EN 61954:2011

SLOVENSKI STANDARD
01-september-2011
6WDWLþQLNRPSHQ]DWRUMLMDORYHHQHUJLMHYDU3UHVNXãDQMHWLULVWRUVNLKHOHNWURQN
Static VAR compensators (SVC) - Testing of thyristor valves
Static VAR compensators (SVC) - Testing of thyristor valves
Compensateurs statiques de puissance réactive (SVC) - Essais des valves à thyristors
Ta slovenski standard je istoveten z: EN 61954:2011
ICS:
29.240.99 'UXJDRSUHPDY]YH]L] Other equipment related to
RPUHåML]DSUHQRVLQ power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks
31.080.20 Tiristorji Thyristors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61954
NORME EUROPÉENNE
June 2011
EUROPÄISCHE NORM
ICS 29.240.99; 31.080.20 Supersedes EN 61954:1999 + A1:2003

English version
Static VAR compensators (SVC) -
Testing of thyristor valves
(IEC 61954:2011)
Compensateurs statiques de puissance Static VAR compensators (SVC) -
réactive (SVC) - Testing of thyristor valves
Essais des valves à thyristors (IEC 61954:2011)
(CEI 61954:2011)
This European Standard was approved by CENELEC on 2011-05-26. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61954:2011 E
Foreword
The text of document 22F/217/CDV, future edition 2 of IEC 61954, prepared by SC 22F, Power
electronics for electrical transmission and distribution systems, of IEC TC 22, Power electronic systems
and equipment, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61954 on 2011-05-26.
This European Standard supersedes EN 61954:1999 + A1:2003.
EN 61954 :2011 includes the following significant technical changes with respect to
EN 61954:1999 + A1:2003:
a) Definitions of terms “thyristor level”, “valve section”, “valve base electronics” and ”redundant thyristor
levels” have been changed for clarification.
b) Conditions of testing thyristor valve sections instead of a complete thyristor valve have been defined.
c) The requirement has been added that if, following a type test, one thyristor level has become short-
circuited, then the failed level shall be restored and this type test repeated.
d) The time period of increasing the initial test voltage from 50 % to 100 % during type a.c. dielectric tests
on TSC, TCR or TSR valves has been set equal to approximately 10 s.
e) The duration of test voltage Uts2 during type a.c.-d.c. dielectric tests between TSC valve terminals and
earth as well as the duration of test voltage Utvv2 during dielectric tests between TSC valves (for MVU
only) has been changed from 30 min to 3 h.
f) The reference on the number of pulses per minute of the periodic partial discharge recorded during
a.c.-d.c. dielectric tests on TSC valves and exceeding the permissible level has been deleted.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:

– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2012-02-26
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2014-05-26
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61954:2011 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 61954:2011
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60060 Series High-voltage test techniques EN 60060 Series

IEC 60060-1 - High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements
IEC 60060-2 - High-voltage test techniques - EN 60060-2 -
Part 2: Measuring systems
IEC 60071 Series Insulation co-ordination EN 60071 Series

IEC 60071-1 2006 Insulation co-ordination - EN 60071-1 2006
Part 1: Definitions, principles and rules

IEC 60270 - High-voltage test techniques - Partial EN 60270 -
discharge measurements
IEC 60700-1 2008 Thyristor valves for high voltage direct current - -
(HVDC) power transmission –
Part 1: Electrical testing
IEC 61954 ®
Edition 2.0 2011-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Static var compensators (SVC) – Testing of thyristor valves

Compensateurs statiques de puissance réactive (SVC) – Essais des valves à
thyristors
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX X
ICS 29.240.99; 31.080.20 ISBN 978-2-88912-469-5

– 2 – 61954  IEC:2011
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 General requirements for type, production and optional tests . 9
4.1 Summary of tests . 9
4.2 Objectives of tests . 10
4.2.1 General . 10
4.2.2 Dielectric tests . 10
4.2.3 Operational tests . 10
4.2.4 Electromagnetic interference tests . 11
4.2.5 Production tests . 11
4.2.6 Optional tests . 11
4.3 Guidelines for the performance of type and optional tests . 11
4.4 Test conditions . 12
4.4.1 General . 12
4.4.2 Valve temperature at testing . 13
4.4.3 Redundant thyristor levels . 13
4.5 Permissible component failures during type testing . 14
4.6 Documentation of test results . 14
4.6.1 Test reports to be issued . 14
4.6.2 Contents of a type test report . 15
5 Type tests on TCR and TSR valves . 15
5.1 Dielectric tests between valve terminals and earth . 15
5.1.1 General . 15
5.1.2 AC test . 16
5.1.3 Lightning impulse test . 16
5.2 Dielectric tests between valves (MVU only) . 17
5.2.1 General . 17
5.2.2 AC test . 17
5.2.3 Lightning impulse test . 18
5.3 Dielectric tests between valve terminals . 18
5.3.1 General . 18
5.3.2 AC test . 18
5.3.3 Switching impulse test . 20
5.4 Operational tests . 21
5.4.1 Periodic firing and extinction test . 21
5.4.2 Minimum a.c. voltage test . 22
5.4.3 Temperature rise test . 23
6 Type tests on TSC valves . 23
6.1 Dielectric tests between valve terminals and earth . 23
6.1.1 General . 23
6.1.2 AC-DC test . 24
6.1.3 Lightning impulse test . 26
6.2 Dielectric tests between valves (for MVU only) . 26
6.2.1 General . 26
6.2.2 AC-DC test . 26

61954  IEC:2011 – 3 –
6.2.3 Lightning impulse test . 28
6.3 Dielectric tests between valve terminals . 29
6.3.1 General . 29
6.3.2 AC-DC test . 29
6.3.3 Switching impulse test . 31
6.4 Operational tests . 32
6.4.1 Overcurrent tests . 32
6.4.2 Minimum a.c. voltage test . 35
6.4.3 Temperature rise test . 36
7 Electromagnetic interference tests . 36
7.1 Objectives . 36
7.2 Test procedures . 36
7.2.1 General . 36
7.2.2 Switching impulse test . 37
7.2.3 Non-periodic firing test . 37
8 Production tests . 37
8.1 General . 37
8.2 Visual inspection . 37
8.3 Connection check . 37
8.4 Voltage-dividing/damping circuit check . 38
8.5 Voltage withstand check . 38
8.6 Check of auxiliaries . 38
8.7 Firing check . 38
8.8 Cooling system pressure test . 38
8.9 Partial discharge tests . 38
9 Optional tests on TCR and TSR valves . 38
9.1 Overcurrent test . 38
9.1.1 Overcurrent with subsequent blocking . 38
9.1.2 Overcurrent without blocking . 39
9.2 Positive voltage transient during recovery test . 39
9.2.1 Objectives . 39
9.2.2 Test values and waveshapes . 39
9.2.3 Test procedures . 40
9.3 Non-periodic firing test . 40
9.3.1 Objectives . 40
9.3.2 Test values and waveshapes . 40
9.3.3 Test procedures . 42
10 Optional tests on TSC valves . 42
10.1 Positive voltage transient during recovery test . 42
10.1.1 Test objective . 42
10.1.2 Test values and waveshapes . 42
10.1.3 Test procedures . 42
10.2 Non-periodic firing test . 43
10.2.1 Objectives . 43
10.2.2 Test values and waveshapes . 43
10.2.3 Test procedures . 44

Figure 1 – TSC branch . 33

– 4 – 61954  IEC:2011
Figure 2 – One-loop overcurrent . 34
Figure 3 – Two-loop overcurrent . 35

Table 1 – List of tests . 9
Table 2 – Number of thyristor levels permitted to fail during type tests . 15

61954  IEC:2011 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
STATIC VAR COMPENSATORS (SVC) –
TESTING OF THYRISTOR VALVES
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61954 has been prepared by subcommittee 22F: Power electronics
for electrical transmission and distribution systems, of IEC technical committee 22: Power
electronics.
This second edition cancels and replaces the first edition published in 1999, amendment 1
(2003) and constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Definitions of terms “thyristor level”, “valve section”, “valve base electronics” and
“”redundant thyristor levels” have been changed for clarification.
b) Conditions of testing thyristor valve sections instead of a complete thyristor valve have
been defined.
c) The requirement has been added that if, following a type test, one thyristor level has
become short-circuited, then the failed level shall be restored and this type test repeated.
d) The time period of increasing the initial test voltage from 50 % to 100 % during type a.c.

dielectric tests on TSC, TCR or TSR valves has been set equal to approximately 10 s.

– 6 – 61954  IEC:2011
e) The duration of test voltage U during type a.c.-d.c. dielectric tests between TSC valve

ts2
terminals and earth as well as the duration of test voltage U during dielectric tests
tvv2
between TSC valves (for MVU only) has been changed from 30 min to 3 h.
f) The reference on the number of pulses per minute of the periodic partial discharge
recorded during a.c.-d.c. dielectric tests on TSC valves and exceeding the permissible level
has been deleted.
The text of this standard is based on the following documents:
CDV Report on voting
22F/217/CDV 22F/231A/RVC
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.
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.
61954  IEC:2011 – 7 –
STATIC VAR COMPENSATORS (SVC) –
TESTING OF THYRISTOR VALVES
1 Scope
This International Standard defines type, production and optional tests on thyristor valves used
in thyristor controlled reactors (TCR), thyristor switched reactors (TSR) and thyristor switched
capacitors (TSC) forming part of static VAR compensators (SVC) for power system
applications. The requirements of the standard apply both to single valve units (one phase) and
to multiple valve units (several phases).
Clauses 4 to 7 detail the type tests, i.e. tests which are carried out to verify that the valve
design meets the requirements specified. Clause 8 covers the production tests, i.e. tests which
are carried out to verify proper manufacturing. Clauses 9 and 10 detail optional tests, i.e. tests
additional to the type and production tests.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60060 (all parts), High-voltage test techniques
IEC 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60060-2, High-voltage test techniques – Part 2: Measuring systems
IEC 60071 (all parts), Insulation co-ordination
IEC 60071-1:2006, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60270, High-voltage test techniques – Partial discharge measurements
IEC 60700-1:2008, Thyristor valves for high-voltage direct current (HVDC) power transmission
– Part 1: Electrical testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
thyristor level
part of a thyristor valve comprising a thyristor, or thyristors connected in parallel or antiparallel,
together with their immediate auxiliaries and reactor, if any
3.2
thyristor (series) string
series connected thyristors forming one direction of a thyristor valve

– 8 – 61954  IEC:2011
3.3
valve reactor
reactor incorporated within some valves for limitation of stresses
NOTE For testing purposes it is considered an integral part of the valve.
3.4
valve section
electrical assembly, comprising a number of thyristors and other components, which exhibits
pro-rated electrical properties of a complete thyristor valve but only a portion of the full voltage
blocking capability of the thyristor valve and which can be used for tests
3.5
thyristor valve
electrically and mechanically combined assembly of thyristor levels, complete with all
connections, auxiliary components and mechanical structures, which can be connected in
series with each phase of the reactor or capacitor of a SVC
3.6
valve structure
physical structure which insulates the valves to the appropriate level above earth potential and
from each other
3.7
valve base electronics
VBE
electronic unit, at earth potential, which is the interface between the control system of the SVC
and the thyristor valves
3.8
multiple valve unit
MVU
assembly of several valves in the same physical structure which cannot be separated for test
purposes (e.g. three-phase valves)
3.9
redundant thyristor levels
the maximum number of thyristor levels in the thyristor valve that may be short-circuited,
externally or internally, during service without affecting the safe operation of the thyristor valve
as demonstrated by type tests; and which if and when exceeded, would require either the
shutdown of the thyristor valve to replace the failed thyristors, or the acceptance of increased
risk of failures
3.10
voltage breakover (VBO) protection
means of protecting the thyristors from excessive voltage by firing them at a predetermined
voltage
61954  IEC:2011 – 9 –
4 General requirements for type, production and optional tests
4.1 Summary of tests
Table 1 lists the tests given in the following clauses and subclauses.
Table 1 – List of tests
Test Clause or subclause Test object
TCR/TSR TSC
Dielectric tests between valve terminals and earth (type tests)
AC test 5.1.2 Valve
AC-DC test 6.1.2 Valve
Lightning impulse test 5.1.3 6.1.3 Valve
Dielectric tests between valves (MVU only) (type tests)
AC test 5.2.2 MVU
AC-DC test 6.2.2 MVU
Lightning impulse test 5.2.3 6.2.3 MVU
Dielectric tests between valve terminals (type tests)
AC test 5.3.2 Valve
AC-DC test 6.3.2 Valve
Switching impulse test 5.3.3 6.3.3 Valve
Operational tests (type tests)
Periodic firing and extinction test 5.4.1 Valve or valve section
Overcurrent test 6.4.1 Valve or valve section
Minimum a.c. voltage test 5.4.2 6.4.2 Valve or valve section
Temperature rise test 5.4.3 6.4.3 Valve or valve section
Electromagnetic interference tests (type tests)
Switching impulse test 7.2.2 7.2.2 Valve
Non-periodic firing test 7.2.3 7.2.3 Valve
Production tests
Visual inspection 8.2 8.2
Connection check 8.3 8.3
Voltage dividing/damping circuit check 8.4 8.4
Voltage withstand check 8.5 8.5
Check of auxiliaries 8.6 8.6
Firing check 8.7 8.7
Cooling system pressure test 8.8 8.8
Partial discharge tests 8.9 8.9
Optional tests
Overcurrent test 9.1 Valve or valve section
Positive voltage transient during recovery test 9.2 10.1 Valve or valve section
Non-periodic firing test 9.3 10.2 Valve

– 10 – 61954  IEC:2011
4.2 Objectives of tests
4.2.1 General
The tests described apply to the valve (or valve sections), the valve structure and those parts
of the coolant distribution system and firing and monitoring circuits which are contained within
the valve structure or connected between the valve structure and earth. Other equipment, such
as valve control and protection and valve base electronics may be essential for demonstrating
the correct function of the valve during the tests but are not in themselves the subject of the
tests.
4.2.2 Dielectric tests
4.2.2.1 General
Tests for the following dielectric stresses are specified:
– a.c. voltage;
– combined a.c. and d.c. voltage (TSC only);
– impulse voltages.
In the interest of standardization with other equipment, lightning impulse tests between valve
terminals and earth and between phases of an MVU are included. For tests between valve
terminals, the only impulse test specified is a switching impulse.
4.2.2.2 Tests on valve structure
Tests are defined for the voltage withstand requirements between a valve (with its terminals
short-circuited) and earth, and also between valves for MVU. The tests shall demonstrate that
– sufficient clearances have been provided to prevent flashovers;
– there is no disruptive discharge in the insulation of the valve structure, cooling ducts, light
guides and other insulation parts of the pulse transmission and distribution systems;
– partial discharge inception and extinction voltages under a.c. and d.c. conditions are above
the maximum steady-state operating voltage appearing on the valve structure.
4.2.2.3 Tests between valve terminals
The purpose of these tests is to verify the design of the valve with respect to its capability to
withstand overvoltages between its terminals. The tests shall demonstrate that
– sufficient internal insulation has been provided to enable the valve to withstand specified
voltages;
– partial discharge inception and extinction voltages under a.c. and d.c. conditions are above
the maximum steady-state operating voltage appearing between valve terminals;
– the protective overvoltage firing system (if provided) works as intended;
– the thyristors have adequate du/dt capability for in-service conditions. (In most cases the
specified tests are sufficient; however in some exceptional cases additional tests may be
required).
4.2.3 Operational tests
The purpose of these tests is to verify the valve design for combined voltage and current
stresses under normal and abnormal repetitive conditions as well as under transient fault
conditions. They shall demonstrate that, under specified conditions:
– the valve functions properly;

61954  IEC:2011 – 11 –
– the turn-on and turn-off voltage and current stresses are within the capabilities of the
thyristors and other internal circuits;
– the cooling provided is adequate and no component is overheated;
– the overcurrent withstand capability of the valve is adequate.
4.2.4 Electromagnetic interference tests
The principal objective of these tests is to demonstrate the immunity of the valve to
electromagnetic interference from within the valve and from outside the valve. Generally,
immunity to electromagnetic interference is demonstrated by monitoring of the valve during
other tests.
4.2.5 Production tests
The objective of tests is to verify proper manufacture. The production tests shall demonstrate
that
– all materials, components and sub-assemblies used in the valve have been correctly
installed;
– the valve equipment functions as intended, and predefined parameters are within
prescribed acceptance limits;
– thyristor levels and valve or valve sections have the necessary voltage withstand capability;
– consistency and uniformity in production is achieved.
4.2.6 Optional tests
Optional tests are additional tests which may be performed, subject to agreement between the
purchaser and the supplier. The objectives are the same as for the operational tests specified
in 4.2.2. The test object is normally one valve or appropriate equivalent number of valve
sections.
4.3 Guidelines for the performance of type and optional tests
The following principles shall apply:
– type tests shall be performed on at least one valve or on an appropriate number of valve
sections, as indicated in Table 1 (see 4.1), to verify that the valve design meets the
specified requirements. All type tests shall be performed on the same valve(s) or valve
section(s);
– provided that the valve is demonstrably similar to one previously tested, the supplier may
submit a certified report of any previous type test, at least equal to the requirements
specified in the contract, in lieu of the type test;
– for type tests performed on valve sections, the total number of thyristor levels subjected to
such type tests shall be at least equal to the number of thyristor levels in a valve;
– the valve or valve sections used for type tests shall first pass all production tests. On
completion of the type test programme, the valve or valve sections shall be checked again
for compliance with the production test criteria;
– material for the type tests shall be selected at random;
– the dielectric tests shall be performed in accordance with IEC 60060-1 and IEC 60060-2
where applicable;
– individual tests may be performed in any order.
NOTE Tests involving partial discharge measurement may provide added confidence if performed at the end of the
dielectric type test programme.

– 12 – 61954  IEC:2011
4.4 Test conditions
4.4.1 General
4.4.1.1 Dielectric test objects
Dielectric tests shall be performed on completely assembled valves, whereas some operational
tests may be performed on either complete valves or valve sections. Tests that may be
performed on valve sections are identified in 4.1.
The valve shall be assembled with all auxiliary components except for the valve arrester, if
used. Unless otherwise specified, the valve electronics shall be energized. The cooling and
insulating fluids in particular shall be in a condition that represents service conditions such as
conductivity, except for the flow rate and antifreezing media content, which can be reduced. If
any object or device external to the structure is necessary for proper representation of the
stresses during the test, it shall also be present or simulated in the test. Metallic parts of the
valve structure (or other valves in a MVU) which are not part of the test shall be shorted
together and connected to earth in a manner appropriate to the test in question.
4.4.1.2 Atmospheric correction
When specified in the relevant clause, atmospheric correction shall be applied to the test
voltages in accordance with IEC 60060-1. The reference conditions to which correction shall be
made are the following:
– pressure:
If the insulation coordination of the tested part of the thyristor valve is based on standard rated
withstand voltages according to IEC 60071-1, correction factors are only applied for altitudes
exceeding 1 000 m. Hence if the altitude of the site a at which the equipment will be installed
s
is less than 1 000 m, then the standard atmospheric air pressure (b = 101,3 kPa) shall be
used with no correction for altitude. If a >1 000 m, then the standard procedure according to
s
IEC 60060-1 is used except that the reference atmospheric pressure b is replaced by the
atmospheric pressure corresponding to an altitude of 1 000 m (b ).
1 000m
If the insulation coordination of the tested part of the thyristor valve is not based on standard
rated withstand voltages according to IEC 60071-1, then the standard procedure according to
IEC 60060-1 is used with the reference atmospheric pressure b (b = 101,3 kPa).
0 0
– temperature:
design maximum valve hall air temperature (°C).
– humidity:
design minimum valve hall absolute humidity (g/m ).
The values to be used shall be specified by the supplier.
Where non-standard test levels are defined by this standard, a site air density correction factor
k , defined below shall be applied where stated.
d
The value of k shall be determined from the following expression:
d
b 273 + T
1 2
k = × (1)
d
b 273 + T
2 1
where
b is the laboratory ambient air pressure, expressed in pascals (Pa);
61954  IEC:2011 – 13 –
T is the laboratory ambient air temperature, expressed in degrees Celsius (°C);
b is the standard reference atmosphere of 101,3 kPa (i.e. 1 013 mbar), corrected to the
altitude of the site at which the equipment will be installed;
T is the design maximum valve hall air temperature, expressed in degrees Celsius (°C).
Correction factors should not be applied either to the dielectric tests between valve terminals or
to the long duration dielectric tests whose primary purpose is to check for the internal insulation
and partial discharges.
4.4.1.3 Operational tests
Where possible, a complete thyristor valve should be tested. Otherwise the tests may be
performed on thyristor valve sections. The choice depends mainly upon the thyristor valve
design and the test facilities available. Where tests on the thyristor valve sections are
proposed, the tests specified in this standard are valid for thyristor valve sections containing
five or more series-connected thyristor levels. If tests on thyristor valve sections with fewer
than five thyristor levels are proposed, additional test safety factors shall be agreed upon.
Under no circumstances shall the number of series-connected thyristor levels in a thyristor
valve section be less than three.
Sometimes, operational tests may be performed at a power frequency different from the
service frequency, e.g. 50 Hz instead of 60 Hz. Some operational stresses such as switching
losses or I t of short-circuit current are affected by the actual power frequency during tests.
When this situation occurs, the test conditions shall be reviewed and appropriate changes
made to ensure that the valve stresses are at least as severe as they would be if the tests were
performed at the service frequency.
The coolant shall be in a condition representative of service conditions. Flow and temperature,
in particular, shall be set to the most unfavourable values appropriate to the test in question.
Antifreezing media content should, preferably, be equivalent to the service condition; however,
where this is not practicable, a correction factor agreed between the supplier and the
purchaser shall be applied.
4.4.2 Valve temperature at testing
4.4.2.1 Valve temperature for dielectric tests
Unless specified otherwise, tests shall be performed at room temperature.
4.4.2.2 Valve temperature for operational tests
Unless specified otherwise, tests shall be carried out under the conditions that produce the
highest component temperature that may occur in real operation.
If several components are to be verified by a test, it may be necessary to carry out the same
test under different conditions.
4.4.3 Redundant thyristor levels
4.4.3.1 Dielectric tests
All dielectric tests on a complete valve shall be carried out with redundant thyristor levels short-
circuited, except where otherwise indicated.
4.4.3.2 Operational tests
For operational tests, redundant thyristor levels should not be short-circuited. The test voltages
and circuit impedances used shall be adjusted by means of a scaling factor k .
n
– 14 – 61954  IEC:2011
N
tot
k = (2)
n
N − N
t r
where
N is the total number of series thyristor levels in the test object;
tot
N is the total number of series thyristor levels in the valve;
t
N is the total number of redundant series thyristor levels in the valve.
r
NOTE In thyristor valves with a small number of thyristor levels, where the redundancy is a significant portion of
the total, this may cause certain valve components to be overstressed. As an alternative, it is therefore acceptable
to perform the operational test with redundant thyristor levels short-circuited and without scaling the test voltages
and impedances by k .
n
4.5 Permissible component failures during type testing
Experience in industry shows that, even with the most careful design of valves, it is not
possible to avoid occasional random failures of thyristor level components during service
operation. Even though these failures may be stress-related, they are considered random to
the extent that the cause of failure or the relationship between failure rate and stress cannot be
predicted or is not amenable to precise quantitative definition. Type tests subject valves or
valve sections, within a short time, to multiple stresses that generally correspond to the worst
stresses that can be experienced by the equipment not more than a few times during the life of
the valve. Considering the above, the criteria for successful type testing set out below therefore
permit a small number of thyristor levels to fail during type testing, providing that the failures
are essentially random and do not show any pattern that is indicative of inadequate design.
The valves or valve sections shall be checked before each test, after any preliminary
calibration tests, and again after each type test to determine whether or not any thyristors or
auxiliary components have failed during the test. Failed thyristors or auxiliary components
found at the end of a type test shall be remedied before further testing of a valve.
One thyristor level is permitted to fail due to short-circuiting in any type test. If, following a type
test, one thyristor level has become short-circuited, then the failed level shall be restored and
this type test repeated (see 4.4.1b) in IEC 60700-1, Amendment 1). The total number of
thyristor levels allowed to fail during all tests are given in Table 2.
The distribution of short-circuited l
...