST-TP CLC/TR 62271-208:2010 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CLC/TR 62271-208:2010

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SIST-TP CLC/TR 62271-208:2010

TECHNICAL REPORT
CLC/TR 62271-208

RAPPORT TECHNIQUE
April 2010
TECHNISCHER BERICHT

ICS 29.130.10
English version
High-voltage switchgear and controlgear -
Part 208: Methods to quantify the steady state, power-frequency
electromagnetic fields generated by HV switchgear assemblies and HV/LV
prefabricated substations
(IEC/TR 62271-208:2009)
Appareillage à haute tension -  Hochspannungs-Schaltgeräte
Partie 208: Méthodes de quantification und -Schaltanlagen -
des champs électromagnétiques Teil 208: Bestimmung der stationären,
à fréquence industrielle en régime établi betriebsfrequenten elektromagnetischen
générés par les ensembles Felder von HS-Schaltanlagen
d'appareillages HT et les postes und fabrikfertigen HS-/NS-Stationen
préfabriqués HT/BT
(IEC/TR 62271-208:2009)
(CEI/TR 62271-208:2009)
This Technical Report was approved by CENELEC on 2010-03-05.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2010 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
-
Ref. No. CLC/TR 62271-208:2010 E

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SIST-TP CLC/TR 62271-208:2010
CLC/TR 62271-208:2010 – 2 –
Foreword
This Technical Report consists of the text of the International Technical Report
IEC/TR 62271-208:2009 prepared by SC 17C, High-voltage switchgear and controlgear assemblies,
of IEC TC 17, Switchgear and controlgear.
It was circulated for voting in accordance with the Internal Regulations, Part 2, Subclause 11.4.3.3
(simple majority) for acceptance as a CENELEC Technical Report.
__________

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Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
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.
NOTE  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 61000-6-2 - Electromagnetic compatibility (EMC) – EN 61000-6-2 -
Part 6-2: Generic standards – Immunity for
industrial environments
1)
IEC 61786 - Measurement of low-frequency magnetic and - -
electric fields with regard to exposure of human
beings – Special requirements for instruments
and guidance for measurement
1) 2)
IEC 62271-200 - High-voltage switchgear and controlgear – EN 62271-200 -
Part 200: AC metal-enclosed switchgear and
controlgear for rated voltages above 1 kV and
up to and including 52 kV
1) 2)
IEC 62271-201 - High-voltage switchgear and controlgear – EN 62271-201 -
Part 201: AC insulation-enclosed switchgear
and controlgear for rated voltages above 1 kV
and up to and including 52 kV
1) 2)
IEC 62271-202 - High-voltage switchgear and controlgear – EN 62271-202 -
Part 202: High voltage/low voltage prefabricated
substation


1)
Undated reference.
2)
Valid edition at date of issue.

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SIST-TP CLC/TR 62271-208:2010
IEC/TR 62271-208
®
Edition 1.0 2009-10
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
High-voltage switchgear and controlgear –
Part 208: Methods to quantify the steady state, power-frequency electromagnetic
fields generated by HV switchgear assemblies and HV/LV prefabricated
substations

Appareillage à haute tension –
Partie 208: Méthodes de quantification des champs électromagnétiques à
fréquence industrielle en régime établi générés par les ensembles
d’appareillages HT et les postes préfabriqués HT/BT

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 29.130.10 ISBN 2-8318-1067-8
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST-TP CLC/TR 62271-208:2010
– 2 – TR 62271-208 © IEC:2009
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms and definitions .8
4 Evaluation requirements .9
4.1 General .9
4.2 Methods of evaluation .9
4.3 Evaluation of electric fields.10
4.3.1 HV switchgear assemblies.10
4.3.2 HV/LV prefabricated substations.10
4.4 Evaluation of magnetic fields.10
4.4.1 HV switchgear assemblies.10
4.4.2 HV/LV prefabricated substations.11
5 Measurements.12
5.1 General .12
5.2 Measuring instruments .12
5.3 Measurement procedures .12
5.3.1 General .12
5.3.2 Electric field .13
5.3.3 Magnetic field .16
5.3.4 Background fields .16
5.3.5 Environmental factors.16
5.4 Measurement set-up.17
5.4.1 General .17
5.4.2 Additional provisions for HV/LV prefabricated substations .20
6 Calculations .20
6.1 General .20
6.2 Software.21
6.3 Calculation procedures.21
6.4 Results.21
6.5 Validation .22
7 Documentation .22
7.1 Characteristics of the HV switchgear assembly or prefabricated substation .22
7.2 Evaluation method.22
7.3 Presentation of the measurement results.22
7.4 Presentation of the calculation results .23
Annex A (informative) Presentation of E or B field measurement data – Example for a
typical HV/LV pre-fabricated substation .24
Annex B (informative) Examples of analytical solutions to benchmark EMF
27
calculations.
Bibliography.45

Figure 1 – Example of test circuits configuration to obtain the maximum external
magnetic field of a switchgear assembly and/or a prefabricated substation .11
Figure 2 – Reference surface (RS) for equipment of irregular shape .13

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TR 62271-208 © IEC:2009
Figure 3 – Scanning areas to find the hot spots .14
Figure 4 – Determination of the field variation as a function of the distance from the
hot spot locations (perpendicular to the reference surface) .15
Figure 5 – Test set-up of main components, external cables, hot spot locations and
measurement volume.18
Figure 6 – Test circuit for electric and magnetic field measurement .19
Figure A.1 – Hot spot locations representing the field maxima .24
Figure A.2 – Graphical presentation of the field variation .25
Figure A.3 – Example diagram for the field variation at hot spots .26
Figure B.1 – Schematic for 3-phase magnetic field calculation.27
Figure B.2 – Variation of resultant magnetic field around 3-phase cable .30
Figure B.3 – Maximum resultant magnetic field around 3-phase cable .31
Figure B.4 – Schematic for 3-phase electric field calculation.35
Figure B.5 – Variation of resultant electric field around 3-phase cable .38
Figure B.6 – Maximum resultant electric field around 3-phase cable .40

Table A.1 – Listing of the hot spot coordinates.25
Table A.2 – Variation of field values for one hot spot .25
Table A.3 – Background fields .26
Table B.1 – Values of H for spatial angles θ and time angles ωt .30
res
Table B.2 – Values of maximum H for spatial angles θ.32
res
Table B.3 – Values of E for spatial angles θ and time angles ωt.39
res
Table B.4 – Values of maximum E for spatial angles θ .40

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 208: Methods to quantify the steady state,
power-frequency electromagnetic fields
generated by HV switchgear assemblies
and HV/LV prefabricated substations


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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62271-208, which is a technical report, has been prepared by subcommittee 17C: High-
voltage switchgear and controlgear assemblies, of IEC technical committee 17: Switchgear
and controlgear.
In this technical report the word “shall” is used as a conditional “shall”, in the event that this
technical report is applied.

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TR 62271-208 © IEC:2009
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
17C/450/DTR 17C/462/RVC

Full information on the voting for the approval of this technical report 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.
A list of all the parts in the IEC 62271 series, under the general title High-voltage switchgear
and controlgear, can be found on the IEC website.
The committee has decided that the contents of this publication 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.

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INTRODUCTION
Manufacturers of electricity supply equipment may be asked to provide information about the
electromagnetic field characteristics to enable the user to
• assess the electromagnetic field conditions to assist with planning, installation, operating
instructions and service,
• take measures to meet requirements or regulations on electromagnetic fields,
• compare different products as far as their level of electromagnetic fields is concerned.
The purpose of this technical report is to describe a methodology for the evaluation
(measurement or calculation) of generated electromagnetic fields.
The electromagnetic field characteristic of the equipment comprises the values of the electric
and the magnetic fields around its accessible surfaces.
The electromagnetic field characteristic defined in this technical report refers to a single
product as defined in the scope. In real installations, several field sources can superimpose,
so the resulting electromagnetic fields on site may differ significantly from the single product
characteristics.
This technical report does not define a mandatory test for the products mentioned in the
scope.
Neither the establishment of limits for the electromagnetic fields generated by equipment, nor
the establishment of assessment methods for the human exposure to electromagnetic fields is
within the content or intent of this technical report.

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TR 62271-208 © IEC:2009
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 208: Methods to quantify the steady state,
power-frequency electromagnetic fields
generated by HV switchgear assemblies
and HV/LV prefabricated substations



1 Scope
This part of IEC 62271 gives practical guidance for the evaluation and documentation of the
external electromagnetic fields which are generated by HV switchgear assemblies and HV/LV
prefabricated substations. Basic requirements to measure or calculate the electric and
magnetic fields are summarised for switchgear assemblies covered by IEC 62271-200 and
IEC 62271-201, and for prefabricated substations covered by IEC 62271-202.
NOTE 1 The methods described in this technical report refer to three-phase equipment. However, the
methodology may be used correspondingly for any single- or multi-phase equipment covered by this technical
report.
This technical report applies to equipment rated for voltages up to and including 52 kV and
power-frequencies from 15 Hz to 60 Hz. The electromagnetic fields which are generated by
harmonics or transients are not considered in this technical report. However, the methods
described are equally applicable to the harmonic fields of the power-frequency.
Detailed generic information on requirements and measurements of low-frequency
electromagnetic fields is given in IEC 61786.
This technical report covers evaluation under factory or laboratory conditions before
installation. The electric and the magnetic fields can be evaluated either by measurements or
by calculations.
NOTE 2 Where practicable, the methods described in this technical report may also be used for installations on
site.
It is not within the scope of this technical report to specify limit values of electromagnetic
fields or methods for the assessment of human exposure.
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 61000-6-2, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards - Immunity
for industrial environments
IEC 61786, Measurement of low-frequency magnetic and electric fields with regard to
exposure of human beings – Special requirements for instruments and guidance for
measurements
IEC 62271-200, High-voltage switchgear and controlgear – Part 200: AC metal-enclosed
switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

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IEC 62271-201, High-voltage switchgear and controlgear – Part 201: AC insulation-enclosed
switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV
IEC 62271-202, High-voltage switchgear and controlgear – Part 202: High-voltage/low-voltage
prefabricated substation
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
EMF
abbreviation for the term “electromagnetic field(s)”
3.2
electric field characteristic
values (r.m.s.) and spatial distribution of the electric field strength at rated voltage and
frequency around all accessible surfaces of the equipment. The electric field characteristic is
the resultant of the r.m.s. values of the three orthogonal vector components
3.3
magnetic field characteristic
values (r.m.s.) and spatial distribution of the magnetic flux density at rated normal current and
frequency around all accessible surfaces of the equipment. The magnetic field characteristic
is the resultant of the r.m.s. values of the three orthogonal vector components
NOTE The terms “resultant electric field” and “resultant magnetic field” are defined in IEC 61786.
3.4
accessible surfaces
those parts of the walls and roof of prefabricated substations or HV switchgear assemblies
that can be touched with all covers and doors in closed position in normal service conditions
3.5
reference surface
RS
virtual envelope containing the equipment for evaluation purposes
3.6
measurement surface
MS
defined outside the reference surface at 20 cm distance
NOTE This surface is used for measuring the hot spots and the variation of the EMF.
3.7
hot spot
centre of an area of a local maximum of the electric or the magnetic field
3.8
EMF characteristic
spatial distribution of the resultant (modulus) of the r.m.s. electric field strength (E) and the
magnetic flux density (B). The spatial distribution is derived from a measurement or
calculation grid

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3.9
measurement volume
MV
virtual space in which the electromagnetic background field must not exceed an appropriate
level to permit the uninfluenced measurement of the electric and magnetic fields generated by
the equipment
4 Evaluation requirements
4.1 General
The EMF characteristic of HV switchgear assemblies or HV/LV prefabricated substations is
the measured or calculated electric field strength and magnetic flux density around all
accessible surfaces under the conditions for evaluation described below. These conditions
represent the service, where the loading of the switchgear assemblies and, in a substation, of
the transformer is at defined values.
As the electric and magnetic fields are dependent on the physical arrangement of incoming
and outgoing cables and their loadings, these parameters have to be recorded. The presence
of other field sources and shielding or other metallic structures shall be recorded.
The EMF characteristic shall be evaluated for the conditions that would result in the highest
levels of electric and magnetic fields in normal, undisturbed service. These conditions include
the highest currents and largest loops realistically possible through the assembly working at
maximum capacity. EMF caused by switching operations, including interruption of fault
currents, or other transient phenomena is deemed to be incidental and shall not be
considered.
The highest current on the HV side is the rated normal current given on the nameplate of the
switchgear assembly, and on the LV side the rated normal current of the transformer with the
highest rating. In a calculation both currents have to be simulated. During a measurement it is
preferable to have both currents present.
Electric field strength and magnetic flux density shall be recorded as the resultant of the
r.m.s. values of the three orthogonal components.
The evaluation shall be carried out at the rated frequency of the equipment.
However, in the frequency range up to and including 60 Hz the actual value of frequency does
not significantly affect the levels of generated E fields for any given values of voltage.
Therefore evaluation at any frequency up to and including 60 Hz is considered valid.
Similarly, the difference in attenuation of B fields by metallic enclosures at 50 Hz and 60 Hz
can be ignored for the purpose of this technical report. Therefore evaluation at 50 Hz is
considered applicable also for 60 Hz and vice versa.
In the power-frequency range covered by this technical report the electric and magnetic fields
may be treated separately. When selecting the conditions to obtain the highest level of
electric and magnetic fields as realistically as possible in undisturbed service, the following
subclauses shall be considered.
4.2 Methods of evaluation
The manufacturer may evaluate the EMF characteristic by measurement or by calculation.

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4.3 Evaluation of electric fields
4.3.1 HV switchgear assemblies
The equipment shall be evaluated at the rated voltage of the HV switchgear assembly.
Only if the evaluation cannot be carried out at rated voltage, the results shall be extrapolated
to the rated value. Since the electric field strength is a linear function of the voltage, the field
strengths for different high voltages may be extrapolated linearly.
4.3.2 HV/LV prefabricated substations
The equipment shall be evaluated at the rated high voltage of the HV/LV transformer(s).
Only if the evaluation cannot be carried out at rated voltage, the results shall be extrapolated
to the rated value. Since the electric field strength is a linear function of the voltage, the field
strengths for different high voltages may be extrapolated linearly.
4.4 Evaluation of magnetic fields
4.4.1 HV switchgear assemblies
The HV switchgear assembly is loaded with its highest permissible current determined by the
rated normal current given on the nameplate. The HV circuit must be selected to form the
widest possible current loop between the incomin
...