Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC) power transmission - Electrical testing

Ventile von Spannungszwischenkreis-Stromrichtern (VSC) für die Hochspannungsgleichstromübertragung (HGÜ) - Elektrische Prüfung

Valves à convertisseur de source de tension (VSC) pour le transport d’énergie en courant continu à haute tension (CCHT) - Essais électriques

Elektronke za pretvornike napetostnih virov (VSC) za enosmerni visokonapetostni prenos električne energije (HVDC) - Električno preskušanje

General Information

Status
Published
Publication Date
09-Oct-2014
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
10-Oct-2014
Completion Date
10-Oct-2014

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SLOVENSKI STANDARD
SIST EN 62501:2009/A1:2015
01-maj-2015
(OHNWURQNH]DSUHWYRUQLNHQDSHWRVWQLKYLURY 96& ]DHQRVPHUQLYLVRNRQDSHWRVWQL
SUHQRVHOHNWULþQHHQHUJLMH +9'& (OHNWULþQRSUHVNXãDQMH

Voltage sourced converter (VSC) valves for high-voltage direct curent (HVDC) power

transmission - Electrical testing
Spannungsgeführte Stromrichterventile (VSC-Ventile) für die
Hochspannungsgleichstromübertragung (HGÜ) - Elektrische Prüfung
Valves à convertisseur de source de tension (VSC) pour le transport d'énergie en
courant continu à haute tension (CCHT) - Essais électriques
Ta slovenski standard je istoveten z: EN 62501:2009/A1:2014
ICS:
29.200 8VPHUQLNL3UHWYRUQLNL Rectifiers. Convertors.
6WDELOL]LUDQRHOHNWULþQR Stabilized power supply
QDSDMDQMH
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
SIST EN 62501:2009/A1:2015 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 62501:2009/A1:2015
---------------------- Page: 2 ----------------------
SIST EN 62501:2009/A1:2015
EUROPEAN STANDARD EN 62501:2009/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2014
ICS 29.200; 29.240
English Version
Voltage sourced converter (VSC) valves for high-voltage direct
current (HVDC) power transmission - Electrical testing
(IEC 62501:2009/A1:2014)

Valves à convertisseur de source de tension (VSC) pour le Amendment 1: Ventile von Spannungszwischenkreis-

transport d'énergie en courant continu à haute tension Stromrichtern (VSC) für die

(CCHT) - Essais électriques Hochspannungsgleichstromübertragung (HGÜ) -
(CEI 62501:2009/A1:2014) Elektrische Prüfung
(IEC 62501:2009/A1:2014)

This amendment A1 modifies the European Standard EN 62501:2009; it was approved by CENELEC on 2014-09-16. CENELEC members

are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment the status of a

national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the

responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as

the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 62501:2009/A1:2014 E
---------------------- Page: 3 ----------------------
SIST EN 62501:2009/A1:2015
EN 62501:2009/A1:2014 - 2 -
Foreword

The text of document 22F/299/CDV, future IEC 62501:2009/A1, 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 approved by

CENELEC as EN 62501:2009/A1:2014.
The following dates are fixed:
(dop) 2015-06-16
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2017-09-16
standards conflicting with the
document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 62501:2009/A1:2014 was approved by CENELEC as a

European Standard without any modification.
---------------------- Page: 4 ----------------------
SIST EN 62501:2009/A1:2015
- 3 - EN 62501:2009/A1:2014
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
Annex ZA of EN 62501:2009 applies except as follows:
Publication Year Title EN/HD Year
In the Annex ZA of EN 62501:2009 delete from the existing list the following
references:
IEC 60060-1 1989 High-voltage test techniques - HD 588.1 S1 1991
Part 1: General definitions and test
requirements
IEC 60071-1 2006 Insulation co-ordination - EN 60071-1 2006
Part 1: Definitions, principles and rules

In the Annex ZA of EN 62501:2009 Add to the existing list the following references:

IEC 60071 Series Insulation co-ordination EN 60071 Series
IEC 60270 2000 High-voltage test techniques - Partial EN 60270 2001
discharge measurements
---------------------- Page: 5 ----------------------
SIST EN 62501:2009/A1:2015
---------------------- Page: 6 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501
Edition 1.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
A MENDMENT 1
AM ENDEMENT 1
Voltage sourced converter (VSC) valves for high-voltage direct current (HVDC)
power transmission – Electrical testing
Valves à convertisseur de source de tension (VSC) pour le transport d’énergie
en courant continu à haute tension (CCHT) – Essais électriques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX S
ICS 29.200; 29.240 ISBN 978-2-8891-0744-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN 62501:2009/A1:2015
– 2 – IEC 62501:2009/AMD1:2014
© IEC 2014
FOREWORD

This amendment has been prepared by subcommittee 22F: Power electronics for electrical

transmission and distribution systems, of IEC technical committee 22: Power electronic

systems and equipment.
The text of this amendment is based on the following documents:
CDV Report on voting
22F/299/CDV 22F/316A/RVC

Full information on the voting for the approval of this amendment can be found in the report

on voting indicated in the above table.

The committee has decided that the contents of this amendment and the base 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.
_____________
CONTENTS
3.3 Operating states
Replace the subclause title as follows:
3.3 Operating states of converter
4.1.3 Sequence of test
Delete the subclause title.
Add the titles of new Subclause 4.1.8 and new Clause 15 as follows:
4.1.8 Conditions to be considered in determination of type test parameters
15 Tests for dynamic braking valves
Annex A (informative) Overview of VSC topology
---------------------- Page: 8 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501:2009/AMD1:2014 – 3 –
© IEC 2014
Replace the annex title as follows:
Annex A (informative) Overview of VSC converters in HVDC power transmission
Add the titles of new Subclauses A.5.1 to A.5.4 and new Clause A.7 as follows:
A.5.1 General
A.5.2 Modular multi-level converter (MMC)
A.5.3 Cascaded two level converter (CTL)
A.5.4 Terminology for valves of the controllable voltage source type
A.7 Hybrid VSC valves
Annex B (informative) Fault tolerance capability
Replace the annex title as follows:
Annex B (informative) Valve component fault tolerance

Figure A.9 – One possible implementation of a multi-level “voltage source” VSC valve

Replace the figure title as follows:
Figure A.9 - The half-bridge MMC circuit
Add, in the list of figures, the titles of new Figures A.10 to A.13 as follows:
Figure A.10 – The full-bridge MMC circuit
Figure A.11 – The half-bridge CTL circuit
Figure A.12 – Construction terms in MMC valves
Figure A.13 – Construction terms in CTL valves
1 Scope
Add, after the first paragraph, the following two paragraphs:

The scope of this standard includes the electrical type and production tests of dynamic

braking valves which may be used in some HVDC schemes for d.c. overvoltage limitation.

This standard can be used as a guide for testing of STATCOM valves.

Add, at the end of the last sentence of the last paragraph, the words “between the purchaser

and the supplier” so that the last sentence reads as follows:

For other types of valves, the test requirements and acceptance criteria should be agreed

between the purchaser and the supplier.
2 Normative references
Delete from the existing list, the following references:

IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test

requirements

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

---------------------- Page: 9 ----------------------
SIST EN 62501:2009/A1:2015
– 4 – IEC 62501:2009/AMD1:2014
© IEC 2014
Add to the list, the following references:
IEC 60071 (all parts), Insulation co-ordination
IEC 60270:2000, High-voltage test techniques – Partial discharge measurements
3.2 Power semiconductor terms

Replace the existing introductory text, terms and definitions by the following new terms and

definitions:
3.2.1
turn-off semiconductor device

controllable semiconductor device which may be turned on and off by a control signal, for

example an IGBT

NOTE There are several types of turn-off semiconductor devices which can be used in VSC converters for HVDC.

For convenience, the term IGBT is used throughout this standard to refer to the main turn-off semiconductor device.

However, the standard is equally applicable to other types of turn-off semiconductor devices.

3.2.2
insulated gate bipolar transistor
IGBT

turn-off semiconductor device with three terminals: a gate terminal (G) and two load terminals

emitter (E) and collector (C)

NOTE By applying appropriate gate to emitter voltages, the load current can be controlled, i.e. turned on and

turned off.
3.2.3
free-wheeling diode
FWD
power semiconductor device with diode characteristic

NOTE 1 A FWD has two terminals: an anode (A) and a cathode (K). The current through FWDs is in the opposite

direction to the IGBT current.

NOTE 2 FWDs are characterized by the capability to cope with high rates of decrease of current caused by the

switching behaviour of the IGBT.
3.2.4
IGBT-diode pair
arrangement of IGBT and FWD connected in inverse parallel
3.3 Operating states

Replace the existing title, terms and definitions by the following new title, terms and

definitions.
3.3 Operating states of converter
3.3.1
blocking state

condition of the converter, in which a turn-off signal is applied continuously to all IGBTs of the

converter

NOTE Typically, the converter is in the blocking state condition after energization.

---------------------- Page: 10 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501:2009/AMD1:2014 – 5 –
© IEC 2014
3.3.2
de-blocked state

condition of the converter, in which turn-on and turn-off signals are applied repetitively to

IGBTs of the converter
3.3.3
valve protective blocking

means of protecting the valve or converter from excessive electrical stress by the emergency

turn-off of all IGBTs in one or more valves
3.3.4
voltage step level

voltage step caused by switching of a valve or part of a valve during the de-blocked state of

the converter

NOTE For valves of the controllable voltage source type, the voltage step level corresponds to the change of

voltage caused by switching one submodule or cell. For valves of the switch type, the voltage step level

corresponds to the change of voltage caused by switching the complete valve.
3.4 VSC construction terms

Replace the existing terms and definitions by the following new terms and definitions:

3.4.1
VSC phase unit
equipment used to connect the two d.c. busbars to one a.c. terminal
3.4.2
switch type VSC valve
arrangement of IGBT-diode pairs connected in series and arranged to be switched
simultaneously as a single function unit
3.4.3
controllable voltage source type VSC valve

complete controllable voltage source assembly, which is generally connected between one a.c.

terminal and one d.c. terminal
3.4.4
diode valve

semiconductor valve containing only diodes as the main semiconductor devices, which might

be used in some VSC topologies
3.4.5
dynamic braking valve

complete controllable device assembly, which is used to control energy absorption in braking

resistor
3.4.6
valve
VSC valve, dynamic braking valve or diode valve according to the context
3.4.7
submodule

part of a VSC valve comprising controllable switches and diodes connected to a half bridge or

full bridge arrangement, together with their immediate auxiliaries, storage capacitor, if any,

where each controllable switch consists of only one switched valve device connected in series

---------------------- Page: 11 ----------------------
SIST EN 62501:2009/A1:2015
– 6 – IEC 62501:2009/AMD1:2014
© IEC 2014
3.4.8
cell

MMC building block where each switch position consists of more than one IGBT-diode pair

connected in series
NOTE See Figure A.13
3.4.9
VSC valve level
smallest indivisible functional unit of VSC valve

NOTE For any VSC valve in which IGBTs are connected in series and operated simultaneously, one VSC valve

level is one IGBT-diode pair including its auxiliaries (see Figure A.13). For MMC type without IGBT-diode pairs

connected in series one valve level is one submodule together with its auxiliaries (see Figure A.12).

3.4.10
diode valve level

part of a diode valve composed of a diode and associated circuits and components, if any

3.4.11
redundant levels

maximum number of series connected VSC valve levels or diode valve levels in a valve that

may be short-circuited externally or internally without affecting the safe operation of the valve

as demonstrated by type tests, and which if and when exceeded, would require shutdown of

the valve to replace the failed levels or acceptance of increased risk of failures

NOTE In valve designs such as the cascaded two level converter, which contain two or more conduction paths

within each cell and have series-connected VSC valve levels in each path, redundant levels shall be counted only

in one conduction path in each cell.
3.4.12
dynamic braking valve level

part of a dynamic braking valve comprising a controllable switch and an associated diode, or

controllable switches and diodes connected in parallel, or controllable switches and diodes

connected to a half bridge arrangement, together with their immediate auxiliaries, storage

capacitor, if any
3.5.1 valve structure
Replace the existing definition by the following new definition:

structural components of a valve, required in order to physically support the valve modules

3.5.2 valve support
Delete the note.
3.5.4 valve section
Replace the definition by the following new definition and notes:

electrical assembly defined for test purposes, comprising a number of valve levels and other

components, which exhibits pro-rated electrical properties of a complete valve

NOTE 1 For valves of controllable voltage source type the valve section shall include cell or submodule d.c.

capacitor in addition to VSC valve levels.

NOTE 2 The minimum number of VSC or diode valve levels allowed in a valve section is defined along with the

requirements of each test.
3.5.5 valve base electronics
Replace the definition by the following new definition.
---------------------- Page: 12 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501:2009/AMD1:2014 – 7 –
© IEC 2014

electronic unit, at earth potential, providing the electrical to optical conversion between the

converter control system and the VSC valves
4.1.3 Sequence of test
Delete the entire subclause, including the title, text and note.
4.1.4 Test procedure
Replace the existing sentence with the following new text:

The tests shall be performed in accordance with IEC 60060, where applicable with due

account for IEC 60071 (all parts). Partial discharge measurements shall be performed in

accordance with IEC 60270.
4.1.5 Ambient temperature for testing
Replace the text of this subclause with the following sentence:

The tests shall be performed at the prevailing ambient temperature of the test facility, unless

otherwise specified.
4.1.6 Frequency for testing
Add, at the end of the subclause, the following note:

NOTE Guidance on the worst service conditions can be found in CIGRÉ Technical Brochure No. 447.

Add, after 4.1.7, a new subclause as follows:
4.1.8 Conditions to be considered in determination of type test parameters

Type test parameters should be determined based on the worst operating and fault conditions

to which the valve can be subjected, according to system studies. Guidance on the conditions

can be found in CIGRÉ Technical Brochure No. 447.
4.2 Atmospheric correction factor

Insert, between the last dashed item and the last paragraph , the following new paragraph:

Realistic worst case combinations of temperature and humidity which can occur in practice

shall be used for atmospheric correction.
4.4.2 Criteria applicable to valve levels

Replace, in this entire subclause the words “short-circuited” by “short or open circuited”

Delete, in the last sentence of item f), the word “total”, so that the sentence reads as follows:

If the number of such levels exceeds 3 %, then the nature of the faults and their cause shall

be reviewed and additional action, if any, agreed between purchaser and supplier.

Table 2 – Valve level faults permitted during type tests
Replace the words “short-circuited” by “short or open circuited”.
---------------------- Page: 13 ----------------------
SIST EN 62501:2009/A1:2015
– 8 – IEC 62501:2009/AMD1:2014
© IEC 2014
6.2 Test object

Replace in the third sentence of the first paragraph the words “VSC /diode” by “valve”.

6.4 Maximum continuous operating duty test

Delete in the fifth paragraph, the last sentence “The coolant temperature shall be not less …

temperatures in service” so that the paragraph now ends with “shall be representative of that

used in service”.
6.6 Minimum d.c. voltage test

Correct in the notation for the letter symbol U , the word “require” to “required”.

7.3.1 Valve support d.c. voltage test

Replace, in the second sentence of the first paragraph, the words “in approximately 10 s” by

“as fast as possible”.

Replace the existing note and the text below the note with the following new notes and text:

NOTE 1 Where possible the test voltage should be increased from 50 % to the maximum voltage level within

approximately 10 s. A longer time may be used; however, this may overstress the test object.

NOTE 2 If an increasing trend in the magnitude or rate of partial discharge is observed, the test duration may be

extended by mutual agreement between the purchaser and supplier.
The test shall then be repeated with the voltage of opposite polarity.

Prior to the test and before repeating the test with voltage of opposite polarity the valve

support may be short-circuited and earthed for a duration of several hours. The same

procedure may be followed at the end of d.c. voltage test.

The valve support d.c. test voltage U shall be determined in accordance with the following:

tds
1 min. test
U =±U ⋅k ⋅k
tds dmS1 3 t
3 h test
U =±U ⋅k
tds dmS2 3
where

U is the maximum of 1 s average value of voltage appearing across the valve support

dmS1
as determined by the insulation coordination study;

U is the maximum value of the d.c. component of the steady-state operating voltage

dmS2
appearing across the valve support;
k is a test safety factor;
k = 1,1;
k is the atmospheric correction factor according to 4.2.
7.3.2 Valve support a.c. voltage test
Replace the first paragraph as follows:
---------------------- Page: 14 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501:2009/AMD1:2014 – 9 –
© IEC 2014

To perform the test, the two main terminals of the valve shall be connected together, and the

a.c. test voltage then applied between the two main terminals thus connected and earth.

Starting from a voltage not higher than 50 % of the maximum test voltage, the voltage shall be

raised to the specified 1 min test voltage, kept constant for 1 min, reduced to the specified

30 min test voltage, kept constant for 30 min and then reduced to zero.

Before the end of the 30 min test the level of partial discharge shall be monitored and

recorded over a 1 min period. If the value of partial discharge is below 200 pC, the design

may be accepted unconditionally. If the value of partial discharge exceeds 200 pC, the test

results shall be evaluated.

Delete in the list of notations, the second and the third symbols and their meanings i.e."U

tas1
is the 1 min test voltage" and "U is the 30 min test voltage".
tas2
8.3.1 MVU d.c. voltage test to earth

Replace, in the second paragraph, the words “in approximately 10 s” by “as fast as possible”.

Add, after the second paragraph the following new note and renumber the existing note as

“NOTE 2”.

NOTE 1 Where possible the test voltage should be increased from 50 % to the maximum voltage level within

approximately 10 s. A longer time may be used; however, this may overstress the test object.

Replace the last two paragraphs including the list of notations, from “Prior to the test, the

MVU terminal…” to “k = 1,0 for the 3 h test. ” by the following new text:

Prior to the test and before repeating the test with voltage of opposite polarity the MVU

terminals may be short-circuited together and earthed for a duration of several hours. The

same procedure may be followed at the end of d.c. voltage test.

The MVU d.c. test voltage U shall be determined in accordance with the following:

tdm
1 min. test
U =±U ⋅k ⋅k
tdm dmm1 5 t
3 h test
U =±U ⋅k
tdm dmm2 5
where

U is the maximum of 1 s average value of voltage appearing between the high-voltage

dmm1
terminal of the MVU and earth;

U is the maximum value of the d.c. component of the steady-state operating voltage

dmm2
appearing between the high-voltage terminal of the MVU and earth;
k is a test safety factor;
k = 1,1;
k is the atmospheric correction factor according to 4.2.
8.3.2 MVU a.c. voltage test

Replace the fourth paragraph “During the specified 30 min. test, the level …” by the following

new text:
---------------------- Page: 15 ----------------------
SIST EN 62501:2009/A1:2015
– 10 – IEC 62501:2009/AMD1:2014
© IEC 2014

Before the end of the 30 min test, the level of partial discharge shall be monitored and

recorded over a 1 min. period. If the value of partial discharge is below 200 pC, the design

may be accepted unconditionally. If the value of partial discharge exceeds 200 pC, the test

results shall be evaluated.
9.2 Test object

Replace the third sentence of the first paragraph with the following new sentence:

The test valve or valve section shall be assembled with all auxiliary components except for

the valve arrester if provided.
9.3.1 Valve a.c. – d.c. voltage test
Replace the entire text of this subclause by the following new text:

This test consists of a short-duration test and a long-duration test. The short-duration test

reproduces the composite a.c. – d.c. voltage resulting from certain converter or system faults.

In this test, a capacitor can be used in conjunction with an a.c. test voltage source to produce

a composite a.c. – d.c. voltage waveform. Depending on the converter topology, the capacitor

could be an integral part of the valve, or it could be a separate item (part of the test circuit,

not part of the test object).

Alternatively, a separate d.c. voltage source could be used to substitute the capacitor.

Starting from a voltage not higher than 50 % of the maximum test voltage, the voltage shall be

raised to the specified 10 s test level as fast as possible, reduced to the specified 3 h test

voltage, kept constant for 3 h and then reduced to zero.

For a.c. PD (partial discharge) measurement the peak value of the periodic partial discharge

recorded during the last minute of the 3 h test shall be less than 200 pC, provided that the

components which are sensitive to partial discharge in the valve have been separately tested.

For d.c PD measurement the recording time shall be the last hour of the 3 h test. The number

of pulses exceeding 300 pC shall not exceed 15 per minute, averaged over the record period.

Of these, no more than seven pulses per minute shall exceed 500 pC, no more than three

pulses per minute shall exceed 1 000 pC and no more than one pulse per minute shall exceed

2 000 pC.

NOTE 1 Performing the valve a.c. – d.c. voltage test presents considerable practical difficulties on valves of the

“controllable voltage source” type because of the high current drawn by the in-built capacitance during start-up and

the slow discharge rate of the capacitor at the end of the first part of the test. For this reason, it may be necessary

to modify the test procedure when testing valves of this type. Alternative test methods to be considered include the

temporary substitution of a special test capacitor with reduced capacitance but the same physical size, or the pre-

charging of the cell or submodule d.c. capacitor from a separate source before commencing the test.

NOTE 2 Where possible the test voltage should be increased from 50 % to the maximum voltage level within

approximately 10 s. A longer time may be used; however, this overstresses the test object.

NOTE 3 If an increasing trend in the rate or magnitude of partial discharge is observed, the test duration may be

extended by mutual agreement between the purchaser and supplier.

NOTE 4 It may be necessary to disable gate electronics or other auxiliary circuits in this test, or provide

independent means for powering them, in order to prevent interference with partial discharge measurement, for

example, from gate unit power supply circuits.

NOTE 5 In the event that it is not possible to disable gate electronics or other auxiliary circuits in this test and

interference can be proven to be caused by electronics circuit then this interference may be deducted from

measurement.

NOTE 6 The use of a capacitor instead of a d.c. source in the test circuit should be mutually agreed by

manufacturer and purchaser as the test voltage is higher than actual value.
---------------------- Page: 16 ----------------------
SIST EN 62501:2009/A1:2015
IEC 62501:2009/AMD1:2014 – 11 –
© IEC 2014

The valve test voltages have a sinusoidal waveshape superimposed on a d.c. level.

The valve 10 s test voltage U shall be determined in accordance with the following:

tv1
U =(k ⋅U ⋅sin(2πft)+ U )⋅k ⋅k
tv1 c1 tac1 tdc1 o 9
where

U is the peak value of maximum transient a.c. component over-voltage across valve. The

ac1

limiting effect of valve arrester or pole arrester can be taken into account to derive the

over-voltage in service condition;

U is the maximum transient d.c. component over-voltage across valve. The limiting effect

dc1

of valve arrester or pole arrester can be taken into account to derive the over-voltage

in service condition;

k is the voltage step overshoot factor related to one output voltage step of the converter,

under the condition consistent with that used to define U . For a MMC or CTL type

ac1

converter the voltage step overshoot factor relates to the overshoot factor of one cell

or submodule;
k is a test scaling factor according to 4.3.2;
k is a test safety factor;
k = 1,10;
f is the test frequency (50 Hz or 60 Hz depending on test facilities).

The valve 3 h test voltage U shall be determined in accordance with the following:

tv2
U = U + U
tv2 tac2 tdc2
2⋅U ⋅sin(2πft)
max−cont
U = ⋅k ⋅k ⋅k
tac2 c2 o 10
U = U ⋅ k ⋅ k
tdc2 dmax o 10
where
U is the maximum steady-state phase-to-phase voltage on the a.c. system or the
max-cont

valve side of the transformer, if a converter transformer is used in between a.c.

system and converters;

U is the maximum value of the d.c. component of the steady-state operating voltage

dmax
of the d.c. system;

k is the voltage step overshoot factor related to one output voltage step of the

converter, under the condition consistent with that used to defin
...

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