Components for low-voltage surge protective devices - Part 311: Performance requirements and test circuits and methods for gas discharge tubes (GDT)

This part of IEC 61643 is applicable to gas discharge tubes (GDT) used for overvoltage protection in telecommunications, signalling and low-voltage power distribution networks with nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c..They are defined as a gap, or several gaps with two or three metal electrodes hermetically sealed so that gas mixture and pressure are under control. They are designed to protect apparatus or personnel, or both, from high transient voltages. This standard contains a series of test criteria, test methods and test circuits for determining the electrical characteristics of GDTs having two or three electrodes. This standard does not specify requirements applicable to complete surge protective devices, nor does it specify total requirements for GDTs employed within electronic devices, where precise coordination between GDT performance and surge protective device withstand capability is highly critical. This part of IEC 61643 - does not deal with mountings and their effect on GDT characteristics. Characteristics given apply solely to GDTs mounted in the ways described for the tests; - does not deal with mechanical dimensions; - does not deal with quality assurance requirements; - may not be sufficient for GDTs used on high-frequency (>30 MHz); - does not deal with electrostatic voltages; - does not deal with hybrid overvoltage protection components or composite GDT devices.

Bauelemente für Überspannungsschutzgeräte für Niederspannung - Teil 311: Leistungsanforderungen sowie Prüfschaltungen und -verfahren für Gasentladungsableiter (ÜsAG)

Composants pour parafoudres basse tension - Partie 311: Circuits et méthodes d'essai pour tubes à décharge de gaz

La CEI 61643-311:2013 est applicable aux tubes à décharge de gaz (TDG) utilisés pour la protection contre les surtensions des réseaux de télécommunications, de signaux et de distribution basse tension, dont les tensions nominales de réseau sont inférieures ou égales à 1 000 V (valeurs efficaces) c.a. et 1 500 V c.c. Ils sont définis comme un éclateur ou des éclateurs avec deux ou trois électrodes métalliques hermétiquement scellées de sorte que le mélange et la pression de gaz soient sous contrôle. Ils sont conçus pour protéger des matériels ou des personnes, ou les deux, contre des surtensions transitoires élevées. La présente norme contient une série de critères d'essai, de méthodes d'essai et de circuits d'essai destinés à déterminer les caractéristiques électriques des TDG comportant deux ou trois électrodes. La présente norme ne traite pas des exigences applicables aux parafoudres complets, ni de la totalité des exigences relatives aux TDG utilisés dans les dispositifs électroniques, où une coordination précise entre les performances des TDG et la résistance des parafoudres aux surtensions est primordiale. Cette deuxième édition de la CEI 61643-311 annule et remplace la première édition publiée en 2001 dont elle constitue une révision technique. Les changements spécifiques par rapport à l'édition précédente sont: l'ajout des valeurs de performance. Mots clés: tubes à décharge de gaz (TDG), protection contre les surtensions des réseaux de télécommunications, de signaux et de distribution basse tension, tensions nominales sont inférieures ou égales à 1 000 V (valeurs efficaces) c.a. et 1 500 V c.c

Sestavni deli za nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 311. del: Zahtevane lastnosti, preskusni tokokrogi in metode preskušanja plinskih odvodnikov (IEC 61643-311:2013)

Ta del standarda IEC 61643 se uporablja za s plinom polnjene cevi (GDT), ki se uporabljajo za prenapetostno zaščito pri telekomunikacijah, signaliziranju in nizkonapetostnih razdelilnih omrežjih z nazivnimi sistemskimi napetostmi do 1000 V (efektivne izmenične napetosti) izmenične napetosti in 1500 V enosmerne napetosti. Določene so kot reža ali več rež z dvema ali tremi nepredušno zatesnjenimi kovinskimi elektrodami, tako sta zmes plinov in tlak pod nadzorom. Zasnovane so tako, da ščitijo aparat ali osebje ali oboje pred visokimi tranzientnimi napetostmi. Ta standard vsebuje niz preskusnih meril, preskusnih metod in preskusnih tokokrogov za ugotavljanje električnih značilnosti s plinom polnjenih cevi z dvema ali tremi elektrodami. Ta standard ne določa zahtev, ki se uporabljajo za celotne prenapetostne zaščitne naprave, niti ne določa skupnih zahtev za s plinom polnjene cevi, ki se uporabljajo znotraj elektronskih naprav, kjer je natančna koordinacija med delovanjem s plinom polnjenih cevi in odpornostjo prenapetostne zaščitne naprave izjemno kritična. Ta del standarda IEC 61643 – ne obravnava elementov za pritrditev in njihovega vpliva na značilnosti s plinom polnjenih cevi. Navedene značilnosti se uporabljajo izključno za s plinom polnjene cevi, ki so pritrjene na načine, opisane za preskuse; – ne obravnava mehanskih dimenzij; – ne obravnava zahtev za zagotavljanje kakovosti; – morda ne zadostuje za s plinom polnjene cevi, ki se uporabljajo pri visoki frekvenci (>30 MHz); – ne obravnava elektrostatičnih napetosti; –ne obravnava komponent hibridne prenapetostne zaščite ali sestavljenih naprav s cevmi, polnjenimi s plinom.

General Information

Status
Published
Public Enquiry End Date
30-Mar-2010
Publication Date
23-Sep-2013
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
27-Aug-2013
Due Date
01-Nov-2013
Completion Date
24-Sep-2013

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SLOVENSKI STANDARD
SIST EN 61643-311:2013
01-oktober-2013
1DGRPHãþD
SIST EN 61643-311:2005
6HVWDYQLGHOL]DQL]NRQDSHWRVWQHQDSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL

GHO=DKWHYDQHODVWQRVWLSUHVNXVQLWRNRNURJLLQPHWRGHSUHVNXãDQMDSOLQVNLK

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Components for low-voltage surge protective devices - Part 311: Performance
requirements and test circuits and methods for gas discharge tubes (GDT)

Composants pour parafoudres basse tension - Partie 311: Circuits et méthodes d'essai

pour tubes à décharge de gaz
Ta slovenski standard je istoveten z: EN 61643-311:2013
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
29.240.10 Transformatorske postaje. Substations. Surge arresters
Prenapetostni odvodniki
SIST EN 61643-311:2013 en,fr

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

---------------------- Page: 1 ----------------------
SIST EN 61643-311:2013
---------------------- Page: 2 ----------------------
SIST EN 61643-311:2013
EUROPEAN STANDARD
EN 61643-311
NORME EUROPÉENNE
August 2013
EUROPÄISCHE NORM
ICS 31.100; 33.040.99 Supersedes EN 61643-311:2001 (partially)
English version
Components for low-voltage surge protective devices -
Part 311: Performance requirements and test circuits for gas discharge
tubes (GDT)
(IEC 61643-311:2013)
Composants pour parafoudres basse Bauelemente für
tension - Überspannungsschutzgeräte für
Partie 311: Exigences de performance et Niederspannung -
circuits d'essai pour tubes à décharge de Teil 311: Leistungsanforderungen sowie
gaz (TDG) Prüfschaltungen und -verfahren für
(CEI 61643-311:2013) Gasentladungsableiter (ÜsAG)
(IEC 61643-311:2013)

This European Standard was approved by CENELEC on 2013-05-16. 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 CEN-CENELEC Management Centre 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 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.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61643-311:2013 E
---------------------- Page: 3 ----------------------
SIST EN 61643-311:2013
EN 61643-311:2013 - 2 -
Foreword

The text of document 37B/113/FDIS, future edition 2 of IEC 61643-311, prepared by SC 37B, "Specific

components for surge arresters and surge protective devices", of IEC TC 37, "Surge arresters" was

submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61643-311:2013.

The following dates are fixed:
• latest date by which the document has (dop) 2014-02-16
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2016-05-16
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document partially supersedes EN 61643-311:2001.

EN 61643-311:2013 includes the following significant technical changes with respect to

EN 61643-311:2001:
- addition of performance values.

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 61643-311:2013 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60364-5-51:2005 NOTE Harmonised as HD 60364-5-51:2009 (modified).
IEC 61180-1:1992 NOTE Harmonised as EN 61180-1:1994 (not modified).
IEC 61643-312 NOTE Harmonised as EN 61643-312.
IEC 61643-11:2011 NOTE Harmonised as EN 61643-11:2012 (modified).
IEC 61643-21:2000 NOTE Harmonised as EN 61643-21:2001 (not modified)
+ A1:2008 + A1:2009 (modified)
---------------------- Page: 4 ----------------------
SIST EN 61643-311:2013
- 3 - EN 61643-311:2013
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

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 60068-2-1 2007 Environmental testing - EN 60068-2-1 2007
Part 2-1: Tests - Test A: Cold
IEC 60068-2-20 2008 Environmental testing - EN 60068-2-20 2008
Part 2-20: Tests - Test T: Test methods for
solderability and resistance to soldering heat
of devices with leads
IEC 60068-2-21 2006 Environmental testing - EN 60068-2-21 2006
+ corr. January 2012 Part 2-21: Tests - Test U: Robustness of
terminations and integral mounting devices
IEC 61000-4-5 2005 Electromagnetic compatibility (EMC) - EN 61000-4-5 2006
+ corr. October 2009 Part 4-5: Testing and measurement
techniques - Surge immunity test
ITU-T 2011 Resistibility of telecommunication equipment - -
Recommendation installed in a telecommunications centre to
K.20 overvoltages and overcurrents
---------------------- Page: 5 ----------------------
SIST EN 61643-311:2013
---------------------- Page: 6 ----------------------
SIST EN 61643-311:2013
IEC 61643-311
Edition 2.0 2013-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Components for low-voltage surge protective devices –
Part 311: Performance requirements and test circuits for gas discharge tubes
(GDT)
Composants pour parafoudres basse tension –
Partie 311: Exigences de performance et circuits d’essai pour tubes à décharge
de gaz (TDG)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 31.100; 33.040.99 ISBN 978-2-83220-678-2

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 61643-311:2013
– 2 – 61643-311 © IEC:2013
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope ............................................................................................................................... 6

2 Normative references ....................................................................................................... 6

3 Terms, definitions and symbols ........................................................................................ 7

3.1 Terms and definitions .............................................................................................. 7

3.2 Symbols ................................................................................................................ 10

4 Service conditions .......................................................................................................... 10

4.1 Low temperature ................................................................................................... 10

4.2 Air pressure and altitude ....................................................................................... 10

4.3 Ambient temperature ............................................................................................. 10

4.4 Relative humidity ................................................................................................... 11

5 Mechanical requirements and materials .......................................................................... 11

5.1 Robustness of terminations ................................................................................... 11

5.2 Solderability .......................................................................................................... 11

5.3 Radiation ............................................................................................................... 11

5.4 Marking ................................................................................................................. 11

6 General .......................................................................................................................... 11

6.1 Failure rates .......................................................................................................... 11

6.2 Standard atmospheric conditions ........................................................................... 11

7 Electrical requirements ................................................................................................... 12

7.1 General ................................................................................................................. 12

7.2 Initial values .......................................................................................................... 12

7.2.1 Sparkover voltages .................................................................................... 12

7.2.2 Insulation resistance .................................................................................. 13

7.2.3 Capacitance .............................................................................................. 13

7.2.4 Transverse voltage .................................................................................... 13

7.2.5 DC holdover .............................................................................................. 13

7.3 Requirements after application of load................................................................... 13

7.3.1 General ..................................................................................................... 13

7.3.2 Sparkover voltages .................................................................................... 14

7.3.3 Insulation resistance .................................................................................. 14

7.3.4 AC follow current ....................................................................................... 14

7.3.5 Fail-short (Failsafe) ................................................................................... 15

8 Test and measurement procedures and circuits .............................................................. 15

8.1 DC sparkover voltage ............................................................................................ 15

8.2 Impulse sparkover voltage ..................................................................................... 16

8.3 Insulation resistance ............................................................................................. 16

8.4 Capacitance .......................................................................................................... 16

8.5 Glow-to-arc transition current, glow voltage, arc voltage ........................................ 16

8.6 Transverse voltage ................................................................................................ 18

8.7 DC holdover voltage .............................................................................................. 19

8.7.1 General ..................................................................................................... 19

8.7.2 DC holdover voltage values ....................................................................... 21

8.8 Requirements for current-carrying capacity ........................................................... 22

8.8.1 General ..................................................................................................... 22

---------------------- Page: 8 ----------------------
SIST EN 61643-311:2013
61643-311 © IEC:2013 – 3 –

8.8.2 Nominal alternating discharge current ........................................................ 22

8.8.3 Nominal impulse discharge current, waveshape 8/20 ................................. 23

8.8.4 Life test with impulse currents, waveshape 10/1 000 ................................. 24

8.8.5 AC follow current ....................................................................................... 24

8.9 Fail-short (failsafe) ................................................................................................ 25

Bibliography .......................................................................................................................... 27

Figure 1 – Voltage and current characteristics of a GDT ......................................................... 8

Figure 2 – Symbol for a two-electrode GDT ......................................................................... 10

Figure 3 – Symbol for a three-electrode GDT ....................................................................... 10

Figure 4 – Circuit for d.c. sparkover voltage test at 100 V/s .................................................. 15

Figure 5 – Circuit for impulse sparkover voltage at 1 000 V/µs .............................................. 16

Figure 6 – Test circuit for glow-to-arc transition current, glow voltage and arc voltage ......... 17

Figure 7 – Voltage-current characteristic of a typical GDT, suitable for measuring for

example the glow-to-arc transition current, glow voltage, and arc voltage ............................. 18

Figure 8 – Test circuit for transverse voltage ........................................................................ 19

Figure 9 – Test circuit for dc holdover voltage, two-electrode GDTs ...................................... 20

Figure 10 – Test circuit for dc holdover voltage, three-electrode GDTs ................................. 20

Figure 11 – Circuit for nominal alternating discharge current, two-electrode GDTs ................ 23

Figure 12 – Circuit for nominal alternating discharge current, three-electrode GDTs ............. 23

Figure 13 – Circuit for nominal impulse discharge current, two-electrode GDTs .................... 23

Figure 14 – Circuit for nominal impulse discharge current, three-electrode GDTs .................. 23

Figure 15 – Circuit for life test with impulse current, two-electrode GDTs .............................. 24

Figure 16 – Circuit for life test with impulse current, three-electrode GDTs ........................... 24

Figure 17 – Test circuit for alternating follow current ............................................................. 25

Figure 18 – Test circuit for fail-short (failsafe), two-electrode GDTs ...................................... 26

Figure 19 – Test circuit for fail-short (failsafe), three-electrode GDTs ................................... 26

Table 1 – DC and impulse sparkover voltage requirements, initial ......................................... 12

Table 2 – Values of sparkover voltages after the tests of Table 5 .......................................... 14

Table 3 – Values for different d.c. holdover voltage tests for two-electrode GDTs ................. 21

Table 4 – Values for different d.c. holdover voltage tests for three-electrode GDTs ............... 21

Table 5 – Different classes of current-carrying capacity ........................................................ 22

---------------------- Page: 9 ----------------------
SIST EN 61643-311:2013
– 4 – 61643-311 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPONENTS FOR LOW-VOLTAGE
SURGE PROTECTIVE DEVICES –
Part 311: Performance requirements and
test circuits for gas discharge tubes (GDT)
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 61643-311 has been prepared by subcommittee 37B: Specific

components for surge arresters and surge protective devices, of IEC technical committee 37:

Surge arresters.

This second edition of IEC 61643-311 cancels and replaces the first edition published in 2001.

It constitutes a technical revision.
Specific changes with respect to the previous edition are:
– Addition of performance values.
---------------------- Page: 10 ----------------------
SIST EN 61643-311:2013
61643-311 © IEC:2013 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
37B/113/FDIS 37B/118/RVD

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

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 61643 series, under the general title Components for low-voltage

surge protective devices can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 11 ----------------------
SIST EN 61643-311:2013
– 6 – 61643-311 © IEC:2013
COMPONENTS FOR LOW-VOLTAGE
SURGE PROTECTIVE DEVICES –
Part 311: Performance requirements and
test circuits for gas discharge tubes (GDT)
1 Scope

This part of IEC 61643 is applicable to gas discharge tubes (GDT) used for overvoltage

protection in telecommunications, signalling and low-voltage power distribution networks with

nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c..They are defined as a

gap, or several gaps with two or three metal electrodes hermetically sealed so that gas

mixture and pressure are under control. They are designed to protect apparatus or personnel,

or both, from high transient voltages. This standard contains a series of test criteria, test

methods and test circuits for determining the electrical characteristics of GDTs having two or

three electrodes. This standard does not specify requirements applicable to complete surge

protective devices, nor does it specify total requirements for GDTs employed within electronic

devices, where precise coordination between GDT performance and surge protective device

withstand capability is highly critical.
This part of IEC 61643

– does not deal with mountings and their effect on GDT characteristics. Characteristics

given apply solely to GDTs mounted in the ways described for the tests;
– does not deal with mechanical dimensions;
– does not deal with quality assurance requirements;
– may not be sufficient for GDTs used on high-frequency (>30 MHz);
– does not deal with electrostatic voltages;

– does not deal with hybrid overvoltage protection components or composite GDT devices.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-2-1:2007, Environmental testing – Part 2: Tests. Tests A: Cold

IEC 60068-2-20:2008, Environmental testing – Part 2: Tests. Test T: Test methods for

solderability and resistance to soldering heat of devices with leads

IEC 60068-2-21:2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of

terminations and integral mounting devices

IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement

techniques – Section 5: Surge immunity test

ITU-T Recommendation K.20:2011, Resistibility of telecommunication equipment installed in a

telecommunications centre to overvoltages and overcurrents
---------------------- Page: 12 ----------------------
SIST EN 61643-311:2013
61643-311 © IEC:2013 – 7 –
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply
3.1.1
arc current

current that flows after sparkover when the circuit impedance allows a current to flow that

exceeds the glow-to-arc transition current
3.1.2
arc voltage
arc mode voltage
voltage drop across the GDT during arc current flow
Note 1 to entry: See Figure 1a region A.
3.1.3
arc-to-glow transition current
current required for the GDT to pass from the arc mode into the glow mode
3.1.4
current turn-off time

time required for the GDT to restore itself to a non-conducting state following a period of

conduction.

Note 1 to entry: This applies only to a condition where the GDT is exposed to a continuous d.c. potential (see d.c.

holdover).
3.1.5
d.c. sparkover voltage
d.c. breakdown voltage

voltage at which the GDT transitions from a high-impedance off to a conduction state when a

slowly rising d.c. voltage up to 2 kV/s is applied

Note 1 to entry: The rate of rise for d.c. sparkover voltage measurements is usually equal or less 2 000 V/s.

3.1.6
d.c. holdover

state in which a GDT continues to conduct after it is subjected to an impulse sufficient to

cause breakdown.

Note 1 to entry: In applications where a d.c. voltage exists on a line. Factors that affect the time required to

recover from the conducting state (current turn-off time) include the d.c. voltage and the d.c. current

3.1.7
d.c. holdover voltage

maximum d.c. voltage across the terminals of a gas discharge tube under which it may be

expected to clear and to return to the high-impedance state after the passage of a surge,

under specified circuit conditions
3.1.8
discharge current
current that flows through a GDT after sparkover occurs

Note 1 to entry: In the event that the current passing through the GDT is alternating current, it will be r.m.s. value.

In instances where the current passing through the GDT is an impulse current, the value will be the peak value.

---------------------- Page: 13 ----------------------
SIST EN 61643-311:2013
– 8 – 61643-311 © IEC:2013
3.1.9
discharge voltage
residual voltage of an arrester

peak value of voltage that appears across the terminals of a GDT during the passage of GDT

discharge current
3.1.10
discharge voltage current characteristic
V/I characteristic

variation of peak values of discharge voltage with respect to GDT discharge current

Figure 1c Figure 1a
Figure 1b
IEC 527/13
Legend
V spark-over voltage V arc voltage G glow mode range
s a
V glow voltage V extinction voltage A arc mode range
gl e

Figure 1a – Voltage at a GDT as a function of time when limiting a sinusoidal voltage

Figure 1b – Current at a GDT as a function of time when limiting a sinusoidal voltage

Figure 1c – V/I characteristic of a GDT obtained by combining the graphs of voltage and current

Figure 1 – Voltage and current characteristics of a GDT
3.1.11
extinction voltage
voltage at which discharge (current flow) ceases
3.1.12
fail-short
failsafe
thermally-activated external shorting mechanism
---------------------- Page: 14 ----------------------
SIST EN 61643-311:2013
61643-311 © IEC:2013 – 9 –
3.1.13
follow on current
current that the GDT conducts from a connected power source after sparkover

Note 1 to entry: The GDT is expected to extinguish after sparkover to avoid overheating

3.1.14
gas discharge tube
GDT

gap, or several gaps with two or three metal electrodes hermetically sealed so that gas

mixture and pressure are under control, designed to protect apparatus or personnel, or both,

from high transient voltages
3.1.15
glow current
glow mode current

current that flows after breakdown when the circuit impedance limits the follow current to a

value less than the glow-to-arc transition current
Note 1 to entry: See Figure 1a region G.
3.1.16
glow-to-arc transition current
current required for the GDT to pass from the glow mode into the arc mode
Note 1 to entry: See Figure 1a region G.
3.1.17
glow voltage
glow mode voltage
peak value of voltage drop across the GDT when a glow current is flowing
Note 1 to entry: See Figure 1a region G.
3.1.18
impulse sparkover voltage

highest value of voltage attained by an impulse of a designated voltage rate-of-rise and

polarity applied across the terminals of a GDT prior to the flow of the discharge current

3.1.19
impulse waveshape

outline of an electrical surge designated as x/y having a rise time of x µs and a decay time to

half value of y µs
3.1.20
nominal alternating discharge current
current which the GDT is designed to conduct for a defined time
Note 1 to entry: For currents with a frequency of 15 Hz to 62 Hz.
3.1.21
nominal d.c. sparkover voltage

voltage specified by the manufacturer to indicate the target value of sparkover voltages of a

particular type of GDT products

Note 1 to entry: The nominal value is generally a rounded number such as: 75 V, 90 V, 150 V, 200 V, 230 V,

250 V, 300 V, 350 V, 420 V, 500 V, 600 V, 800 V, 1 000 V, 1 200 V, 1 400 V, 1 800 V, 2 100 V, 2 700 V, 3 000 V,

3 600 V, 4 000 V and 4 500 V.
Note 2 to entry: Values in between
...

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