EN IEC 62271-207:2023

SLOVENSKI STANDARD
01-februar-2024
Visokonapetostne stikalne in krmilne naprave - 207. del: Seizmična (potresna)
kvalifikacija plinsko izoliranih stikalnih sestavov v kovinskih ohišjih in stikalnih
sestavov v ohišjih iz trdnih izolacijskih materialov za naznačene napetosti nad 1
kV (IEC 62271-207:2023)
High-voltage switchgear and controlgear - Part 207: Seismic qualification for gas-
insulated switchgear assemblies, metal enclosed and solid-insulation enclosed
switchgear for rated voltages above 1 kV (IEC 62271-207:2023)
Hochspannungs-Schaltgeräte und -Schaltanlagen – Teil 207: Erdbebenqualifikation für
gasisolierte Schaltgerätekombinationen, metallgekapselte und isolierstoffgekapselte
Schaltanlagen mit Bemessungsspannungen über 1 kV (IEC 62271-207:2023)
Appareillage à haute tension - Partie 207: Qualification sismique pour les ensembles
d'appareillage de commutation à isolation gazeuse, à enveloppe métallique et à isolation
solide pour des tensions nominales supérieures à 1 kV (IEC 62271-207:2023)
Ta slovenski standard je istoveten z: EN IEC 62271-207:2023
ICS:
29.130.10 Visokonapetostne stikalne in High voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62271-207

NORME EUROPÉENNE
EUROPÄISCHE NORM December 2023
ICS 29.130.10 Supersedes EN 62271-207:2012
English Version
High-voltage switchgear and controlgear - Part 207: Seismic
qualification for gas-insulated switchgear assemblies, metal
enclosed and solid-insulation enclosed switchgear for rated
voltages above 1 kV
(IEC 62271-207:2023)
Appareillage à haute tension - Partie 207: Qualification Hochspannungs-Schaltgeräte und -Schaltanlagen - Teil
sismique des ensembles d'appareillages à isolation 207: Erdbebenqualifikation für gasisolierte
gazeuse et des appareillages sous enveloppe métallique et Schaltgerätekombinationen, metallgekapselte und
sous enveloppe isolante solide pour des tensions assignées isolierstoffgekapselte Schaltanlagen mit
supérieures à 1 kV Bemessungsspannungen über 1 kV
(IEC 62271-207:2023) (IEC 62271-207:2023)
This European Standard was approved by CENELEC on 2023-12-14. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62271-207:2023 E

European foreword
The text of document 17C/902/FDIS, future edition 3 of IEC 62271-207, prepared by SC 17C
"Assemblies" of IEC/TC 17 "High-voltage switchgear and controlgear" was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN IEC 62271-207:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-09-14
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-12-14
document have to be withdrawn
This document supersedes EN 62271-207:2012 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62271-207:2023 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 standard indicated:
IEC 62271-207:2012 NOTE Approved as EN 62271-207:2012 (not modified)
IEC 62155 NOTE Approved as EN 62155
IEC 62231 NOTE Approved as EN 62231
IEC 61462 NOTE Approved as EN IEC 61462
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60068-2-47 - Environmental testing - Part 2-47: Test - EN 60068-2-47 -
Mounting of specimens for vibration, impact
and similar dynamic tests
IEC 60068-2-57 2013 Environmental testing - Part 2-57: Tests - EN 60068-2-57 2013
Test Ff: Vibration - Time-history and sine-
beat method
IEC 60068-3-3 2019 Environmental testing - Part 3-3: Supporting EN IEC 60068-3-3 2019
documentation and guidance - Seismic test
methods for equipment
IEC 60099-4 2014 Surge arresters - Part 4: Metal-oxide surge EN 60099-4 2014
arresters without gaps for a.c. systems
IEC 62271-1 2017 High-voltage switchgear and controlgear - EN 62271-1 2017
Part 1: Common specifications for alternating
current switchgear and controlgear
IEC 62271-200 2021 High-voltage switchgear and controlgear - EN IEC 62271-200 2021
Part 200: AC metal-enclosed switchgear and
controlgear for rated voltages above 1 kV
and up to and including 52 kV
IEC 62271-201 2014 High-voltage switchgear and controlgear - EN 62271-201 2014
Part 201: AC solid-insulation enclosed
switchgear and controlgear for rated voltages
above 1 kV and up to and including 52 kV
IEC 62271-203 2022 High-voltage switchgear and controlgear - EN IEC 62271-203 2022
Part 203: AC gas-insulated metal-enclosed
switchgear for rated voltages above 52 kV
ISO 2041 - Mechanical vibration, shock and condition - -
monitoring - Vocabulary
IEC 62271-207 ®
Edition 3.0 2023-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
High-voltage switchgear and controlgear –

Part 207: Seismic qualification for gas-insulated switchgear assemblies, metal

enclosed and solid-insulation enclosed switchgear for rated voltages above 1 kV

Appareillage à haute tension –

Partie 207: Qualification sismique des ensembles d'appareillages à isolation

gazeuse et des appareillages sous enveloppe métallique et sous enveloppe

isolante solide pour des tensions assignées supérieures à 1 kV

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.10  ISBN 978-2-8322-7776-8

– 2 – IEC 62271-207:2023 © IEC 2023
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Seismic qualification requirements . 11
4.1 Seismic qualification objective . 11
4.2 Qualification levels . 11
4.3 Selection of seismic qualification level . 14
4.3.1 General . 14
4.3.2 Estimation of site-specific seismic hazard level . 14
4.3.3 Effect of building response and elevation . 15
4.3.4 Soil-structure interaction . 15
5 Qualification by test . 15
5.1 General . 15
5.2 Mounting . 16
5.3 Test parameters . 16
5.3.1 Measurements . 16
5.3.2 Frequency range . 16
5.3.3 Parameters for resonant frequency search . 17
5.3.4 Parameters for time history test (seismic load test) . 17
5.4 Testing procedure . 17
5.4.1 General . 17
5.4.2 Inspection and functional checks . 17
5.4.3 Resonant frequency search . 18
5.4.4 Time history test (seismic load test) . 18
6 Qualification by combined test and numerical analysis . 19
6.1 General . 19
6.2 Dynamic and functional data . 19
6.3 Numerical analysis . 20
6.3.1 General . 20
6.3.2 Analytical earthquake component combination techniques . 20
6.3.3 Static analysis for rigid equipment . 21
6.3.4 Static coefficient analysis . 21
6.3.5 Dynamic response spectrum analysis . 21
6.3.6 Time history analysis . 22
6.4 Analysis by experience or similarity . 22
7 Evaluation of the seismic qualification . 23
7.1 Combination of loads and stresses. 23
7.2 Validity criteria for the seismic waveform and the seismic test . 24
7.3 Structural and functional evaluation of the test results . 24
7.3.1 Common criteria for HV switchgear and MV switchgear . 24
7.3.2 HV switchgear . 24
7.3.3 MV switchgear . 25
7.4 Allowable stresses . 25
7.5 Criteria of model acceptance. 25
7.6 Acceptance criteria of the analysis results by similarity . 25

IEC 62271-207:2023 © IEC 2023 – 3 –
8 Documentation . 26
8.1 Test report . 26
8.2 Analysis report . 26
8.3 Analysis report when analysis is performed by similarity . 28
Annex A (normative) Characterisation of the test-set . 29
A.1 Low-level excitation . 29
A.1.1 General . 29
A.1.2 Test method . 29
A.1.3 Analysis . 29
A.2 Determination of the damping ratio by testing . 29
A.2.1 General . 29
A.2.2 Determination of the damping ratio by free oscillation test . 29
A.2.3 Determination of the damping ratio by measuring the half-power

bandwidth . 31
A.2.4 Determination of the damping ratio by curve fitting to frequency
response methods . 31
A.2.5 Determination of the damping ratio by time domain curve fitting . 31
Annex B (informative) Criteria for seismic adequacy of enclosed switchgear and
controlgear assemblies . 32
B.1 General . 32
B.2 Foundations . 32
B.3 Methods for anchoring equipment to foundations . 32
B.4 Interconnection to adjacent equipment . 33
B.5 Use of bracings on switchgear structure . 33
Annex C (informative) Qualification process flowchart . 34
Bibliography . 35

Figure 1 – Required response spectrum (RRS) for qualification level AG2.5
(ZPA = 0,25 g) . 13
Figure 2 – Required response spectrum (RRS) for qualification level AG5
(ZPA = 0,50 g) . 13
Figure 3 – Required response spectrum (RRS) for qualification level AG10
(ZPA = 1,00 g) . 14
Figure A.1 – Monogram for the determination of equivalent damping ratio . 30
Figure C.1 – Qualification process flowchart . 34

Table 1 – Seismic qualification levels for switchgear and controlgear assemblies –
Horizontal severities . 11
Table 2 – Comparison of qualification levels between various standards . 12
Table 3 – Summary of maximum stresses, loads etc. . 27
Table 4 – Example of summary of maximum stresses, loads etc. . 28

– 4 – IEC 62271-207:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 207: Seismic qualification for gas-insulated switchgear assemblies,
metal-enclosed and solid-insulation enclosed switchgear
for rated voltages above 1 kV
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,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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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
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62271-207 has been prepared by subcommittee 17C: Assemblies, of IEC technical
committee 17: High-voltage switchgear and controlgear. It is an International Standard.
This third edition cancels and replaces the second edition published in 2012. This edition
constitutes a technical revision. It also cancels and replaces, through merging, the first edition
of IEC TS 62271-210 published in 2013.
This edition includes the following significant technical changes with respect to the previous
edition:
a) modification of the minimum voltage rating from 52 kV to above 1 kV in order to include
medium voltage equipment previously being within IEC TS 62271-210 scope;

IEC 62271-207:2023 © IEC 2023 – 5 –
b) further harmonisation of qualification procedures with the revised IEEE Std 693-2018 [1] ,
Annex A and Annex P, including
1) matching this document's required response spectra with IEEE Std 693-2018
performance level spectra and IEC TS 62271-210 spectra,
2) addition of a step-by-step procedure assisting the user of this document to select an
appropriate seismic qualification level combining seismic integrity with cost-effective
design,
3) addition of analytical earthquake component combination techniques, and
4) reference to publicly available accelerograms specially developed to match the
IEEE Std 693-2018 spectra for testing and analysis purposes, since this document and
IEC TS 62271-210 spectra are identical in shape with IEEE Std 693 spectra.
c) various enhancements of test procedures;
d) addition of minimum contents for seismic qualification reports;
e) scope extended to cover DC GIS including and above 100 kV.
The text of this International Standard is based on the following documents:
Draft Report on voting
17C/902/FDIS 17C/916/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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 document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

___________
Numbers in square brackets refer to the Bibliography.

– 6 – IEC 62271-207:2023 © IEC 2023
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 207: Seismic qualification for gas-insulated switchgear assemblies,
metal-enclosed and solid-insulation enclosed switchgear
for rated voltages above 1 kV
1 Scope
This part of IEC 62271 applies to
– gas-insulated switchgear (GIS) assemblies
• for alternating current of rated voltages above 52 kV complying with IEC 62271-203, and
• for direct current of rated voltages including and above 100 kV,
• for indoor and outdoor installations, including their supporting structures,
– AC metal-enclosed switchgear and controlgear assemblies for rated voltages above 1 kV
and up to and including 52 kV complying with IEC 62271-200, ground or floor mounted,
intended to be used under seismic conditions, and
– AC solid-insulation enclosed switchgear and controlgear assemblies for rated voltages
above 1 kV and up to and including 52 kV complying with IEC 62271-201, ground or floor
mounted, intended to be used under seismic conditions.
The seismic qualification of the switchgear and controlgear assemblies takes into account
testing of typical switchgear and controlgear assemblies combined with methods of analysis.
Mutual interaction between directly mounted auxiliary and control equipment and switchgear
assemblies is considered.
Seismic qualification philosophy includes selection of seismic qualification level (Clause 4),
methodologies for qualification by testing (Clause 5) and by combined testing and analysis
(Clause 6), acceptance criteria (Clause 7) and seismic qualification documentation (Clause 8).
Recommendations on increasing the seismic adequacy of switchgear and controlgear
assemblies are provided in Annex B. A flowchart of the seismic qualification process is included
in Annex C.
The seismic qualification of switchgear and controlgear assemblies by the manufacturer is
performed usually if needed.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 60068-2-47, Environmental testing – Part 2-47: Tests – Mounting of specimens for
vibration, impact and similar dynamic tests
IEC 60068-2-57:2013, Environmental testing – Part 2-57: Tests – Test Ff: Vibration –
Time-history and sine-beat method
IEC 60068-3-3:2019, Environmental testing – Part 3-3: Supporting documentation and guidance
– Seismic test methods for equipment

IEC 62271-207:2023 © IEC 2023 – 7 –
IEC 60099-4:2014, Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c.
systems
IEC 62271-1:2017, High-voltage switchgear and controlgear – Part 1: Common specifications
for alternating current switchgear and controlgear
IEC 62271-200:2021, 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
IEC 62271-201:2014, High-voltage switchgear and controlgear – Part 201: AC solid-insulation
enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including
52 kV
IEC 62271-203:2022, High-voltage switchgear and controlgear – Part 203: AC gas-insulated
metal-enclosed switchgear for rated voltages above 52 kV
ISO 2041, Mechanical vibration, shock and condition monitoring – Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60068-3-3,
IEC 62271-1, IEC 62271-200, IEC 62271-201, IEC 62271-203, ISO 2041 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
switchgear and controlgear
switching devices and their combination with associated control, measuring, protective and
regulating equipment, including assemblies of such devices and equipment with associated
interconnections, accessories, enclosures and supporting structures
[SOURCE: IEC 60050-441:1984, 441-11-01]
3.2
metal-enclosed switchgear and controlgear
switchgear and controlgear assemblies with an external metal enclosure intended to be earthed,
and complete except for external connections
[SOURCE: IEC 60050-441:1984, 441-12-04, modified – Note deleted.]
3.3
gas-insulated metal-enclosed switchgear
GIS
metal-enclosed switchgear in which the insulation is obtained, at least partly, by an insulating
gas or gas mixture other than air at atmospheric pressure
[SOURCE: IEC 60050-441:1984, 441-12-05, modified – Abbreviated term "GIS" added. Words
"or gas mixture" added to the definition, and note deleted.]

– 8 – IEC 62271-207:2023 © IEC 2023
3.4
solid-insulation enclosed switchgear and controlgear
switchgear and controlgear assemblies with an external solid insulating enclosure and
completely assembled, except for external connections
[SOURCE: IEC 62271-201:2014, 3.103 – Note deleted.]
3.5
high voltage switchgear
HV switchgear
gas-insulated switchgear (GIS) assemblies for alternating current of rated voltages above 52 kV
complying with IEC 62271-203 and for direct current of rated voltages including and above
100 kV, for indoor and outdoor installations, including their supporting structure
Note 1 to entry: The upcoming IEC TS 62271-318 [9] is expected to regulate DC GIS of rated voltages including
and above 100 kV.
3.6
medium voltage switchgear
MV switchgear
AC metal-enclosed switchgear and controlgear assemblies for rated voltages above 1 kV and
up to and including 52 kV complying with IEC 62271-200 and AC solid-insulation enclosed
switchgear and controlgear assemblies for rated voltages above 1 kV and up to and including
52 kV complying with IEC 62271-201, ground or floor mounted
3.7
user
utility, customer, final owner of the qualified equipment
3.8
brittle material
material that experiences limited or no plastic deformation before fracture
Note 1 to entry: Limited deformation shall be taken as less than 10 % in 5 cm at failure in tension.
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.9
ductile material
material that experiences considerable plastic deformation before fracture
Note 1 to entry: Considerable plastic deformation is defined as 10 % or greater in 5 cm at failure in tension.
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.10
flexible equipment
equipment, structures, and components whose lowest resonant frequency is less than 33 Hz
3.11
rigid equipment
equipment, structures, and components whose lowest resonant frequency is greater than 33 Hz
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]

IEC 62271-207:2023 © IEC 2023 – 9 –
3.12
acceleration of gravity
g
acceleration due to gravity that is 9,81 m/s
Note 1 to entry: For the purposes of this document, the value of g is rounded up to the nearest integer, that is
10 m/s .
3.13
ground acceleration
acceleration of the ground resulting from the motion of a given earthquake
3.14
peak ground acceleration
PGA
maximum ground acceleration of any component of the time history
3.15
zero period acceleration
ZPA
zero period acceleration is the spectral acceleration for frequencies above 33 Hz
3.16
floor acceleration
acceleration of a particular building floor (or an equipment mounting) resulting from its response
to the ground motion of a given earthquake
3.17
response spectrum
plot of the maximum response of an array of single-degree-of-freedom (SDOF) identically
damped oscillators with different frequencies, all subjected to the same base excitation
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.18
required response spectrum
RRS
response spectrum that defines the required level of input motion for a given level of
qualification
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.19
floor response spectrum
response spectrum of the floor acceleration history of a building floor (or an equipment
mounting)
Note 1 to entry: Response acceleration spectra can be calculated for each one of the three components of
excitation.
3.20
superelevation factor
amplification factor accounting for the amplification of seismic loading with respect to ground
level due to the response of buildings and structures
Note 1 to entry: A superelevation factor is used in lieu of a more accurate estimation of the contribution of the
building (or other equipment mounting) response to the response of the qualified equipment.

– 10 – IEC 62271-207:2023 © IEC 2023
3.21
resonant frequency
frequency coinciding with the natural frequency of a system (at which the response amplitude
is a relative maximum)
Note 1 to entry: At a resonant frequency, even small periodic driving forces can produce large amplitude oscillations
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.22
complete quadratic combination method
CQC method
modal combination method, especially useful for systems with closely spaced frequencies
[SOURCE: IEEE Std 693-2018. Adapted and reprinted with permission from IEEE. Copyright
IEEE 2018. All rights reserved.]
3.23
damping
energy dissipation mechanisms in a system
Note 1 to entry: In practice, damping depends on many parameters, such as the structural system, mode of
vibration, strain, applied forces, velocity, materials, joint slippage.
[SOURCE: IEC 60068-3-3:2019, 3.8, modified – Second note to entry deleted.]
3.23.1
critical damping
minimum viscous damping that will allow a displaced system to return to its initial position
without oscillation
[SOURCE: IEC 60068-3-3:2019, 3.8.1]
3.23.2
damping ratio
ratio of actual damping to critical damping in a system with viscous damping
[SOURCE: IEC 60068-3-3:2019, 3.8.2]
3.24
direction factor
factor taking account of the difference in magnitude at ground level that normally exists between
the horizontal and vertical accelerations resulting from an earthquake
[SOURCE: IEC 60068-3-3:2019, 3.9]
3.25
normal operating load
force, stress, or load resulting from equipment operation that can reasonably be expected to
occur during an earthquake
IEC 62271-207:2023 © IEC 2023 – 11 –
3.26
seismic qualification level
level of seismic excitation to which equipment shall maintain the seismic qualification objective
Note 1 to entry: The seismic qualification level is dependent upon the seismicity of the region where the equipment
will be in service.
Note 2 to entry: Information on comparison between seismic levels for different standards is given in Table 2.
3.27
time history
recording, as a function of time, of acceleration or velocity or displacement
Note 1 to entry: This definition is not identical to that given in ISO 2041.
[SOURCE: IEC 60068-3-3:2019, 3.34]
3.28
strong part of time history
part of time history from the time when the plot first reaches 25 % of the maximum value to the
time when it falls for the last time to the 25 % level
[SOURCE: IEC 60068-3-3:2019, 3.27]
4 Seismic qualification requirements
4.1 Seismic qualification objective
The seismic qualification shall demonstrate the ability of the switchgear and controlgear
assemblies to withstand seismic stress without impairing the functionality of the equipment
during and after seismic events. It may be proved by testing or by a combination of testing and
analysis.
4.2 Qualification levels
A seismic qualification level is defined as the magnitude of seismic excitation to which
equipment shall maintain the seismic qualification objective. The qualification shall be done on
one of the four seismic qualification levels of Table 1: low, AG2.5, AG5 and AG10.
Qualification levels are associated with ZPA of the required response spectrum. For the low
qualification level, the horizontal ZPA is 0,10 g or less. For the AG2.5 qualification level, the
ZPA is 0,25 g. For the AG5 qualification level, the ZPA is 0,50 g. For the AG10 qualification
level, the ZPA is 1,00 g.
NOTE Seismic qualification level AG10 is a very severe requirement which can need the consideration of special
measures such as reinforcement of the gantry/enclosure and application of high-strength insulators, so caution is
advised when applying.
Table 1 – Seismic qualification levels for switchgear and controlgear assemblies –
Horizontal severities
Qualification Required response Zero period acceleration
level spectrum (RRS) (ZPA)
Low ---
≤ 1,0m/s (0,10 g)
AG2.5 Figure 1
2,5 m/s (0,25 g)
AG5 Figure 2
5,0 m/s (0,50 g)
AG10 Figure 3
10 m/s (1,00 g)
– 12 – IEC 62271-207:2023 © IEC 2023
A comparison between the qualification levels of this document and the qualification levels of
IEC 62271-207:2012, IEC TS 62271-210:2013 and IEEE Std 693-2018 is presented on Table 2.
ZPA is used as basis for the comparison.
Table 2 – Comparison of qualification levels between various standards
ZPA This document IEC 62271-207:2012 [2] IEC TS 62271-210:2013 [3] IEEE Std 693-2018
Low Low - Low
≤ 1,0 m/s
(0,10 g)
AG2.5 Moderate - -
2,5 m/s
(0,25 g)
AG5 High Severity level 1 Moderate performance level
5,0 m/s
(0,50 g)
AG10 - Severity level 2 High performance level
10,0 m/s
(1,00 g)
The fixed seismic qualification levels of Table 1 are practical for standardization purposes and
testing. Typical examples are medium voltage metal-enclosed and solid-insulation enclosed
switchgear and controlgear assemblies.
In the case of custom layout applications such as high voltage GIS substations comprising
constellations of standardized GIS modules combined with gas-insulated busducts (GIB) that
can span up to several hundred meters and are supported by custom-made steel structures,
consideration of local seismic hazard level could enable a cost-effective and seismically safe
design. In that sense, other qualification levels which consist in requirements from the user that
can be based on specific investigation at site or regulations in national standards, taking into
account for example the type of soil, soil structure interaction, building response, and elevation
may be used as described in 4.3.
The selection of the seismic qualification level is the responsibility of the user and is normally
based on an assessment of site geophysical parameters, seismic hazard, risk assessments,
and economics.
No qualification is required for low seismic level as far as construction practice and seismic
construction practice comply with the state of the art. The recommended required response
spectra related to the horizontal components of the seismic excitation are given in Figure 1,
Figure 2 and Figure 3 for the different seismic qualification levels. The curves relate to 2 % and
5 % damping ratio of the switchgear and controlgear assemblies. If damping ratio is unknown,
2 % damping is applied for high voltage switchgear or 5 % damping for medium voltage
switchgear. The corresponding response spectra related to the vertical component of excitation
are defined as 80 % of the horizontal ones.
Response spectra for different damping values may be calculated by applying the formulae
provided in Figure 1 through Figure 3.

IEC 62271-207:2023 © IEC 2023 – 13 –

Spectral accelerations, S (g), for frequencies, f (Hz):
a
S = 0,572 β f for 0,0 ≤ f ≤ 1,1
a
S = 0,625 β  for 1,1 ≤ f ≤ 8,0
a
S = (6,6 β – 2,64) / f – 0,2 β + 0,33 for 8,0 ≤ f ≤ 33
a
S = 0,25  for f > 33
a
β = (3,21 – 0,68 ln(d)) / 2,1156, where d is the percent damping (2, 5, 10, etc.) and d ≤ 20 %
[SOURCE: Adapted and reprinted with permission from IEEE. Copyright IEEE 2018. All rights reserved.]
Figure 1 – Required response spectrum (RRS) for qualification level AG2.5
(ZPA = 0,25 g)
Spectral accelerations, S (g), for frequencies, f (Hz):
a
S = 1,144 β f for 0,0 ≤ f ≤ 1,1
a
S = 1,25 β  for 1,1 ≤ f ≤ 8,0
a
S = (13,2 β – 5,28) / f – 0,4 β + 0,66 for 8,0 ≤ f ≤ 33
a
S = 0,50  for f > 33
a
β = (3,21 – 0,68 ln(d)) / 2,1156, where d is the percent damping (2, 5, 10, etc.) and d ≤ 20 %
[SOURCE: Adapted and reprinted with permission from IEEE. Copyright IEEE 2018. All rights reserved.]
Figure 2 – Required response spectrum (RRS) for qualification level AG5 (ZPA = 0,50 g)

– 14 – IEC 62271-207:2023 © IEC 2023

Spectral accelerations, S (g), for frequencies, f (Hz):
a
S = 2,288 β f for 0,0 ≤ f ≤ 1,1
a
S = 2,50 β  for 1,1 ≤ f ≤ 8,0
a
S = (26,4 β – 10,56) / f – 0,8 β + 1,32 for 8,0 ≤ f ≤ 33
a
S = 1,00  for f > 33
a
β = (3,21 – 0,68 ln(d)) / 2,1156, where d is the percent damping (2, 5, 10, etc.) and d ≤ 20 %
[SOURCE: Adapted and reprinted with permission from IEEE. Copyright IEEE 2018. All rights reserved.]
Figure 3 – Required response spectrum (RRS) for qualification level AG10
(ZPA = 1,00 g)
4.3 Selection of seismic qualification level
4.3.1 General
The project-specific seismic qualification level is selected taking into account the site-specific
seismic hazard level described in 4.3.2, the effect of building response and elevation described
in 4.3.3 and additional factors such as soil-structure
...