IEC TR 61643-03:2024

IEC TR 61643-03 ®
Edition 1.0 2024-07
TECHNICAL
REPORT
Low-voltage surge protective devices –
Part 03: SPD testing guide
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IEC TR 61643-03 ®
Edition 1.0 2024-07
TECHNICAL
REPORT
Low-voltage surge protective devices –

Part 03: SPD testing guide
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-7999-1

– 2 – IEC TR 61643-03:2024 © IEC 2024
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Correspondence between this document and the tests in IEC 61643-x1 . 9
5 Probe application – residual voltage measurements . 9
5.1 Overview. 9
5.2 General . 9
5.3 Guidance for the test arrangement . 14
5.3.1 General . 14
5.3.2 Method 1: Voltage probe placed at a certain distance . 14
5.3.3 Method 2: Minimized loop of measurement lines . 16
5.3.4 Combination of method 1 and method 2 for pigtail connections . 17
6 Insulation resistance and dielectric withstand . 19
6.1 General . 19
6.2 Surfaces which are touchable after installation as for normal use are as
follows: . 19
6.3 Surfaces on which the SPD can be mounted or it can be in contact with
metal surfaces: . 20
6.4 Conclusions: . 21
6.5 Example of a test-set-up to measure the Insulation Resistance according to
9.3.7 and the Dielectric Withstand according to 9.3.8 of IEC 61643-01:— . 22
7 TOV testing . 23
7.1 TOV testing of SPDs for AC power systems . 23
7.2 TOV testing of SPDs for DC power systems . 26
8 Test application to SPDs with multiple components . 27
8.1 General . 27
8.2 Example of a multiple series spark gap with resistive/capacitive trigger
control . 28
8.3 Example of a series spark gap with resistive/capacitive trigger control and
with a parallel connected series connection of GDT + MOV(s) . 28
8.4 Example of a 3-electrode GDT with parallel MOV bypass/trigger control . 29
8.5 Example of a 4-electrode spark gap with GDT + MOV trigger control . 30
8.6 Example of a GDT with parallel connected series connection of GDT + MOV . 30
8.7 Example of a 3-electrode spark gap with trigger transformer . 31
9 SPD coordination testing . 32
9.1 Energy coordination . 32
9.2 Let-through energy (LTE) method . 32
9.2.1 General . 32
9.2.2 Method . 34
9.3 Energy and voltage protection coordination method . 35
9.3.1 General . 35
9.3.2 Coordination criteria . 35
9.3.3 Coordination techniques . 36
9.3.4 Coordination test . 36
10 System level immunity testing . 40

10.1 General . 40
10.2 SPD discharge current test under normal service conditions: . 40
10.3 Induction test due to lightning currents: . 40
10.4 Recommended test classification of system level immunity (following
IEC 61000-4-5): . 40
Annex A (informative) Critical investigation on the impulse current specification for T1
SPDs when testing Metal Oxide Varistors . 42
A.1 History and background . 42
A.2 General information . 42
A.3 Test program and instructions . 43
A.3.1 Detailed instructions . 43
A.4 Details and results of interlaboratory comparison tests . 44
A.4.1 Single disc results . 45
A.4.2 Double block results . 46
A.5 Conclusions from interlaboratory test results . 47
A.6 Further investigations and comparison tests in CTI . 47
A.6.1 Examples. 48
A.6.2 Overview single disc results. 49
A.6.3 Overview double block results . 49
A.7 Final conclusions . 49
Annex B (informative) Illustration of the terms mode of protection, current path and

current branch . 51
B.1 Examples of SPDs with one single mode of protection . 51
B.2 Examples of multimode SPDs . 52
Bibliography . 55

Figure 1 – 8/20 current impulse and induced voltage . 10
Figure 2 – Test arrangement A . 11
Figure 3 – Test arrangement B . 12
Figure 4 – Test arrangement C . 13
Figure 5 – Measured voltages of test arrangements A, B and C during 8/20 current

application . 13
Figure 6 – Routing of the measurement lines of an SPD having a single mode of
protection . 15
Figure 7 – Wrong routings of the measurement lines . 15
Figure 8 – Routing of the measurement lines of a multimode SPD, example 1 . 16
Figure 9 – Routing of the measurement lines of a multimode SPD, example 2 . 16
Figure 10 – Example for the application of method 2 at an SPD having a single mode
of protection. 17
Figure 11 – Example for the application of method 1 and method 2 where the SPD is
provided with pigtail connections . 18
Figure 12 – Wrong routings of the pigtails together with the measurement lines where
the SPD is provided with pigtail connections . 18
Figure 13 – Examples of a three-phase and single-phase test setup for use in testing
SPDs for application in TT systems under TOVs caused by faults in the high (medium)

voltage system . 24
Figure 14 – Example of a three-phase test setup for use in testing SPDs for use in IT
systems under TOVs caused by faults in the high (medium) voltage system . 25
Figure 15 – Vector diagram for the voltages in the test setup in Figure 14 . 26

– 4 – IEC TR 61643-03:2024 © IEC 2024
Figure 16 – Example of a test setup for use in testing SPDs intended to be connected
to a DC system, which is derived from an AC TT system without separation, under
TOVs caused by faults in the high (medium) voltage system . 27
Figure 17 – Example of a test setup for use in testing SPDs intended to be connected
to a DC TT system, which is derived from another earthed DC system, under TOVs
caused by faults in the high (medium) voltage system . 27
Figure 18 – multiple series spark gap with resistive /capacitive trigger control . 28
Figure 19 – series spark gap with capacitive trigger control . 29
Figure 20 – 3-electrode GDT with
...