IEC TS 62271-304:2019
(Main)High-voltage switchgear and controlgear - Part 304: Classification of indoor enclosed switchgear and controlgear for rated voltages above 1 kV up to and including 52 kV related to the use in special service conditions with respect to condensation and pollution
High-voltage switchgear and controlgear - Part 304: Classification of indoor enclosed switchgear and controlgear for rated voltages above 1 kV up to and including 52 kV related to the use in special service conditions with respect to condensation and pollution
IEC TS 62271-304:2019 applies to indoor enclosed switchgear and controlgear complying with IEC 62271-200 and IEC 62271-201, intended to be used in special service conditions with respect to condensation and pollution deviating from the normal service conditions specified in IEC 62271-1.
The test detailed in this document has been designed primarily to classify the electrical insulation performance of equipment having high-voltage electrical insulation exposed to indoor service conditions, mainly in presence of condensation. The assessment of mechanical components, such as mechanisms, interlocks and enclosure is also considered.
This second edition cancels and replaces the first edition published in 2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the description of the several service conditions under condensation and pollution;
b) the classification of enclosed switchgear and controlgear, according to the testing procedure does not cover polluted service conditions PL and PH;
c) a wider description in Annex B of typical indoor environments based on ISO/IEC standards;
d) a new Annex C giving guidance on precautions to improve indoor operating conditions;
e) a new Annex D dedicated to the optional items such as records of mechanical characteristics;
f) a new Annex E, giving additional combinations of environments with condensation and pollution, as well as a proposal of testing procedure of ageing test, is provided to create experience on correlation between ageing effects in laboratory and ageing effects at site conditions.
Appareillage à haute tension - Partie 304: Classification de l’appareillage d’intérieur sous enveloppe pour tensions assignées supérieures à 1 kV et jusqu’à 52 kV inclus relatives à l’utilisation dans des conditions spéciales de service en ce qui concerne la condensation et la pollution
L’IEC TS 62271-304:2019 s’applique à l’appareillage d’intérieur sous enveloppe conforme à l’IEC 62271-200 et à l’IEC 62271-201, destiné à être utilisé dans des conditions spéciales de service en ce qui concerne la condensation et la pollution s’écartant des conditions normales de service spécifiées dans l’IEC 62271-1.
Les essais faisant l’objet du présent document ont été principalement conçus pour classifier les performances d’isolation électrique des appareillages ayant une isolation électrique haute tension exposée aux conditions de service d’intérieur, notamment en présence de condensation. L’évaluation des composants mécaniques tels que les mécanismes, les verrouillages et l’enveloppe est également considérée.
Cette deuxième édition annule et remplace la première édition parue en 2008. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
a) la description des différentes conditions de service sous condensation et pollution;
b) la classification de l’appareillage sous enveloppe, conformément à la procédure d’essai, ne couvre pas les conditions de service avec pollution PL et PH;
c) une description plus complète à l'Annexe B des environnements d’intérieur typiques basés sur des normes ISO/IEC;
d) une nouvelle Annexe C donnant des recommandations relatives aux précautions pour améliorer les conditions d’exploitation intérieures;
e) une nouvelle Annexe D fournissant les éléments facultatifs comme les enregistrements des caractéristiques mécaniques;
f) une nouvelle Annexe E offrant des combinaisons d’environnements supplémentaires avec condensation et pollution, ainsi qu’une proposition de procédure d’essai de vieillissement, afin de créer de l’expérience sur la corrélation entre les effets du vieillissement en laboratoire et les effets du vieillissement dans les conditions de site.
General Information
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Standards Content (Sample)
IEC TS 62271-304 ®
Edition 2.0 2019-03
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
High-voltage switchgear and controlgear –
Part 304: Classification of indoor enclosed switchgear and controlgear for rated
voltages above 1 kV up to and including 52 kV related to the use in special
service conditions with respect to condensation and pollution
Appareillage à haute tension –
Partie 304: Classification de l’appareillage d’intérieur sous enveloppe pour
tensions assignées supérieures à 1 kV et jusqu’à 52 kV inclus relatives à
l’utilisation dans des conditions spéciales de service en ce qui concerne la
condensation et la pollution
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IEC TS 62271-304 ®
Edition 2.0 2019-03
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
High-voltage switchgear and controlgear –
Part 304: Classification of indoor enclosed switchgear and controlgear for rated
voltages above 1 kV up to and including 52 kV related to the use in special
service conditions with respect to condensation and pollution
Appareillage à haute tension –
Partie 304: Classification de l’appareillage d’intérieur sous enveloppe pour
tensions assignées supérieures à 1 kV et jusqu’à 52 kV inclus relatives à
l’utilisation dans des conditions spéciales de service en ce qui concerne la
condensation et la pollution
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.10 ISBN 978-2-8322-6674-8
– 2 – IEC TS 62271-304:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Definition of indoor service conditions under condensation and pollution . 7
5 Classification of enclosed switchgear and controlgear . 8
6 Test procedure for classification . 8
7 Test facilities and associated requirements . 10
7.1 Climatic test room . 10
7.2 Measurement and control requirements . 10
7.3 Energizing facilities . 10
7.4 Information to be included in the test report . 10
8 Arrangement of the equipment for test . 11
9 Ageing test . 11
9.1 Level 1 ageing test . 11
9.2 Level 2 ageing test . 12
10 Electrical assessment after ageing test . 13
10.1 General . 13
10.2 Criteria to pass the tests . 14
Annex A (informative) Climatic test room . 15
Annex B (informative) Typical indoor environments . 16
B.1 General . 16
B.2 Pollution . 16
Annex C (informative) Typical precautions to improve indoor operating conditions . 20
C.1 General . 20
C.2 Precautions for operating room . 20
Annex D (informative) Mechanical assessment . 21
Annex E (informative) Pollution testing conditions, parameters, and procedure . 22
E.1 General . 22
E.2 Proposal for new classes . 22
E.3 Testing procedure . 22
E.3.1 Testing conditions . 22
E.3.2 Testing parameters . 23
E.3.3 Testing procedure . 23
Bibliography . 26
Figure 1 – Flow chart for classification testing procedure . 9
Figure 2 – Climatic conditions for ageing test for level 1 and electrical assessment . 12
Figure 3 – Power-frequency voltage test sequences with high humidity after ageing
test . 14
Figure A.1 – Climatic test room . 15
Figure E.1 – Test cycle . 24
Table B.1 – Examples of typical environments (IEC TS 60815-1, IEC 60721-3-3) . 17
Table B.2 – Concentrations of some of the most important pollutants in different types
of environments (Annex B of ISO 9223:2012 [8], IEC 60721-3-3) . 18
Table B.3 – Deposits of some of the most important pollutants in different types of
environments (Annex B of ISO 9223:2012 [8], IEC TS 60815-1, IEC 60721-3-3,
IEC 60721-2-5[7]) . 19
Table C.1 – Typical precautions to improve indoor operating conditions . 20
– 4 – IEC TS 62271-304:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 304: Classification of indoor enclosed switchgear and controlgear for
rated voltages above 1 kV up to and including 52 kV related to the use in
special service conditions with respect to condensation and pollution
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
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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
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
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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
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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. In
exceptional circumstances, a technical committee may propose the publication of a Technical
Specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical Specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62771-304, which is a Technical Specification, has been prepared by subcommittee 17C:
Assemblies, of IEC technical committee 17: High-voltage switchgear and controlgear.
This second edition cancels and replaces the first edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the description of the several service conditions under condensation and pollution;
b) the classification of enclosed switchgear and controlgear, according to the testing
procedure does not cover polluted service conditions P and P ;
L H
c) a wider description in Annex B of typical indoor environments based on ISO/IEC
standards;
d) a new Annex C giving guidance on precautions to improve indoor operating conditions;
e) a new Annex D dedicated to the optional items such as records of mechanical
characteristics;
f) a new Annex E, giving additional combinations of environments with condensation and
pollution, as well as a proposal of testing procedure of ageing test, is provided to create
experience on correlation between ageing effects in laboratory and ageing effects at site
conditions.
The text of this Technical Specification is based on the following documents:
Draft TS Report on voting
17C/679/DTS 17C/691/RVDTS
Full information on the voting for the approval of this Technical Specification can be found in
the report on voting indicated in the above table.
This document 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 document will remain unchanged until the
stability date indicated on the IEC website under "http://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 publication 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.
– 6 – IEC TS 62271-304:2019 © IEC 2019
HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 304: Classification of indoor enclosed switchgear and controlgear for
rated voltages above 1 kV up to and including 52 kV related to the use in
special service conditions with respect to condensation and pollution
1 Scope
This part of IEC 62271, which is a Technical Specification, applies to indoor enclosed
switchgear and controlgear complying with IEC 62271-200 and IEC 62271-201, intended to be
used in special service conditions with respect to condensation and pollution deviating from
the normal service conditions specified in IEC 62271-1.
The test detailed in this document has been designed primarily to classify the electrical
insulation performance of equipment having high-voltage electrical insulation exposed to
indoor service conditions, mainly in presence of condensation. The assessment of mechanical
components, such as mechanisms, interlocks and enclosure is also considered.
In this document, the term "equipment" is used in accordance with the scope for an "enclosed
assembly of switchgear and controlgear" (see IEC 60050-441:2000, 441-12- 02).
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 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60721-3-3, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 3: Stationary use at weatherprotected
locations
IEC TS 60815-1, Selection and dimensioning of high-voltage insulators intended for use in
polluted conditions – Part 1: Definitions, information and general principles
IEC 62271-1:2017, High-voltage switchgear and controlgear – Part 1: Common specifications
for alternating current switchgear and controlgear
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
IEC 62271-201, 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
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62271-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Definition of indoor service conditions under condensation and pollution
Indoor equipment is designed to be installed in an operating room inside a building or other
housing and thus has a certain level of protection from the outdoor environmental conditions.
In addition of the protection given by the building or other housing construction, precautions
(see Annex C) to minimize the amount of deposits inside the switchgear and controlgear can
be taken by the choice of an appropriate degree of protection of the enclosed switchgear and
controlgear.
Condensation can occur due to rapid temperature changes inside the operating room.
Pollution inside the operating room can be present depending on location and surrounding
activity. In addition, the occurrence of condensation and the site pollution severity inside the
operating room depend on the layout and the protection given by the building or other housing
construction.
The presence of condensation and pollution has the potential to impact the voltage withstand
capability of clearances and creepage distances, and possibly the insulating material itself.
The concern is that there may be the creation of a full or partial conductive path between live
parts or between live parts and conductive parts not intended to be live (enclosure, etc.).
In this document, the indoor service conditions with respect to condensation and pollution
around the enclosed switchgear and controlgear are defined, with typical examples:
: Condensation does not normally occur (not more than twice a year)
C
• Rooms with continuous humidity and/or temperature control in order to avoid
condensation. The building or other housing provides protection from daily
variations in outside climate.
• Rooms not having humidity or temperature control. Nevertheless, the building or
other housing construction provides protection from daily variations in outside
climate, and condensation is not more than twice a year.
C : Non-frequent condensation (not more than twice a month)
L
• Rooms not having humidity or temperature control. The building or other housing
construction provides protection from daily variations in outside climate, but
condensation cannot be excluded.
C : Frequent condensation (more than twice a month)
H
• Rooms not having humidity nor temperature control. The building or other housing
provides only minimal protection from daily variations of outside climate, so that
frequent condensation may occur.
P : Very light pollution (as given in 4.1.2, item d), of IEC 62271-1:2017). The ambient air
of the operating room is not significantly polluted by dust, smoke, corrosive and/or
flammable gases, vapours or salt and would be considered as having site pollution
severity class (SPS) “very light” according to IEC TS 60815-1.
• Rooms in areas without significant pollution.
– 8 – IEC TS 62271-304:2019 © IEC 2019
• Rooms in areas with pollution (see Annex B) with precautions against pollution (see
Annex C) to recover indoor normal service conditions.
• Rooms with precautions against pollution (see Annex C). The building or other
housing construction provides adapted protection from outside pollution. The
control of the air conditions may be switched off for periods.
P : Light pollution is considered as site pollution severity class (SPS) “light” according to
L
IEC TS 60815-1 for solid deposit and/or pollution classification 3C1 according to
IEC 60721-3-3.
• Rooms without precautions against pollution. The building or other housing
construction is exposed to ambient air in rural and some urban areas with industrial
activities or with moderate traffic.
P : Heavy pollution (any pollution level exceeding P )
H L
• Rooms without precautions against pollution. The building or other housing
construction is exposed to ambient air in urban areas with industrial activities or
with heavy traffic.
5 Classification of enclosed switchgear and controlgear
Classification of enclosed switchgear and controlgear for use in special service conditions
with respect to condensation, within this document, is limited to equipment intended for use in
a polluted environment classified as P . The available classes are:
Class 0: C P
0 0
Class 1: C P
L 0
Class 2: C P
H 0
Test procedures are defined to demonstrate conformance with the requirements of C and C .
L H
Class 0 corresponds to normal indoor service conditions defined in IEC 62271-1.
Most of the existing artificial pollution testing procedures [2] [3] [4] [5] are mainly dedicated
to glass, ceramic, and polymeric insulators exposed to outdoor service conditions. There is no
mature testing methodology, representative of ageing under polluted indoor service
conditions. Therefore, no testing procedure is provided in this document for polluted
environments P and P .
L H
However, Annex E gives other possible combinations of environments with condensation and
pollution, and a proposal for testing procedure of ageing test, in order to create experience on
correlation between ageing effects in laboratory and ageing effects at site conditions.
Pollution at the site should be recorded.
6 Test procedure for classification
Class 0 is considered to be equivalent to the indoor normal service conditions specified in
IEC 62271-1, therefore no test is required.
Satisfactory performance under special service conditions of equipment complying with
Class 1 or 2 is verified by testing the equipment.
Enclosed switchgear and controlgear is considered to belong to Class 1 if it is subjected to
the level 1 ageing test according to 9.1 and satisfies the criteria of the electrical assessment.
Optional mechanical assessment is described in Annex D.
—————————
Numbers in square brackets refer to the Bibliography.
Enclosed switchgear and controlgear is considered to belong to Class 2 if it is submitted to
the level 2 ageing test according to 9.2 and satisfies the criteria of the electrical assessment.
Optional mechanical assessment is described in Annex D.
The level 1 and level 2 ageing tests require the repeated application of identical cycles
followed by the electrical assessment. Optional mechanical assessment is described in
Annex D. The level 2 ageing test is identical to the level 1 ageing test except that for level 2 a
larger number of cycles is to be applied.
This classification procedure is illustrated in the flow chart, Figure 1.
Figure 1 – Flow chart for classification testing procedure
– 10 – IEC TS 62271-304:2019 © IEC 2019
7 Test facilities and associated requirements
7.1 Climatic test room
A climatic test room is required which shall be of sufficient size to accommodate the
equipment to be tested. The equipment shall be installed in the climatic test room at a height
of not less than 0,5 m from the ground in a manner to permit the circulation of the ambient air.
The clearance between the walls and ceiling of the test room and the test object shall be more
than 1,0 m. When this requirement cannot be met, the laboratory shall provide evidence that
the ambient conditions meet the requirements according to 7.2.
Precautions shall be taken to prevent condensed water on the walls and ceiling of the test
chamber from falling on the equipment.
The distribution of temperature and humidity in the whole volume of the chamber is assumed
to be homogenous when the clearance is more than 1 m. Annex A provides a figure
illustrating the arrangement of a test object inside a climatic test room.
Water utilized to maintain humidity shall have an electrical conductivity of not more
than 20 µS/cm.
NOTE The value of water conductivity comes from IEC 60068-2-78 [6].
7.2 Measurement and control requirements
The air temperature control system of the test chamber shall be able to keep the required
temperatures with a tolerance of ±3 K. During the tests, it shall be varied cyclically
between 30 °C and 50 °C. The temperature gradient shall be at least 0,5 K/min.
The relative humidity shall be controlled to be within the specified limits given in Clause 9.
Where the clearance defined in 7.1, between the test room and the test object is not met, the
laboratory shall verify the temperature and humidity surrounding the test object at the middle
of the concerned clearances.
7.3 Energizing facilities
A three-phase high-voltage source, star connection with neutral connected to earth, shall be
provided to energize the equipment during the ageing test. This source shall be able to
maintain the rated voltage of the equipment with a tolerance of 0 % to –5 % during the ageing
cycles. The voltage shall be monitored continuously during the full duration of the tests to
detect possible disruptive discharge.
A source is required for applying test voltages up to at least the dry power-frequency
withstand voltage of the equipment to be tested. This source shall comply with IEC 60060-1.
Each source shall have a protective device operating in less than 0,1 s in the event of a
disruptive discharge.
7.4 Information to be included in the test report
The results of the tests shall be recorded in the test report, which shall contain sufficient data
to fully identify and describe the test object in terms of its essential parts and its ratings, as
specified in the relevant indoor enclosed switchgear standard. In particular, the following
information shall be included:
• manufacturer;
• type designation and serial number of the test object;
• rated characteristics of the test object as specified in the relevant IEC standard;
• general description of the test object, including number of poles;
• manufacturer, type, serial numbers and ratings of essential parts, where applicable (for
example, drive mechanisms, interrupters, shunt impedances);
• general details of the supporting structure of the enclosed switchgear;
• details of the operating-mechanism and devices employed during tests, where applicable;
• photographs to illustrate the condition of the test object before and after the test;
• sufficient outline drawings and data schedules to represent the test object;
• reference numbers of all drawings including the revision number submitted to identify the
essential parts of the test object;
• statement that the test object complies with the drawings submitted;
• details of the testing arrangements (including diagram of the test circuit);
• statements of the behaviour of the test object during tests, and its condition after tests;
• records of the test quantities during each test as specified in this document;
• conductivity of water used;
• location, laboratory name where the tests were conducted and date of test.
8 Arrangement of the equipment for test
The ageing test shall be made on the equipment completely assembled and fitted with all its
components as for service, instrument transformers included. The equipment and its
components shall be new and clean.
The equipment to be tested shall be installed in the climatic test room and connected as in
service, in its normal operating position and normal installation condition. The frame and other
parts of the equipment intended to be earthed in service shall be earthed for testing.
The representative floor of the test installation conditions and/or bottom plates (if used) of the
switchgear and controlgear shall be used and described within the test report.
9 Ageing test
9.1 Level 1 ageing test
The equipment shall be installed in the climatic test room and subjected during three identical
test periods of seven days (see Figure 2), to 2 h damp heat cycles described by zones as
follows:
Zone 1: to rise from 30 °C to 50 °C within 40 min, with the relative humidity above 95 %.
Zone 2: to maintain 50°C during 20 min with the relative humidity above 95 %.
Zone 3: to decrease from 50°C to 30 °C within 40 min, with any convenient value of
humidity.
Zone 4: to maintain 30 °C during 20 min, with the relative humidity above 80 %.
The test period of seven days duration is made up as follows:
For five days, the equipment to be tested is energized at its rated voltage and subjected to
60 damp heat cycles as described above. The application of rated voltage means U
r
between phases and U / 3 between phase and earth.
r
After these five days the test is stopped at the end of the last cycle at 30 °C. The
equipment is de-energized.
– 12 – IEC TS 62271-304:2019 © IEC 2019
For two days, the equipment shall be maintained in an atmosphere close to the reference
atmosphere mentioned in IEC 60060-1, i.e. with temperature at 20°C and relative humidity
60 % approximately.
After the completion of three test periods, the performance of the equipment shall be
evaluated in accordance with the electrical assessment. The optional mechanical assessment
is described in Annex D.
21 days
0 to 3 days
5 days 2 days ≤1 h
3 h
T (°C)
2 h
53°C
47°C
33°C
27°C
20°C
Relative humidity
%
504 h
1 h 2 h 120 h 168 h t (h)
Energized Energized
Power-
frequency
voltage test at
De-energized
(Dry) Power-frequency high humidity
voltage test (see Figure 3)
Ageing test Electrical assessment
IEC
Figure 2 – Climatic conditions for ageing test for level 1 and electrical assessment
9.2 Level 2 ageing test
The level 2 ageing test comprises a total of seven identical test periods of seven days, as
defined in 9.1, followed by the electrical assessment. The optional mechanical assessment is
described in Annex D.
If the test object has already been successfully subjected to the level 1 ageing test, it is
permitted to continue the test immediately after the electrical assessment, applying four
additional test periods of seven days.
Relative humidity uncontrolled
Relative humidity uncontrolled
Relative humidity uncontrolled
10 Electrical assessment after ageing test
10.1 General
After the conclusion of the ageing tests, and reaching ambient temperature, the equipment
shall be subjected to dielectric tests as follows without any special treatment like cleaning,
extra drying, etc. The voltage transformers shall be disconnected before the electrical
assessment. The overvoltage protective devices may be disconnected or removed before
electrical assessment.
The equipment with the main switching device(s) in closed position if any, is first subjected to
the dry 1 min power-frequency withstand voltage test at its rated value according to
IEC 62271-1.
After the dry power-frequency test, it is permissible to maintain the same ambient conditions
for a maximum of 3 days before continuing the electrical assessment.
The voltage shall be removed and the temperature in the climatic test room shall be increased
to 30 °C and the humidity at least to 95 % in less than 1 h. After 3 h in these conditions, the
following dielectric test is performed (see Figure 3).
One phase is energized at U / 3 with a tolerance of ±3 %, where U is the rated voltage of
r r
the equipment, the other two phases being earthed.
After 1 h, the voltage is raised to 3 U with a tolerance of ±1 %, and maintained during 30 s
r
(voltage rise in accordance with 6.3.1 of IEC 60060-1:2010).
The voltage test sequence is repeated successively on the other two phases. If each phase is
fully separated from the others by earthed partitions or fully surrounded by earthed screens,
the three phases may be energized together.
Photos of the test object shall be included in the test report, showing traces of tracking on
insulating surfaces, if any.
– 14 – IEC TS 62271-304:2019 © IEC 2019
Figure 3 – Power-frequency voltage test sequences
with high humidity after ageing test
10.2 Criteria to pass the tests
The equipment complies with Class 1 or 2 if the following conditions are satisfied:
• no disruptive discharge has occurred during the cycles according to the ageing test;
• no disruptive discharge has occurred during the electrical assessment.
Annex A
(informative)
Climatic test room
The test object should be placed in the test room with a clearance respectively to the walls
and to any shapes of the ceiling or bottom part of the roof as shown in Figure A.1.
Figure A.1 – Climatic test room
– 16 – IEC TS 62271-304:2019 © IEC 2019
Annex B
(informative)
Typical indoor environments
B.1 General
This annex provides guidance for the user to determine the service conditions with respect to
condensation and pollution in an operating room where the switchgear and controlgear is
intended to be installed.
Condensation occurs under certain combinations of conditions concerning temperature
change and relative humidity. This is valid for the switchgear and controlgear parts and also
for the operating room inside a building or other housing.
Only condensation which could generate presence of liquid water on the switchgear and
controlgear component should be considered as follows:
– direct condensation on switchgear and controlgear parts;
– fall of droplets on switchgear and controlgear surfaces.
In addition to the environmental parameters already defined by IEC 60721-3-3, the
condensation is influenced by other different parameters as follows:
• thermal capacity of the switchgear and controlgear parts;
• distribution of the ambient temperature inside the operating room;
• cable penetration tightness;
• design features of the housing such as openings, door frame, louvers, material of the
housing;
• active control of humidity and temperature;
• electrical load;
• humid soil conditions.
To determine the ambient conditions of the operating room, measurement by permanent
monitoring or specific study considering applicable influence factors (see Annex C) should be
carried out.
B.2 Pollution
Pollution inside the operating room depends on outside environmental conditions and
pollution activity, and the room itself (see Table B.1). Two main kinds of pollution should be
considered:
– gaseous pollutants
– solid deposits that are non-conductive in dry condition.
Concentrations of gaseous pollutants are defined in IEC 60721-3-3 and displayed in Table
B.2. Densities or rates of solid deposits are listed in Table B.3.
Solid deposit rate may be evaluated in accordance with IEC TS 60815-1.
Any assessment of the pollution values should be carried out inside operating room. The
values provided in Tables B.2 and B.3 are applicable to weather protected locations.
Table B.1 – Examples of typical environments (IEC TS 60815-1, IEC 60721-3-3)
Building or other housing exposed to pollution
Rooms without significant pollution or with pollution control which may be switched
“Very
P 3C1L off for periods. The building or other housing construction provides adapted
light”
protection from outside pollution
Rooms without precautions against pollution. The building or other housing
P “Light” 3C1 construction is exposed to ambient air in rural and some urban areas with
L
industrial activities or with moderate traffic.
“Medium”
3C2
“Heavy” Rooms without precautions against pollution. The building or other housing
P 3C3
H
construction is exposed to polluted ambient air.
“Very
3C4
heavy”
For pollution levels higher than P the classifications C P and C P cannot be assessed
0 x L x H
since there is no dedicated test covering the whole scope of pollutants to classify the
switchgear and controlgear. There is no unique pollutant reflecting a right classification by
test procedure as previously done by IEC TR 60932 using salt fog. In addition, certain
pollutants cannot be introduced during the test procedure due to the facilities of laboratories.
However, Annex E investigates a proposal for a new testing procedure of ageing test where
the effect of pollutant is reproduced by a proposal of a range of water conductivity to gain
experience on correlation between ageing effects in laboratory and ageing effects at site
conditions. Pollution at site should be recorded.
The highest frequency of condensation combined with the highest severity of pollution i.e.
P should not be specified for indoor equipment where any of the high-voltage insulation is
C
H H
exposed to ambient conditions, without special precautions (see Annex C).
When the pollution severity is higher than P , precautions should be taken to not expose
insulating part(s) to the indoor service conditions or improve the operating room to reduce the
severities P and P to recover a level of pollution at P (see Annex C).
L H 0
Pollution levels of the operating
room
IEC TS 60815-1
SPS severity classes
IEC 60721-3-3
Chemically active classifications
– 18 – IEC TS 62271-304:2019 © IEC 2019
Table B.2 – Concentrations of some of the most important pollutants in different types
of environments (Annex B of ISO 9223:2012 [8], IEC 60721-3-3)
Pollutant ISO 9223 IEC 60721-3-3 ISO 9223 ISO 9223
Concentration Source of pollutant
/deposition Reference
value
Class Area
(annual
average value)
(µg/m )
(µg/m )
2 – 15 10 rural
The main sources for SO are the use
3C1L
SO 5 – 100 100 max urban of coal and oil and emissions from
3C1
industrial plants.
50 – 400 300 3C2 industrial
2 – 25 3C1L rural
Traffic is the main source for NO
NO 100 max
emissions.
20 – 150 3C1 urban
0,1 – 0,7 rural
HNO is correlated with NO . High
3 2
concentrations of NO , organic
HNO
urban
compounds and UV light increase the
0,5 – 4
concentration.
Industrial
3C1L
O is formed in the atmosphere by
< 10 10 max 3
3C1
interactions among sunlight, oxygen
O and pollutants. The concentrati
...
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