SIST EN 60143-2:2000
(Main)Series capacitors for power systems -- Part 2: Protective equipment for series capacitor banks
Series capacitors for power systems -- Part 2: Protective equipment for series capacitor banks
Covers protective equipment for series capacitor banks, with a size larger than 10 Mvar per phase. Protective equipment is the main circuit apparatus and ancillary equipment, which are part of a series of capacitor installations, but which are external to the capacitor part itself.
Reihenkondensatoren für Starkstromanlagen -- Teil 2: Schutzeinrichtungen für Reihenkondensatorbatterien
Condensateurs série destinés à être installés sur des réseaux -- Partie 2: Matériel de protection pour les batteries de condensateurs série
Concerne les matériels de protection pour les batteries de condensateurs série, de puissance supérieure à 10 Mvar par phase. Le matériel de protection étant l'appareillage de circuit principal et du matériel auxiliaire, qui font partie de l'installation des condensateurs série, mais qui sont à l'extérieur de la partie constituée par les condensateurs eux-mêmes.
Series capacitors for power systems - Part 2: Protective equipment for series capacitor banks
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 60143-2:2000
01-september-2000
Series capacitors for power systems - Part 2: Protective equipment for series
capacitor banks
Series capacitors for power systems -- Part 2: Protective equipment for series capacitor
banks
Reihenkondensatoren für Starkstromanlagen -- Teil 2: Schutzeinrichtungen für
Reihenkondensatorbatterien
Condensateurs série destinés à être installés sur des réseaux -- Partie 2: Matériel de
protection pour les batteries de condensateurs série
Ta slovenski standard je istoveten z: EN 60143-2:1994
ICS:
31.060.70 0RþQRVWQLNRQGHQ]DWRUML Power capacitors
SIST EN 60143-2:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 60143-2:2000
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SIST EN 60143-2:2000
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SIST EN 60143-2:2000
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SIST EN 60143-2:2000
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SIST EN 60143-2:2000
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SIST EN 60143-2:2000
CEI
NORME
IEC
INTERNATIONALE
143-2
INTERNATIONAL
Première édition
STANDARD
First edition
1994-07
Condensateurs série destinés à être installés
sur des réseaux —
Partie 2:
Matériel de protection pour les batteries
de condensateurs série
—
Series capacitors for power systems
Part 2:
Protective equipment for series capacitor banks
réservés — Copyright — all rights reserved
© CEI 1994 Droits de reproduction
No part of this publication may be reproduced or utilized in
Aucune partie de cette publication ne peut être reproduite ni
any form or by any means, electronic or mechanical,
utilisée sous quelque forme que ce soit et par aucun pro-
including photocopying and microfilm, without permission
cédé, électronique ou mécanique, y compris la photocopie et
in writing from the publisher.
les microfilms, sans l'accord écrit de l'éditeur.
Genève, Suisse
Bureau Central de la Commission Electrotechnique Inte rnationale 3, rue de Varembé
Commission Electrotechnique Internationale CODE PRIX
Commission
International Electrotechnical XA
PRICE CODE
MewityHapoaHan 3nekrporexHH gecnaa HoMHCCHn
IEC
Pour prix, voir catalogue en vigueur
• •
For price, see current catalogue
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SIST EN 60143-2:2000
143-2 ©IEC:1994 – 3 –
CONTENTS
Page
FOREWORD 7
Clause
SECTION 1: GENERAL
9
1.1 Scope and object
11
1.2 Normative references
15
1.3 Definitions
SECTION 2: QUALITY REQUIREMENTS AND TESTS
25
2.1 Overvoltage protector
2.1.1 Protective spark gap 27
2.1.1.1 Purpose 27
27
2.1.1.2 Classification
27
2.1.1.3 Tests
31
2.1.2 Non-linear resistor (varistor)
31
2.1.2.1 Purpose
31
2.1.2.2 Classification
33
2.1.2.3 Tests
43
2.2 By-pass circuit-breaker
43
2.2.1 Purpose
43
2.2.2 Classification
45
2.2.3 Tests
2.3 Disconnectors 49
2.3.1 Purpose 49
49
2.3.1.1 By-pass disconnector
49
2.3.1.2 Series disconnector
49
2.3.2 Classification
2.3.3 Tests 49
51
2.4 Current-limiting damping equipment
51
2.4.1 Purpose
51
2.4.2 Classification
53
2.4.3 Tests
59
2.5 Discharge reactor
59
2.5.1 Purpose
59
2.5.2 Classification
59
2.5.3 Tests
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SIST EN 60143-2:2000
143-2 ©IEC:1994 — 5 —
Clause Page
61 2.6 Voltage transformer
61
2.6.1 Purpose
61 2.6.2 Classification
63
2.6.3 Tests
63
2.7 Current transformer
63
2.7.1 Purpose
63
2.7.2 Classification
63
2.7.3 Tests
63
2.8 Signal column
63
2.8.1 Purpose
65
2.8.2 Classification
65
2.8.3 Tests
2.9 Relay protection, control equipment and platform to ground
65
communication equipment
65
2.9.1 Purpose
67
2.9.2 Classification
71
2.9.3 Tests
SECTION 3: GUIDE
71
3.1 General
71 3.2 Specification data for series capacitors
73 3.3 Protective spark gap
75 3.4 Non-linear resistor (varistor)
89
3.5 By-pass circuit-breaker
3.6 Disconnectors 91
3.7 Current-limiting damping equipment 91
3.8 Discharge reactor 95
97
3.9 Voltage transformer
3.10 Current transformer 97
3.11 Relay protection, control equipment and platform to ground communication
equipment 97
97
3.12 Precommissioning tests
3.13 Commissioning tests 99
101
Annex A— Bibliography
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SIST EN 60143-2:2000
143-2 ©IEC:1994 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
SERIES CAPACITORS
FOR POWER SYSTEMS -
Part 2: Protective equipment for series
capacitor banks
FOREWORD
The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
1)
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
Their preparation is entrusted to technical committees; any IEC National Committee interested in
the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
2)
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use published in the form of standards, technical
3)
reports or guides and they are accepted by the National Committees in that sense.
In order to promote international unification, IEC National Committees undertake to apply IEC International
4)
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
5)
equipment declared to be in conformity with one of its standards.
International Standard IEC 143-2 has been prepared by IEC technical committee 33:
Power capacitors.
The text of this standard is based on the following documents:
DIS Report on Voting
33(CO)115 33(CO)124
Full information on the voting for the approval of this standard can be found in the report
on voting indicated in the above table.
IEC 143 consists of the following parts, under the general title: Power capacitors:
143: 1992, Series capacitors for power systems (when revised, this standard will become
–
IEC 143-1);
143-2: 1994, Series capacitors for power systems – Part 2: Protective equipment for series
–
capacitor banks.
Other parts are under consideration.
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SIST EN 60143-2:2000
143-2 © IEC:1994 - 9 -
SERIES CAPACITORS
FOR POWER SYSTEMS -
Part 2: Protective equipment for series
capacitor banks
Section 1: General
1.1 Scope and object
This pa rt of IEC 143 covers protective equipment for series capacitor banks, with a size
larger than 10 Mvar per phase. Protective equipment is defined as the main circuit appa-
ratus and ancillary equipment, which are part of a series capacitor installation, but which
are external to the capacitor part itself. The recommendations for the capacitor part are
given in IEC 143. The protective equipment is mentioned in clauses 1.3 and 7.6 of
IEC 143.
The protective equipment, treated in this standard, comprises the following items listed
below.
- overvoltage protector,
- protective spark gap,
non-linear resistor (varistor),
- by-pass circuit-breaker,
disconnectors,
- current-limiting damping equipment,
- discharge reactor,
- voltage transformer,
- current transformer,
- signal column,
relay protection, control equipment and platform to ground communication
equipment.
See figure 1.
Principles involved in the application and operation of series capacitors are given in
section 3.
Examples of fault scenarios are given in section 3.
Examples of protective schemes utilizing different overvoltage protectors are given in
clause 2.1.
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SIST EN 60143-2:2000
143-2 ©IEC:1994 -11 -
3
Module 1 Module N
Segment AN
Segment Al !
1
4 4 Phase
Phase A
• bank A
F
Segment B1 Segment BN
Phase
4
Phase B
bank B
°\
Segment CN
Segment Cl
Phase
4
Phase C
bank C
L L
IEC 673194
1 Assembly of capacitor units,
2 Main protective equipment for a segment,
3 By-pass disconnector,
4 Series disconnector.
Figure 1 - Series capacitor bank nomenclature
NOTE - Capacitor fuses are not treated in this standard, since they are treated in IEC 143 and IEC 595.
The object of this standard is:
to formulate uniform rules regarding pe rformance, testing and rating,
-
to illustrate different kinds of overvoltage protectors,
-
- to provide a guide for installation and operation.
1.2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this part of IEC 143. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and pa rties to agree-
ments based on this part of IEC 143 are encouraged to investigate the possibility of apply-
ing the most recent editions of the normative documents indicated below. Members of IEC
and ISO maintain registers of currently valid International Standards.
The following IEC publications and reports are quoted in this standard:
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SIST EN 60143-2:2000
-13 -
143-2 ©IEC:1994
4: Measurement of pa rtial discharges
IEC 44-4: 1980, Instrument transformers - Pa rt
International Electrotechnical Vocabulary (IEV)- Chapter 436: Power
IEC 50(436): 1990,
Capacitors
High-voltage alternating-current circuit-breakers
IEC 56: 1987,
High-voltage test techniques - Part 1: General definitions and test
IEC 60-1: 1989,
requirements
Basic environmental testing procedures - Part 2: Tests - Test Db and
IEC 68-2-30: 1980,
guidance: Damp heat, cyclic (12 + 12 hour cycle)
IEC 76-1, 1993, Power transformers - Part 1: General
IEC 99-1: 1991, Surge arresters - Part 1 : Non-linear resistor type gapped arresters for
a.c. systems
IEC 99-4: 1991, Surge arresters - Part 4: Metal-oxide surge arresters without gaps for a.c.
systems
IEC 129: 1984, Alternating current disconnectors and earthing switches
Series capacitors for power systems
IEC 143: 1992,
IEC 185: 1987, Current transformers
Voltage transformers
IEC 186: 1987,
Electrical relays - Part 6: Measuring relays and protection equipment
IEC 255-6: 1988,
IEC 289: 1988, Reactors
rts 1-2): 1993, Tests on insulators of ceramic material or glass for overhead
IEC 383 (Pa
lines with a nominal voltage greater than 1 000 V
Internal fuses for series capacitors
IEC 595: 1977,
Amendment 2, 1987
IEC 654 (Parts 1-4): 1979-1987, Operating conditions for industrial-process measurement
and control equipment
Common clauses for high-voltage switchgear and controlgear standards
IEC 694: 1980,
1: Generic specification
IEC 794-1: 1993, Optical fibre cables - Part
2: Product specifications
IEC 794-2: 1989, Optical fibre cables - Part
NOTE - No standard exists for varistors for series capacitors (S.C.). The relevant tests for series
capacitors varistors are therefore dealt with in this standard.
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SIST EN 60143-2:2000
– 15 --
143-2©IEC:1994
1.3 Definitions
of IEC 143, the following definitions apply:
For the purpose of this pa rt
1.3.0 definitions of capacitor parts and accessories: They are in accordance with
IEC 143.
Supplementary gap which may be set to spark over at a voltage
1.3.1 back-up gap:
level higher than the protective level of the primary protective device, and which is
normally placed in parallel with the primary protective device.
1.3.2 bank protection: General term for all protective equipment for a capacitor bank,
or part thereof.
1.3.3 by-pass current: Current flowing through the by-pass device or devices in
parallel with the series capacitor. This current can either be a fault current or a normal
current.
Device such as a switch or a circuit-breaker used in parallel with
1.3.4 by-pass device:
a series capacitor and its overvoltage protector to shunt line current for a specified time,
or continuously. Besides by-passing the capacitor, this device may also have the capabil-
ity of inserting the capacitor into a circuit and carrying a specified current.
Device to short-circuit the series capacitor after it is
1.3.5 by-pass disconnector:
by-passed by the by-pass device.
fault current: Current flowing through the by-passed series capacitor
1.3.6 by-pass
bank caused by a fault on the line.
gap): Gap, or system of gaps, to protect either the
1.3.7 by-pass gap (protective
capacitor (Type K) against overvoltage or the non-linear resistor (Type M) against
rts for a specified time.
overload by carrying load or fault current around the protected pa
Device that requires all three poles of the by-pass
1.3.8 by-pass interlocking device:
device to be in the same open or closed position.
1.3.9 capacitance unbalance protection: Device to detect unbalance in capacitance
between capacitor groups within a phase, such as that caused by blown capacitor fuses or
faulted capacitors, and to initiate an alarm or the closing of the by-pass device, or both.
s the capacitor/rack assemblies and all
1.3.10 capacitor platform: Structure that suppo rt
associated equipment and protective devices, and is supported on insulators compatible
with phase-to-earth insulation requirements.
1.3.11 capacitor switching step: See module.
1.3.12 continuous operating voltage (COV = MCOV) (U c) (of a varistor): The (Maximum)
value of power
Continuous Operating Voltage, COV, is the designated permissible r.m.s.
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SIST EN 60143-2:2000
143-2 ©IEC:1994 – 17 –
r.m.s. frequency voltage that may be applied continuously between the varistor terminals.
NOTES
1 COV of the series capacitor varistor is usually equal to the rated voltage of the series capacitor. This
definition is different from the definition of COV for a ZnO arrester according to IEC 99-4.
2 Consideration to short-time overvoltages of the series capacitor, such as voltages produced by swing
currents and overload currents, should be taken into account when the protective level of the varistor is
determined.
limiting damping equipment: Reactor or a reactor with a parallel
1.3.13 current-
connected resistor to limit the current magnitude and frequency and to provide a sufficient
damping of the oscillation of the discharge of the capacitors upon operation of the by-pass
gap or the by-pass device (see figure 1).
1.3.14 discharge device: Device permanently connected across the terminals of the
capacitor or built into the capacitor unit, capable of reducing the residual voltage across
the capacitor after the capacitor has been disconnected from the supply.
residual voltage.
1.3.15 discharge voltage (of a varistor): See
1.3.16 external fault: Line fault occurring outside the protected line section containing
the series capacitor bank.
Fault appearing within the capacitor bank (for
1.3.17 fault within the capacitor bank:
example changes of the capacitance within a segment, platform fault, etc.). Such faults
should be handled by the protection of the series capacitor bank and cleared without the
interruption of the transmission line.
fault-to-platform protection: Device to detect insulation failure on the platform
1.3.18
that results in current flowing from normal current-carrying circuit elements to the platform
and to initiate the closing of the by-pass device.
Opening of the by-pass device to place the series capacitor in service
1.3.19 insertion:
with or without load current flowing.
current: Steady-state root-mean-square current that flows through the
1.3.20 insertion
series capacitor after the by-pass device has opened.
Steady-state root-mean-square voltage appearing across the
1.3.21 insertion voltage:
series capacitor upon interruption of the by-pass current with the opening of the by-pass
device.
internal fault: Line fault occurring within the protected line section containing the
1.3.22
series capacitor bank.
Combination of test voltage values (both power-frequency and
1.3.23 insulation level:
impulse) which characterizes the insulation of the capacitor bank with regard to its
capability of withstanding the electric stresses between platform and earth, between
phases, between terminals of all equipment and between platform-mounted equipment and
the platform.
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SIST EN 60143-2:2000
lEC:1994 –19 –
143-2 ©
1.3.24 leakage current (of a varistor): The leakage current is the continuous current
flowing through the varistor when energized at a specified power-frequency voltage.
NOTE — At COV, and at a varistor element temperature equal to normal ambient temperature, the leakage
current is usually capacitive.
The maximum instantaneous voltage appearing between
1.3.25 limiting voltage (Utim):
the capacitor terminals divided by Irf. This voltage appears either during operating of the
varistor or immediately before ignition of the spark gap.
loss-of-control-power protection: A means to initiate the closing of the by-pass
1.3.26
device upon the loss of normal control power.
of the protective spark gap, that shall carry the fault current
1.3.27 main gap: That pa rt
during a specified time, comprising two or more heavy-duty electrodes.
continuous operating voltage (of a varistor).
1.3.28 MCOV: See
metal-oxide varistor: See varistor.
1.3.29
varistor element.
1.3.30 metal-oxide varistor element: See
metal-oxide varistor column: See varistor column.
1.3.31
1.3.32 metal-oxide varistor group: See varistor group.
-oxide varistor unit: See varistor unit.
1.3.33 metal
(of a varistor): The minimum permissible
1.3.34 minimum reference voltage
UMRef
reference voltage for a complete varistor or varistor unit measured at a specified
temperature, typically (23 ± 5) °C (see figure 3 and comments in section 3).
A three-phase function unit, that consists of
module (capacitor switching step):
1.3.35
one capacitor segment (possibly several) per phase with provision for interlocked
operation of the single-phase by-pass devices (see figure 1).
1.3.36 non-linear resistor (varistor): A device to act as overvoltage protection of the
capacitor consisting of resistors with a non-linear voltage-dependent resistance (normally
metal-oxide varistors).
1.3.37 overvoltage protection: A quick-acting device which limits the instantaneous
voltage across the series capacitor to a permissible value at power-system faults or other
abnormal network conditions.
control power: Energy source(s) available at platform potential for
1.3.38 platform
performing operational and control functions.
platform-to-ground communication equipment: Devices to transmit operating,
1.3.39
control and alarm signals between the platform and ground level, as a result of operation
or protective actions.
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SIST EN 60143-2:2000
143-2 ©IEC:1994 - 21 -
1.3.40 protective gap: See by-pass gap.
1.3.41 protective level: The maximum instantaneous voltage appearing across the
capacitor immediately before or during operation of the by-pass gap (gap-scheme) or at a
specified instantaneous current through the varistor (varistor-scheme). In practice, the
protective level is equal to
Ulim.
The maximum energy the varistor can
1.3.42 rated short-time energy (of a varistor):
absorb within a short period of time, without being damaged due to thermal shock. The
short-time energy is usually expressed in J, kJ or MJ.
The peak value of the resistive component of a
1.3.43 reference current (of a varistor):
power-frequency current used to determine the reference voltage of the varistor. It is
chosen in the transition area between the leakage current and the conduction current
region, typically in the range 1 mA to 20 mA for a single varistor column (see figure 3 in
section 3).
The peak value of power-frequency voltage
1.3.44 reference voltage (of a varistor):
measured at the reference current of the varistor.
divided by
NOTE - Measurement of the reference voltage is necessary for the selection of correct test samples in
the type testing.
1.3.45 reinsertion: The restoration of load current to the series capacitor from the
by-pass path (see figure 1).
The transient current flowing through the series capacitor
1.3.46 reinsertion current:
during the reinsertion.
The transient voltage appearing across the series capacitor
1.3.47 reinsertion voltage:
during reinsertion.
residual voltage (of a capacitor): The voltage remaining between terminals of a
1.3.48
capacitor at a given time following disconnection of the supply.
The peak value of voltage that appears between
1.3.49 residual voltage (of a varistor):
the terminals of a varistor during passage of current.
section (of a varistor): A complete, suitably assembled pa rt of a varistor
1.3.50
necessary to represent the behaviour of a complete varistor with respect to a particular
test. A section of a varistor is not necessarily a unit of a varistor.
1.3.51 segment: Single-phase assembly of groups of capacitors which has its own
voltage-limiting devices and relays to protect the capacitors from overvoltages and
overloads (see figure 1).
Devices to disconnect the by-passed series capacitor from
1.3.52 series disconnector:
the line, for example for maintenance.
1.3.53 subharmonic protection: A device that detects subharmonic current of specified
frequency and duration and initiates an alarm signal or corrective action, usually
by-passing the capacitor bank.
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SIST EN 60143-2:2000
143-2 © IEC:1994 – 23 –
A means to detect prolonged current flow
1.3.54 sustained by-pass current protection:
through the overvoltage protector and to initiate closing of the by-pass device.
A device that detects capacitor voltage above
1.3.55 sustained overload protection:
rating but below the operating level of the overvoltage protector and initiates an alarm
signal or corrective action.
A temporary power-frequency voltage higher than the
1.3.56 temporary overvoltage:
continuous rated voltage of the series capacitor.
A section assembled in a suitable housing with
1.3.57 thermal section (of a varistor):
the same heat transfer capability as the actual varistor.
thermal runaway (of a varistor): Varistor condition when the sustained power
1.3.58
losses of the varistor elements steadily increase due to increased temperature, when the
varistor is energized. The heat generated by the power losses of the varistor elements
exceeds the cooling capability of the varistor housing, which causes further temperature
rise and finally leads to a varistor failure.
thermal stability (of a varistor): Varistor condition after a temperature rise, due
1.3.59
to an energy discharge and/or temporary overvoltage, when the varistor is energized at its
COV under specified ambient conditions and the temperature of the varistor elements
decreases with time.
It is the opposite of a "thermal runaway".
A device to ignite the main gap at a specified voltage level or by
1.3.60 trigger circuit:
external command.
Term used, when it is not necessary to distinguish between varistor
1.3.61 varistor:
element, varistor unit or varistor group.
varistor element: A dense ceramic cylindrical body, with metallized parallel end
1.3.62
aces, constituting the smallest active component used in larger varistor assemblies.
su rf
"n" varistor elements connected in series.
1.3.63 varistor column: A column comprising
1.3.64 varistor unit: An assembly of varistor elements, comprising one or several
varistor columns mounted in a suitable housing.
1.3.65 varistor group: Single-phase group of varistor units connected in parallel and/or
in series, carefully matched together, to form an overvoltage-limiting device for a series
capacitor.
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SIST EN 60143-2:2000
— 25 —
143-2 ©IEC:1994
Section 2: Quality requirements and tests
2.1 Overvoltage protector
a) Purpose
The overvoltage protector is a quick-acting device which limits the instantaneous voltage
across the series capacitor to a permissible value when that value would otherwise be
exceeded as a result of a power-system fault or other abnormal network condition.
Classification
b)
Four common alternatives are listed below.
single-protective spark gap;
—
two different set single-protective spark gaps forming a dual-gap system;
—
- non-linear resistor;
non-linear resistor with by-pass gap.
2.
See figure
Non-linear resistor
Single gap
IEC 674194
Non-linear resistor
Dual gap
with by-pass gap
Figure 2 — Classification of overvoltage protection
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SIST EN 60143-2:2000
143-2 ©IEC:1994 - 27 -
2.1.1 Protective spark gap
2.1.1.1 Purpose
The main purpose of the protective spark gap is to act as overvoltage protector for the
capacitor (type K, type L). In certain applications, the purpose of the spark gap is to act as
back-up protection for the capacitor (type K) or protection for the non-linear resistor
(type M). Reference is made to subclause 7.6.2 of IEC 143.
2.1.1.2 Classification
The protective spark gaps can be classified as follows, with regard to the working
principle:
type K - spark gap with sustained arc
-
- type L - spark gap with repetitive arc
With regard to triggering principles, i.e. how spark over of the main gap is initiated, the
following two principles can be distinguished:
self triggering;
-
- forced triggering
See further IEC 143, subclause 7.6.2.
2.1.1.3 Tests
For practical reasons, certain tests could be performed on the main gap and trigger circuit
separately. However, a type test on the total gap assembly is also necessary. The test
shall verify that the complete gap, comprising main gap and trigger gap operates correctly.
2.1.1.3.1 Main gap
2.1.1.3.1.1 Type tests
Fault current test
The following factors shall be considered:
- the test shall be made only once;
magnitude of test current shall conform with maximum power-frequency fault cur-
rent (r.m.s.) through the protective gap;
duration of test current shall conform with duration of fault current through the gap
-
at the series capacitor bank location. Fault scenarios and maximum back-up line
circuit-breaker fault-clearing time shall be taken into account (typical fault scenarios are
given in section 3 of the guide);
- criteria for acceptance of the tests: No excessive erosion nor significant change in
spark over voltage of the gap shall occur.
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SIST EN 60143-2:2000
143-2 ©IEC:1994 - 29 -
Discharge current test
The following factors shall be considered:
- the magnitude of the test current shall be the calculated sum of the high-frequency
discharge current component at maximum gap setting and the instantaneous value of
the power-frequency fault current component including offset;
- test current frequency shall conform with the discharge current frequency of the
actual series capacitor bank. A 50 Hz or 60 Hz half-current wave from a short-circuit
generator may also be used. In that case, the current amplitude shall be reduced
by 10 %. Such a test is considered more severe compared to a discharge test at the
actual discharge frequency;
the discharge current test shall normally be repeated 10 times. However, if the
-
capacitor in service is expected to be subjected to frequent discharges, the number of
discharges may, by agreement, be increased to 20 (see IEC 143, clause 2.13, note 2);
criteria for acceptance of the test: no mechanical damage, excessive erosion, nor
-
significant change in spark over voltage of the gap shall occur.
Recovery voltage test
The following factors shall be considered:
the gap shall be exposed to power-frequency fault currents of specified
-
magnitude(s) and duration(s) corresponding to external line faults and/or internal line
faults. The withstand voltage versus time for the gap shall be recorded at specified time
intervals;
the test shall demonstrate that the gap has sufficient recovery voltage withstand
-
taking into account the trigger circuit, to allow the capacitor to be reinserted after a
successful line auto reclosure.
Self-clearing ability of self-extinguishing gap:
The gap shall be able to reinsert the capacitor at 150 % of rated current within four cycles.
Routine tests
2.1.1.3.1.2
- dimensional inspection;
routine test and inspection of spark-gap components, for example electrodes,
-
porcelain housings, grading components, bushings and support insulators, according to
relevant IEC standards.
Trigger circuit
2.1.1.3.2
2.1.1.3.2.1 Self-triggered circuit type tests
A routine test shall be performed before the type test is carried out.
spark over test
The test shall demonstrate that spark over occurs within the specified tolerance range.
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SIST EN 60143-2:2000
143-2 ©IEC:1994 - 31 -
Environmental test
The test shall demonstrate that the gap works correctly within its tolerance range,
for the specified ambient conditions, such as temperature, air pressure, etc.
...
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