IEC 60871-1:2014

Shunt capacitors for a.c. power systems having a rated voltage above 1 000 V - Part 1: General

IEC 60871-1:2014 is applicable to both capacitor units and capacitor banks intended to be used, particularly, for power-factor correction of a.c. power systems having a rated voltage above 1 000 V and frequencies of 15 Hz to 60 Hz. This part of IEC 60871 also applies to capacitors intended for use in power filter circuits. The object of this part of IEC 60871 is as follows:
- to formulate uniform rules regarding the performance and rating of units and banks, and the testing of units; to formulate specific safety rules;
- to provide a guide for installation and operation. This fourth edition cancels and replaces the third edition published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- the overvoltage cycling test has been moved to this standard from the IEC 60871-2;
- the ranges of the standardized values of the highest voltage for equipment have been modified;
- for installations installed on altitudes above 1 000 m a correction factor to all insulation requirements has been introduced;
- new standard insulation tables have been defined. Keywords: capacitor units and capacitor banks, power filter circuits

Condensateurs shunt pour réseaux à courant alternatif de tension assignée supérieure à 1 000 V - Partie 1: Généralités

L'IEC 60871-1:2014 est applicable aux condensateurs unitaires et aux batteries de condensateurs destinés plus particulièrement à la correction du facteur de puissance des réseaux à courant alternatif de tension assignée supérieure à 1 000 V et de fréquence comprise entre 15 Hz et 60 Hz. Cette partie de l'IEC 60871 est également applicable aux condensateurs destinés à être utilisés pour le filtrage dans les circuits de puissance. La présente partie de l'IEC 60871 a pour objet:
- de formuler des règles uniformes pour les performances et les caractéristiques assignées des condensateurs et des batteries, et pour les essais des condensateurs unitaires;
- de formuler des règles spécifiques de sécurité;
- de servir de guide d'installation et d'exploitation. Cette quatrième édition annule et remplace la troisième édition parue en 2005. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- l'essai de tenue aux surtensions a été supprimé de l'IEC 60871-2 et intégré dans la présente norme;
- les plages des valeurs normalisées de la tension la plus élevée pour le matériel ont été modifiées;
- pour les installations situées à des altitudes supérieures à 1 000 m, un facteur de correction à toutes les exigences d'isolation a été introduit;
- de nouveaux tableaux d'isolement normalisé ont été définis. Mots clés: condensateurs unitaires et aux batteries de condensateurs, filtrage dans les circuits de puissance

General Information

• Status: Published
• Publication Date: 21-May-2014
• ICS: 29.240.99 - Other equipment related to power transmission and distribution networks
• ICS: 31.060.70 - Power capacitors
• Technical Committee: TC 33 - Power capacitors and their applications
• Drafting Committee: MT 19 - TC 33/MT 19
• Current Stage: PPUB - Publication issued
• Start Date: 22-May-2014
• Completion Date: 15-Jun-2014

Relations

• Revises: IEC 60871-1:2005 - Shunt capacitors for a.c. power systems having a rated voltage above 1000 V - Part 1: General
• Effective Date: 05-Sep-2023

Overview

IEC 60871-1:2014 is an international standard published by the International Electrotechnical Commission (IEC) focusing on shunt capacitors used in an alternating current (a.c.) power system with rated voltages above 1,000 volts. This seventh edition supersedes the 2005 version, introducing technical revisions addressing overvoltage cycling tests, insulation requirements for high-altitude installations, and updated standardized voltage values.

This standard covers both individual capacitor units and capacitor banks, which are predominantly utilized for power-factor correction and in power filter circuits within electrical networks operating at frequencies from 15 Hz to 60 Hz. It aims to standardize performance, rating, and testing procedures, while also providing safety requirements and installation guidance.

Key Topics

• Scope and Application
  Applicable for shunt capacitors in a.c. power systems with voltage ratings above 1,000 V and frequencies between 15 Hz and 60 Hz. Includes power filter circuit capacitors as well.

• Performance and Safety Rules
  Establishes uniform criteria for capacitor unit and bank performance, testing protocols (routine, type, acceptance), and comprehensive safety measures related to discharge devices and container connections.

• Testing Procedures
  Key tests specified include capacitance measurement, loss angle (tan δ) evaluation, voltage tests (AC, DC, and lightning impulse), sealing and thermal stability testing, overvoltage cycling, short-circuit discharge, and insulation level assessments.

• Insulation and Overvoltage Standards
  Defines insulation levels and introduces correction factors for installations above 1,000 m altitude. Standards for maximum permissible voltage and currents-both continuous and transient-are detailed.

• Installation and Operation Guidance
  Offers practical instructions for selecting rated voltage, managing operating temperature and unusual service conditions, dealing with overvoltages (lightning, switching transient phenomena), and safeguards involving switching and protective devices.

• Markings and Documentation
  Specifies requirements for rating and warning plates on capacitor units and banks, including standardized connection symbols, facilitating correct installation and maintenance.

Applications

IEC 60871-1:2014 is critically important for:

• Power-Factor Correction Installations
  Ensuring efficient operation of capacitor banks that manage reactive power to improve the power factor of electrical systems, leading to energy savings and reduced losses in transmission.

• Power Filter Circuits
  Guiding the design and use of capacitors in harmonic filtering applications to maintain power quality and system reliability.

• High-Voltage Industrial Systems
  Offering specifications for capacitors used in large-scale industrial and utility-scale power systems where voltage ratings exceed 1 kV.

• Environmental and Safety Compliance
  Assisting manufacturers and engineers in meeting international safety standards, environmental protection measures, and reliable capacitor operation under various service conditions including harsh and elevated altitude environments.

Related Standards

• IEC 60871-2: Covers capacitor units designed for different voltage ranges and specific tests not included in Part 1, particularly focusing on metallized film capacitors.

• IEC 61071: General standards on power capacitors which may detail design and application considerations complementing IEC 60871-1.

• IEC 60071: Insulation coordination for power systems offers foundational guidance relevant to setting insulation levels for capacitors.

By aligning with IEC 60871-1:2014, engineers, manufacturers, and system operators ensure consistency, safety, and efficiency in deploying shunt capacitors within high-voltage a.c. power networks, supporting global electrification and sustainable power management goals.

Standards Content (Sample)

IEC 60871-1 ®
Edition 4.0 2014-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Shunt capacitors for a.c. power systems having a rated voltage above 1 000 V –
Part 1: General
Condensateurs shunt pour réseaux à courant alternatif de tension assignée
supérieure à 1 000 V –
Partie 1: Généralités
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IEC 60871-1 ®
Edition 4.0 2014-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Shunt capacitors for a.c. power systems having a rated voltage above 1 000 V –

Part 1: General
Condensateurs shunt pour réseaux à courant alternatif de tension assignée

supérieure à 1 000 V –
Partie 1: Généralités
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XA
ICS 29.240.99; 31.060.70 ISBN 978-2-8322-1580-7

– 2 – IEC 60871-1:2014 © IEC 2014
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 9
3 Terms and definitions . 9
4 Service conditions . 12
4.1 Normal service conditions . 12
4.2 Unusual service conditions . 13
5 Quality requirements and tests . 13
5.1 General . 13
5.2 Test conditions . 13
6 Classification of tests. 13
6.1 General . 13
6.2 Routine tests. 13
6.3 Type tests . 14
6.4 Acceptance tests . 14
6.5 Endurance test (special test) . 14
7 Capacitance measurement (routine test). 14
7.1 Measuring procedure . 14
7.2 Capacitance tolerances . 15
8 Measurement of the tangent of the loss angle (tan δ) of the capacitor (routine test) . 15
8.1 Measuring procedure . 15
8.2 Loss requirements . 16
8.3 Losses in external fuses . 16
9 Voltage test between terminals (routine test) . 16
9.1 General . 16
9.2 AC test . 16
9.3 DC test . 16
10 AC voltage test between terminals and container (routine test) . 16
11 Test of internal discharge device (routine test) . 17
12 Sealing test (routine test) . 17
13 Thermal stability test (type test) . 17
13.1 General . 17
13.2 Measuring procedure . 17
14 Measurement of the tangent of the loss angle (tan δ) of the capacitor at elevated
temperature (type test) . 18
14.1 Measuring procedure . 18
14.2 Requirements . 18
15 Voltage tests between terminals and container (type tests) . 19
15.1 AC voltage test between terminals and container . 19
15.2 Lightning impulse test between terminals and container . 19
16 Overvoltage test (type test) . 20
16.1 General . 20
16.2 Conditioning of the sample before the test . 20
16.3 Test procedure . 20

16.4 Acceptance criteria . 21
16.5 Validity of test . 21
16.5.1 General . 21
16.5.2 Element design . 21
16.5.3 Test unit design . 21
16.5.4 Waveform of overvoltage . 21
17 Short-circuit discharge test (type test) . 22
18 Insulation levels . 22
18.1 Standard insulation values . 22
18.2 General requirements . 23
18.2.1 General . 23
18.2.2 Adjacent insulating components and equipment . 23
18.2.3 Capacitors insulated from ground . 23
18.2.4 Capacitors with neutral connected to ground . 23
18.3 Test between terminals and container of capacitor units . 24
18.4 Capacitors in single-phase systems . 24
19 Overloads – Maximum permissible voltage . 27
19.1 Long duration voltages . 27
19.2 Switching overvoltages . 27
20 Overloads – Maximum permissible current. 27
21 Safety requirements for discharge devices . 28
22 Safety requirements for container connections . 28
23 Safety requirements for protection of the environment . 28
24 Other safety requirements . 28
25 Markings of the capacitor unit . 29
25.1 Rating plate . 29
25.2 Standardized connection symbols . 29
25.3 Warning plate . 29
26 Markings of the capacitor bank . 30
26.1 Instruction sheet or rating plate . 30
26.2 Warning plate . 30
27 Guide for installation and operation . 30
27.1 General . 30
27.2 Choice of the rated voltage . 30
27.3 Operating temperature . 31
27.3.1 General . 31
27.3.2 Installation . 31
27.3.3 High ambient air temperature. 32
27.4 Special service conditions . 32
27.5 Overvoltages . 32
27.5.1 General . 32
27.5.2 Restriking of switches . 33
27.5.3 Lightning . 33
27.5.4 Motor self-excitation . 33
27.5.5 Star-delta starting . 33
27.5.6 Capacitor unit selection . 33
27.6 Overload currents . 33

– 4 – IEC 60871-1:2014 © IEC 2014
27.6.1 Continuous overcurrents . 33
27.6.2 Transient overcurrents . 34
27.7 Switching and protective devices . 34
27.7.1 Withstand requirements . 34
27.7.2 Restrike-free circuit-breakers . 35
27.7.3 Relay settings . 35
27.8 Choice of insulation levels . 36
27.8.1 General . 36
27.8.2 Altitudes exceeding 1 000 m . 36
27.8.3 Influence of the capacitor itself . 36
27.8.4 Overhead ground wires . 38
27.9 Choice of creepage distances and air clearance . 38
27.9.1 Creepage distance . 38
27.9.2 Air clearances. 39
27.10 Capacitors connected to systems with audio-frequency remote control . 41
Annex A (normative) Precautions to be taken to avoid pollution of the environment by
polychlorinated biphenyls . 42
Annex B (normative) Additional definitions, requirements and tests for power filter
capacitors . 43
Annex C (normative) Test requirements and application guide for external fuses and
units to be externally fused . 45
C.1 General . 45
C.2 Terms and definitions . 45
C.3 Performance requirements . 45
C.4 Tests . 45
C.4.1 Tests on fuses . 45
C.4.2 Type tests on capacitor containers . 45
C.5 Guide for coordination of fuse protection . 46
C.5.1 General . 46
C.5.2 Protection sequence . 46
C.6 Choice of fuses . 46
C.6.1 General . 46
C.6.2 Non current-limiting fuses . 47
C.6.3 Current-limiting fuses. 47
C.7 Information needed by the user of the fuses . 47
Annex D (informative) Formulae for capacitors and installations . 48
D.1 Computation of the output of three-phase capacitors from three single-phase
capacitance measurements . 48
D.2 Resonant frequency . 48
D.3 Voltage increase . 48
D.4 Inrush transient current . 49
D.4.1 Switching in of single capacitor bank . 49
D.4.2 Switching on of a bank in parallel with energized bank(s) . 49
D.5 Discharge resistance in single-phase unit . 49
D.6 Discharge time to 10 % of rated voltage . 49
Annex E (informative) Capacitor bank fusing and unit arrangement. 51
E.1 General . 51
E.2 Internally fused capacitor bank . 51
E.3 Externally fused capacitor bank . 51

E.4 Fuseless capacitor bank . 51
Bibliography . 54

Figure 1 – Time and amplitude limits for an overvoltage period . 22
Figure 2 – Bank isolated from ground . 37
Figure 3 – Bank isolated from ground (containers connected to ground) . 37
Figure 4 – Bank connected to ground . 38
Figure 5 – Air clearance versus AC withstand . 41
Figure E.1 – Typical connections between capacitor units . 52
Figure E.2 – Typical connections between elements within a capacitor unit . 53

Table 1 – Letter symbols for upper limit of temperature range . 12
Table 2 – Ambient air temperature for the thermal stability test . 18
Table 3 – Standard insulation levels for range I (1 kV < U <245 kV) . 25
m
Table 4 – Standard insulation levels for range II (U > 245 kV) . 26
m
Table 5 – Admissible voltage levels in service . 27
Table 6 – Insulation requirements . 36
Table 7 – Specific creepage distances . 38
Table 8 – Correlation between standard lightning impulse withstand voltages and
minimum air clearances (Table A.1 from IEC 60071-2:1996) . 40

– 6 – IEC 60871-1:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SHUNT CAPACITORS FOR AC POWER SYSTEMS
HAVING A RATED VOLTAGE ABOVE 1 000 V –

Part 1: General
FOREWORD
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60871-1 has been prepared by IEC technical committee 33: Power
capacitors and their applications.
This fourth edition cancels and replaces the third edition published in 2005. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the overvoltage cycling test has been moved to this standard from the IEC 60871-2;
b) the ranges of the standardized values of the highest voltage for equipment have been
modified:
c) for installations installed on altitudes above 1 000 m a correction factor to all insulation
requirements has been introduced;
d) new standard insulation tables have been defined;

The text of this standard is based on the following documents:
FDIS Report on voting
33/559/FDIS 33/564/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60871 series, published under the general title Shunt capacitors
for a.c. power systems having a rated voltage above 1 000 V, can be found on the IEC
website.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
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.
– 8 – IEC 60871-1:2014 © IEC 2014
SHUNT CAPACITORS FOR AC POWER SYSTEMS
HAVING A RATED VOLTAGE ABOVE 1 000 V –

Part 1: General
1 Scope
This part of IEC 60871 is applicable to both capacitor units and capacitor banks intended to
be used, particularly, for power-factor correction of a.c. power systems having a rated voltage
above 1 000 V and frequencies of 15 Hz to 60 Hz.
This part of IEC 60871 also applies to capacitors intended for use in power filter circuits.
Additional definitions, requirements and tests for filter capacitors are given in Annex B.
Additional requirements for capacitors protected by internal fuses as well as requirements for
the internal fuses are given in IEC 60871-4.
Requirements for capacitors to be protected by external fuses, as well as requirements for the
same, are given in Annex C.
This standard does not apply to capacitors of the self-healing metallized dielectric type.
The following capacitors are excluded from this part of IEC 60871:
– capacitors for inductive heat-generating plants operating at frequencies between 40 Hz
and 24 000 Hz (IEC 60110-1);
– series capacitors for power systems (see the IEC 60143 series);
– capacitors for motor applications and the like (see the IEC 60252 series);
– coupling capacitors and capacitor dividers (IEC 60358);
– shunt capacitors for a.c. power systems having rated voltage up to and including 1 000 V
(see the IEC 60831 and IEC 60931 series);
– small a.c. capacitors to be used for fluorescent and discharge lamps (IEC 61048 and
IEC 61049);
– capacitors to be used in power electronic circuits (IEC 61071);
– capacitors for microwave ovens (IEC 61270-1);
– capacitors for suppression of radio interference;
– capacitors intended for use with a.c. voltage superimposed on d.c. voltage.
Accessories such as insulators, switches, instrument transformers, external fuses, etc. are in
accordance with the relevant IEC standards.
The object of this part of IEC 60871 is as follows:
a) to formulate uniform rules regarding the performance and rating of units and banks, and
the testing of units;
b) to formulate specific safety rules;
c) to provide a guide for installation and operation.

2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60071-1:2006, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60549, High-voltage fuses for the external protection of shunt capacitors
IEC 60815 (all parts), Selection and dimensioning of high-voltage insulators intended for use
in polluted conditions
IEC 60871-4:1996, Shunt capacitors for AC power systems having a rated voltage above
1 000 V – Part 4: Internal fuses
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
capacitor element
element
device consisting essentially of two electrodes separated by a dielectric
[SOURCE: IEC 60050-436:1990, 436-01-03]
3.2
capacitor unit
assembly of one or more capacitor elements in the same container with terminals brought out
[SOURCE: IEC 60050-436:1990, 436-01-04]
3.3
capacitor bank
bank
number of capacitor units connected so as to act together
[SOURCE: IEC 60050-436:1990, 436-01-06]
3.4
capacitor
two-terminal device characterized essentially by its capacitance
Note 1 to entry: The term "capacitor" is used when it is not necessary to specify whether a capacitor unit or
capacitor bank is meant.
[SOURCE: IEC 60050-151:2001, 151-13-28]
3.5
capacitor installation
one or more capacitor banks and their accessories

– 10 – IEC 60871-1:2014 © IEC 2014
[SOURCE: IEC 60050-436:1990, 436-01-07]
3.6
discharge device of a capacitor
device which may be incorporated in a capacitor, capable of reducing the voltage between the
terminals practically to zero, within a given time, after the capacitor has been disconnected
from a network
[SOURCE: IEC 60050-436:1990, 436-03-15, modified by replacement of “intended to” by
“capable of” and of “to a given value” by “practically to zero”]
3.7
internal fuse of a capacitor
fuse connected inside a capacitor unit, in series with an element or a group of elements
[SOURCE: IEC 60050-436:1990, 436-03-16]
3.8
line terminal
terminal intended for connection to a line conductor of a network
Note 1 to entry: In polyphase capacitors, a terminal intended to be connected to the neutral conductor is not
considered to be a line terminal.
[SOURCE: IEC 60050-436:1990, 436-03-01, modified by addition of Note 1]
3.9
rated capacitance of a capacitor
C
N
capacitance value derived from the values of rated output, voltage and frequency of the
capacitor
[SOURCE: IEC 60050-436:1990, 436-01-12, modified by addition of “C ”]
N
3.10
rated output of a capacitor
Q
N
reactive power for which the capacitor has been designed
[SOURCE: IEC 60050-436:1990, 436-01-16, modified by addition of “Q ”]
N
3.11
rated voltage of a capacitor
U
N
r.m.s. value of the alternating voltage for which the capacitor has been designed
Note 1 to entry: In the case of capacitors consisting of one or more separate circuits (for example single-phase
units intended for use in polyphase connection, or polyphase units with separate circuits), U refers to the rated
N
voltage of each circuit.
For polyphase capacitors with internal electrical connections between the phases, and for polyphase capacitor
banks, U refers to the phase-to-phase voltage.
N
[SOURCE: IEC 60050-436:1990, 436-01-15, modified by addition of “U ” and Note 1]
N
3.12
rated frequency of a capacitor
f
N
frequency for which the capacitor has been designed

[SOURCE: IEC 60050-436:1990, 436-01-14, modified by addition of “f ”]
N
3.13
rated current of a capacitor
I
N
r.m.s. value of the alternating current for which the capacitor has been designed
[SOURCE: IEC 60050-436:1990, 436-01-13, modified by addition of “I ”]
N
3.14
capacitor losses
active power dissipated in the capacitor
Note 1 to entry: All loss-producing components should be included, for example:
– for a unit, losses from dielectric, internal fuses, internal discharge resistor, connections, etc;
– for a bank, losses from units, external fuses, busbars, discharge and damping reactors, etc.
Note 2 to entry: The capacitor losses may be recalculated as an equivalent series resistor to the unit and/or bank.
[SOURCE: IEC 60050-436:1990, 436-04-10, modified by addition of Note 1]
3.15
tangent of the loss angle (of a capacitor)
tan δ
ratio between the equivalent series resistance and the capacitive reactance of the capacitor at
specified sinusoidal alternating voltage and frequency
[SOURCE: IEC 60050-436:1990, 436-04-11]
3.16
maximum permissible a.c. voltage of a capacitor
maximum r.m.s. alternating voltage which the capacitor can sustain for a given time in
specified conditions
[SOURCE: IEC 60050-436:1990, 436-04-07]
3.17
maximum permissible a.c. current of a capacitor
maximum r.m.s. alternating current which the capacitor can sustain for a given time in
specified conditions
[SOURCE: IEC 60050-436:1990, 436-04-09]
3.18
ambient air temperature
temperature of the air at the proposed location of the capacitor
3.19
cooling air temperature
temperature of the cooling air measured at the hottest position in the bank, under steady-state
conditions, midway between two units
Note 1 to entry: If only one unit is involved, it is the temperature measured at a point approximately 0,1 m away
from the capacitor container and at two-thirds of the height from its base.

– 12 – IEC 60871-1:2014 © IEC 2014
3.20
steady-state condition
thermal equilibrium attained by the capacitor at constant output and at constant ambient air
temperature
3.21
residual voltage
voltage remaining on the terminals of a capacitor at a certain time following disconnection
4 Service conditions
4.1 Normal service conditions
This standard gives requirements for capacitors intended for use in the following conditions:
a) Residual voltage at energization
This shall not exceed 10 % of the rated voltage (see Clause 21, Subclause 19.2 and
Annex D).
b) Altitude
If the altitude exceeds 1 000 m above sea level a correction factor shall be applied to all
external insulation requirements as stipulated in Clause 18.
c) Ambient air temperature categories
Capacitors are classified in temperature categories, each category being specified by a
number followed by a letter. The number represents the lowest ambient air temperature at
which the capacitor may operate. The letters represent upper limits of temperature
variation ranges, having maximum values specified in Table 1. The temperature categories
cover the temperature range of –50 °C to +55 °C.
The lowest ambient air temperature at which the capacitor may be operated should be
chosen from the five preferred values +5 °C, –5 °C, –25 °C, –40 °C, –50 °C.
NOTE With the agreement of the manufacturer, the capacitor can be used at a lower temperature than the limits
above, provided that energization takes place at a temperature at or above these limits (see 27.3.1).
Table 1 is based on service conditions in which the capacitor does not influence the ambient
air temperature (for example outdoor installations).
Table 1 – Letter symbols for upper limit of temperature range
Ambient temperature
°C
Highest mean over any period of
Symbol Maximum
24 h 1 year
A 40 30 20
B 45 35 25
C 50 40 30
D 55 45 35
NOTE These temperature values can be found in the meteorological temperature tables covering the installation site.

If the capacitor influences the air temperature, the ventilation and/or choice of capacitor shall
be such that the Table 1 limits are maintained. The cooling air temperature in such an
installation shall not exceed the temperature limits of Table 1 by more than 5 °C.

Any combination of minimum and maximum values can be chosen for the standard
temperature category of a capacitor, for example –40/A or –5/C. Preferred standard
temperature categories are: –40/A, –25/A, –5/A and –5/C.
4.2 Unusual service conditions
Unless otherwise agreed between manufacturer and purchaser, this standard does not apply
to capacitors, the service conditions of which, in general, are incompatible with the
requirements of the present standard.
5 Quality requirements and tests
5.1 General
Clauses 5 to 17 give the test requirements for capacitor units.
Supporting insulators, switches, instrument transformers, external fuses, etc. shall be in
accordance with relevant IEC standards.
NOTE The year of issue (version number) of referred standards is given in test reports.
5.2 Test conditions
Unless otherwise specified for a particular test or measurement, the temperature of the
capacitor dielectric shall be in the range +5 °C to +35 °C.
When a correction has to be applied, the reference temperature to be used is +20 °C, unless
otherwise agreed between the manufacturer and the purchaser.
It may be assumed that the dielectric temperature of the capacitor unit is the same as the
ambient temperature, provided that the capacitor has been left in an unenergized state at a
constant ambient temperature for an adequate period.
The a.c. tests and measurements shall be carried out at a frequency of 50 Hz or 60 Hz
independent of the rated frequency of the capacitor, if not otherwise specified.
6 Classification of tests
6.1 General
The tests are classified as routine tests, type tests and acceptance tests.
6.2 Routine tests
a) Capacitance measurement (see Clause 7).
b) Measurement of the tangent of the loss angle (tan δ) of the capacitor (see Clause 8).
c) Voltage test between terminals (see Clause 9).
d) AC voltage test between terminals and container (see Clause 10).
e) Test of internal discharge device (see Clause 11).
f) Sealing test (see Clause 12).
g) Discharge test on internal fuses (see 5.1.1 of IEC 60871-4:1996).
Routine tests shall have been carried out by the manufacturer on every capacitor before
delivery. If the purchaser so requests, he shall be supplied with a certificate detailing the
results of such tests. The test sequence above is not mandatory.

– 14 – IEC 60871-1:2014 © IEC 2014
6.3 Type tests
a) Thermal stability test (see Clause 13).
b) Measurement of the tangent of the loss angle (tan δ) of the capacitor at elevated
temperature (see Clause 14).
c) AC voltage test between terminals and container (see 15.1).
d) Lightning impulse voltage test between terminals and container (see 15.2).
e) Overvoltage test (see Clause 16).
f) Short-circuit discharge test (see Clause 17).
g) Discon
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