IEC 62848-2:2019

IEC 62848-2 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
Railway applications – DC surge arresters and voltage limiting devices –
Part 2: Voltage limiting devices

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IEC 62848-2 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
Railway applications – DC surge arresters and voltage limiting devices –

Part 2: Voltage limiting devices

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 45.060.01 ISBN 978-2-8322-6884-1

– 2 – IEC 62848-2:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Classes of VLD . 9
5 Characteristics and requirements of the VLDs . 10
5.1 Marking . 10
5.2 Service requirements . 11
5.2.1 Normal outdoor service conditions . 11
5.2.2 Normal indoor service conditions . 11
5.2.3 Abnormal service conditions . 11
5.3 General characteristics . 12
5.4 Minimum requirements . 12
5.4.1 Response time . 12
5.4.2 Additional requirements for VLDs of Class 1 . 12
5.4.3 Additional requirements for VLDs of Classes 3 and 4 . 12
5.5 Electrical characteristics and thermal rating . 12
5.6 Protection of VLDs against lightning. 13
5.7 Command and control (Classes 3 and 4 only) . 13
5.7.1 Local control . 13
5.7.2 Remote signalling . 13
5.7.3 Operation and alarm recordings . 14
6 Type tests . 14
6.1 General . 14
6.2 Nominal triggering voltage U and non-triggering voltage U . 15
Tn W
6.2.1 Procedure for welding shut spark gap VLDs (Class 1) . 15
6.2.2 Procedure for thyristor type VLDs (Class2) . 16
6.2.3 Procedure for mechanical switching VLDs and for combined thyristors
with mechanical switching devices VLDs (Class 3 and Class 4) . 17
6.3 Leakage current . 17
6.4 DC current withstand . 18
6.4.1 General . 18
6.4.2 DC rated current test . 18
6.4.3 Short time withstand current test . 19
6.5 AC current withstand characteristics (optional). 20
6.6 Response time characteristics . 20
6.6.1 Response time for DC voltage . 20
6.6.2 Response time for combined AC-DC voltage . 22
6.7 Lightning current impulse withstand characteristics for VLDs exposed to
direct lightning strikes . 24
6.8 Recovery voltage test (Classes 3, 4) . 25
6.9 Reverse voltage test (Class 2.1) . 26
6.10 Dielectric tests for panel type voltage limiting devices (Classes 3 and 4) . 27
6.10.1 Test conditions . 27
6.10.2 Power-frequency voltage withstand test . 27
6.11 Degree of protection of enclosures. 27
6.12 Environmental tests for outdoor equipment . 28

6.13 Determination of minimum current for safe short circuiting of Class 1 VLDs . 28
7 Routine tests . 29
7.1 General . 29
7.2 VLDs of Classes 3 and 4 . 29
7.3 Dielectric tests for panel type voltage limiting devices . 29
Annex A (informative) Preferred ranges of the principal properties of the VLDs. 30
Bibliography . 34

Figure 1 – Test circuit for testing of response time . 21
Figure 2 – T evaluation . 22
R
Figure 3 – Response time characteristic . 22
Figure 4 – Test circuit for testing of response time T for combined AC-DC voltage . 24
R
Figure 5 – Evaluation of response time T for combined AC-DC voltage . 24
R
Figure 6 – Circuit for the recovery voltage test . 26

Table 1 – Classes of voltage-limiting device. 10
Table 2 – Type tests . 15
Table 3 – Maximum response time as a function of DC voltages . 20
Table 4 – Response time for combined AC-DC voltages . 23
Table A.1 – Nominal triggering voltage U . 30
Tn
Table A.2 – Instantaneous triggering voltage U . 30
TI
Table A.3 – Rated current I . 30
r
Table A.4 – Short time withstand current I . 31
W
Table A.5 – Leakage current I . 31
L
Table A.6 – Making and breaking capacity . 31
Table A.7 – Lightning current impulse (8/20 µs) I . 31
imp-n
Table A.8 – High current impulse 8/20 μs and 4/10 μs I . 32
imp-high
Table A.9 – High charge impulse I . 32
imp-hc
Table A.10 – Current-time characteristic for safe short circuiting of Class 1 VLDs . 32
Table A.11 – Preferred parameters for high charge impulse I . 32
imp-hc
Table A.12 – Applicable tolerances according to IEC 61643-11:2011 . 33

– 4 – IEC 62848-2:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RAILWAY APPLICATIONS –
DC SURGE ARRESTERS AND VOLTAGE LIMITING DEVICES –

Part 2: Voltage limiting devices

FOREWORD
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