IEC 61643-12:2020
(Main)Low-voltage surge protective devices - Part 12: Surge protective devices connected to low-voltage power systems - Selection and application principles
Low-voltage surge protective devices - Part 12: Surge protective devices connected to low-voltage power systems - Selection and application principles
IEC 61643-12:2020 describes the principles for the selection, operation, location and coordination of SPDs to be connected to 50/60 Hz AC power circuits, and equipment rated up to 1 000 V RMS. These devices contain at least one non-linear component and are intended to limit surge voltages and divert surge currents.
NOTE 1 Additional requirements for special applications are also applicable, If required.
NOTE 2 IEC 60364 and IEC 62305-4 are also applicable.
NOTE 3 This standard deal only with SPDs and not with surge protection components (SPC) integrated inside equipment.
This third edition cancels and replaces the second edition published in 2008. This edition constitutes a technical revision.
NOTE The following differing practice of a less permanent nature exists in the USA: In the USA, SPDs tested to Class I tests are not required. This exception applies to the entire document. This edition includes the following significant technical changes with respect to the previous edition:
a) Scope: Deleted reference to 1 500 V dc
b) Added or revised some definitions
c) Added new clause 4 on Need for protection
d) Added new information on disconnecting devices
e) Revised Characteristics of SPD
f) Revised List of parameters for SPD selection
g) Added new information on Measured Limiting Voltage
e) Added or revised some Annexes
Parafoudres à basse tension - Partie 12: Parafoudres connectés aux réseaux à basse tension - Principes de choix et de mise en œuvre
IEC 61643-12:2020 décrit les principes relatifs au choix, au fonctionnement, à l'emplacement et à la coordination des parafoudres à connecter à des circuits de puissance 50 Hz/60 Hz en courant alternatif, et des matériels de puissance allant jusqu'à 1 000 V en valeur efficace. Ces dispositifs contiennent au moins un composant non linéaire et visent à limiter les tensions de choc et à écouler les courants de choc.
NOTE 1 Des exigences supplémentaires relatives à des applications particulières sont également applicables, si cela est exigé.
NOTE 2 L'IEC 60364 et l'IEC 62305-4 s'appliquent également.
NOTE 3 La présente norme traite seulement des parafoudres et non des composants de parafoudres (SPC) intégrés dans un matériel.
Cette troisième édition annule et remplace la deuxième édition parue en 2008. Cette édition constitue une révision technique.
NOTE La méthode différente suivante, à caractère moins permanent, existe aux États-Unis: Aux États-Unis, les parafoudres soumis à l'essai de Classe I ne sont pas exigés. Cette exception s'applique à l'ensemble du document.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) Domaine d'application: La référence à 1 500 V en courant continu a été supprimée
b) Certaines définitions ont été ajoutées ou révisées
c) Un nouvel Article 4 relatif à la nécessité de protection a été ajouté
d) De nouvelles informations relatives aux dispositifs de déconnexion ont été ajoutées
e) Les caractéristiques du parafoudre ont été révisées
f) La liste des paramètres pour le choix des parafoudres a été révisée
g) De nouvelles informations relatives à la tension de limitation mesurée ont été ajoutées
e) Certaines Annexes ont été ajoutées ou révisées
Nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 12. del: Naprave za zaščito pred prenapetostnimi udari za nizkonapetostne sisteme - Izbira in načela za uporabo (IEC 61643-12:2020)
Standard IEC 61643-12:2020 opisuje načela za izbiro, delovanje, lego in usklajenost naprav za zaščito pred prenapetostnimi udari, ki jih je treba priključiti na električne tokokroge z izmeničnim tokom 50/60 Hz in opremo z nazivno vrednostjo do 1000 V RMS. Te naprave vsebujejo vsaj eno nelinearno komponento ter so namenjene omejitvi sunkov napetosti in preusmeritvi toka.
OPOMBA 1: Veljajo tudi dodatne zahteve za posebne načine uporabe, če je to potrebno.
OPOMBA 2: Uporabljata se tudi standarda IEC 60364 in IEC 62305-4.
OPOMBA 3: Ta standard obravnava samo naprave za zaščito pred prenapetostnimi udari (SPD), ne pa tudi komponente za zaščito pred prenapetostnimi udari (SPC), ki so vgrajene v opremo.
Tretja izdaja razveljavlja in nadomešča drugo izdajo, objavljeno leta 2008. Ta izdaja je tehnično popravljena izdaja.
OPOMBA: V ZDA obstaja naslednja drugačna praksa, ki je manj trajna: Naprave za zaščito pred prenapetostnimi udari, ki so preskušene skladno s preskusi razreda I, v ZDA niso obvezne. Ta izjema velja za celoten dokument. Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe:
a) področje uporabe: Izbrisan sklic na 1500 V enosmernega toka;
b) dodanih ali revidiranih nekaj definicij;
c) dodana nova točka 4 o potrebi po zaščiti;
d) dodane nove informacije o ločilnih napravah;
e) revidirane lastnosti naprav za zaščito pred prenapetostnimi udari;
f) revidiran seznam parametrov za izbiro naprav za zaščito pred prenapetostnimi udari;
g) dodane nove informacije o izmerjeni mejni napetosti;
e) dodanih ali revidiranih nekaj dodatkov.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2023
Nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 12. del: Naprave
za zaščito pred prenapetostnimi udari za nizkonapetostne sisteme - Izbira in
načela za uporabo (IEC 61643-12:2020)
Low-voltage surge protective devices - Part 12: Surge protective devices connected to
low-voltage power systems - Selection and application principles (IEC 61643-12:2020)
Parafoudres à basse tension - Partie 12: Parafoudres connectés aux réseaux à basse
tension - Principes de choix et de mise en œuvre (IEC 61643-12:2020)
Ta slovenski standard je istoveten z: IEC 61643-12:2020
ICS:
29.240.10 Transformatorske postaje. Substations. Surge arresters
Prenapetostni odvodniki
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
IEC 61643-12 ®
Edition 3.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –
Part 12: Surge protective devices connected to low-voltage power systems –
Selection and application principles
Parafoudres à basse tension –
Partie 12: Parafoudres connectés aux réseaux à basse tension –
Principes de choix et de mise en œuvre
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.10 ISBN 978-2-8322-7914-4
– 2 – IEC 61643-12:2020 © IEC 2020
CONTENTS
FOREWORD . 10
INTRODUCTION . 12
0.1 General . 12
0.2 Keys to understanding the structure of this document . 12
1 Scope . 14
2 Normative references . 14
3 Terms, definitions and abbreviated terms . 15
3.1 Terms and definitions . 15
3.2 List of abbreviated terms and acronyms used in this document . 28
4 Need for protection . 29
5 Low-voltage power systems and equipment to be protected . 30
5.1 General . 30
5.2 Low-voltage power systems . 30
5.2.1 General . 30
5.2.2 Lightning overvoltages and surge currents . 30
5.2.3 Switching overvoltages . 31
5.2.4 Temporary overvoltages U . 32
TOV
5.3 Characteristics of the equipment to be protected. 33
6 Surge protective devices . 33
6.1 Basic functions of SPDs . 33
6.2 Additional requirements . 34
6.3 Classification of SPDs . 34
6.3.1 SPD: classification . 34
6.3.2 Typical design and topologies . 35
6.4 Characteristics of SPDs . 36
6.4.1 Service conditions as described in IEC 61643-11 . 36
6.4.2 List of parameters for SPD selection . 37
6.5 Additional information on characteristics of SPDs . 38
6.5.1 Information related to power-frequency voltages . 38
6.5.2 Information related to surge currents . 39
6.5.3 Information related to voltage protection level provided by SPDs . 40
6.5.4 Information related to the SPD’s status at its end of life . 42
6.5.5 I : Short-circuit current rating and I : Follow current interrupt
SCCR fi
rating . 43
6.5.6 I : Rated load current and ΔU: Voltage drop (for two-port SPDs or one-
L
port SPDs with separate input and output terminals) . 43
6.5.7 Information related to change of characteristics of SPDs . 44
7 Application of SPDs in low-voltage power systems . 44
7.1.1 General . 44
7.1.2 Consideration regarding location of the SPD depending on the classes
of test . 46
7.1.3 SPD modes of protection and installation . 46
7.1.4 Need for additional protection . 48
7.2 Selection of SPD characteristics . 55
7.2.1 General . 55
7.2.2 Selection of U , U , I , I , I , I , I and U of the SPD . 56
c T n imp max SCCR fi oc
7.2.3 Protective distance . 62
7.2.4 Expected lifetime . 62
7.2.5 Interaction between SPDs and other devices . 62
7.2.6 Choice of the voltage protection level U . 63
p
7.2.7 Coordination between the chosen SPD and other SPDs . 63
7.3 Characteristics of auxiliary devices . 66
7.3.1 Disconnecting devices . 66
7.3.2 Surge and event counters . 66
7.3.3 Status indicator . 67
Annex A (informative) Typical information required before selecting an SPD and
explanation of testing procedures . 68
A.1 Typical Information required before selecting an SPD . 68
A.1.1 System data . 68
A.1.2 SPD application considerations . 68
A.1.3 Characteristics of SPD . 69
A.1.4 Additional equipment and fittings . 69
A.2 Explanation of testing procedures used in IEC 61643-11 . 70
A.2.1 General Principles . 70
A.2.2 Test sequences and tests description . 70
Annex B (informative) Examples of relationship between U and nominal system voltage
c
and example of relationship between U and U for Metal oxide varistors (MOV) . 78
p c
B.1 Relationship between U and the nominal voltage of the system . 78
c
B.2 Relationship between U and U for Metal oxide varistors (MOV) . 78
p c
Annex C (informative) Environment – Surge voltages in LV systems . 80
C.1 General . 80
C.2 Lightning overvoltages . 80
C.2.1 General . 80
C.2.2 Surges transferred from MV to the LV system . 81
C.2.3 Overvoltages caused by direct flashes to LV distribution systems . 81
C.2.4 Induced overvoltages in LV distribution systems . 82
C.2.5 Overvoltages caused by flashes to a Lightning Protection System or to
a structure in close vicinity. 82
C.3 Switching overvoltages . 83
C.3.1 General . 83
C.3.2 General description . 84
C.3.3 Circuit-breaker and switch operations . 84
C.3.4 Fuse operations (current-limiting fuses) . 85
Annex D (informative) Partial lightning current calculations . 87
Annex E (informative) TOV in the low-voltage system due to faults between high-
voltage system and earth . 90
E.1 General . 90
E.2 References . 91
E.3 Symbols . 91
E.4 Overvoltages in LV-systems during a high-voltage earth fault . 91
E.5 Example of a TT-system – Calculation of the possible temporary
overvoltages . 93
E.5.1 Possible stresses on equipment in low-voltage installations due to earth
faults in a high-voltage system . 93
E.5.2 Characteristics of the high-voltage system . 94
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E.6 Temporary power-frequency overvoltages depending on different LV-
systems and different kinds of earthing configurations . 94
E.6.1 General . 94
E.6.2 Conclusion – Worst case SPDs stress current for SPDs HV-TOV
behaviour. . 96
E.6.3 Conclusion – Worst case test source for SPDs HV-TOV behaviour, if the
SPD is connected to ground between N-PE and / or L-PE: . 96
E.6.4 Examples of different LV-systems and their possible earthing
configurations . 97
E.7 Values of the temporary overvoltages for the US TN C system. 101
E.8 Values of temporary overvoltages used in IEC 61643-11 with explanations . 103
E.8.1 General . 103
E.8.2 Values of temporary overvoltages for US systems . 106
E.8.3 Values of temporary overvoltages for Japanese systems . 109
Annex F (informative) Coordination rules and principles . 114
F.1 General . 114
F.2 Energy coordination . 114
F.2.1 General . 114
F.2.2 Analytical studies: simple case of the coordination of two metal oxide
varistors (MOV) based SPDs . 114
F.2.3 Analytical study: case of coordination between a gap-based SPD and a
Metal oxide varistors (MOV) based SPD . 118
F.2.4 Analytical study: general coordination of two SPDs . 120
F.2.5 Let-through energy (LTE) method . 121
F.3 Coordination tests: energy and voltage protection coordination . 123
F.3.1 Introduction . 123
F.3.2 Coordination criteria . 124
F.3.3 Coordination techniques . 124
F.3.4 Test protocol . 124
Annex G (informative) Examples of application . 128
G.1 Domestic application . 128
G.2 Industrial application . 130
G.3 Presence of a lightning protection system . 134
G.4 Wind Turbines . 135
G.4.1 General . 135
G.4.2 Transient overvoltages in the DFIG converter circuit . 135
G.4.3 Transmission effect of the transient voltage due to a long cable . 136
G.4.4 Voltage coordination between SPD and equipment in wind turbine
systems . 137
G.4.5 Possible solutions for the case described in CLC/TR 50539-22 . 139
Annex H (informative) Risk assessment method and examples of application . 140
H.1 General . 140
H.2 Simplified method proposed for low voltage risk assessment as described in
IEC 60364-4-44 . 140
H.2.1 Overvoltage control . 140
H.2.2 Simplified risk assessment method . 140
H.2.3 Example 1 – Building in rural environment . 142
H.2.4 Example 2 – Building in rural environment powered by HV . 142
H.2.5 Example 3 – Building in urban environment . 143
H.2.6 Example 4 – Building in urban environment powered by HV . 143
H.2.7 Example 5 – electric vehicle supply equipment . 143
H.2.8 Example 6 – Chemical facility . 144
H.3 Factors to be considered during risk assessment . 146
H.3.1 Environmental . 146
H.3.2 Equipment and facilities . 147
H.3.3 Economics and service interruption . 148
H.3.4 Safety . 148
H.3.5 Cost of protection . 149
Annex I (informative) System stresses . 150
I.1 Lightning overvoltages and currents [5.2.2] . 150
I.1.1 Aspects of the power distribution system that affect the need for an
SPD . 150
I.1.2 Sharing of surge current within a structure . 150
I.2 Switching overvoltages [5.2.2] . 151
I.3 Temporary overvoltages U [5.2.3] . 151
TOV
Annex J (informative) Application of SPDs . 153
J.1 Location and protection given by SPDs [7.1] . 153
J.1.1 Possible modes of protection and installation [7.1.3] . 153
J.1.2 Influence of the oscillation phenomena on the protective distance [7.2.3] . 161
J.1.3 Protection zone concept [7.2.3.5] . 162
J.2 Selection of SPDs . 164
J.2.1 Selection of U [7.3.1] . 164
c
J.2.2 Coordination problems [7.3.6.2] . 165
J.2.3 Practical cases [7.2.6.3] . 167
J.3 Simple calculation of I for a class I SPD in case of a building protected
imp
by a LPS . 167
Annex K (informative) Immunity vs. rated impulse voltage withstand . 172
Annex L (informative) Examples of SPD installation in power distribution boards in
some countries . 178
Annex M (informative) Coordination when equipment has both signaling and power
terminals . 183
Annex N (informative) Short circuit backup protection and surge withstand . 190
N.1 General . 190
N.2 Information single shot 8/20 and 10/350 fuses withstand. 190
N.3 Fuse Influencing factors (reduction) for preconditioning and operating duty
test . 191
N.4 Operating duty withstand of fuses based on experimental data and
confirmed by calculations based on the parameters and limits specified by
the IEC 60269 series . 191
N.5 Behaviour of external disconnector technologies . 193
N.6 Additional requirement and test values for SPD external disconnectors used
in some countries . 193
Annex O (informative) Practical methods for testing system level immunity under
lightning discharge conditions . 197
O.1 General . 197
O.2 SPD discharge current test under normal service conditions . 197
O.3 Induction test due to lightning currents . 197
O.4 Recommended test classification of system level immunity test (following
IEC 61000-4-5) . 197
Annex P (informative) Guide for testing SPDs containing multiple components . 199
– 6 – IEC 61643-12:2020 © IEC 2020
P.1 General . 199
P.2 Example of a multiple spark gaps in series with ohmic/capacitive trigger
control . 199
P.3 Example of 2 spark gaps inserieswith capacitive trigger control and with a
parallel connected series connection of GDT + MOV(s) . 200
P.4 Example of a 3-electrode GDT with parallel MOV bypass/trigger control . 200
P.5 Example of a 4-electrode gap with GDT + MOV trigger control . 201
P.6 Example of a Spark Gap in parallel with a series-connected GDT and MOV . 202
P.7 Example of a 3-electrode gap with trigger transformer . 202
Annex Q (informative) Exceptions in the USA related to Class I tested SPDs . 204
Bibliography . 205
Figure 1 – Examples of one-port SPDs . 19
Figure 2 – Examples of two-port SPDs . 20
Figure 3 – Output voltage response of one-port and two-port SPDs to a combination
wave generator impulse . 21
Figure 4 – Examples of components and combinations of components . 36
Figure 5 – Typical curve of U versus I for Metal oxide varistors (MOV). 41
res
Figure 6 – Typical curve for a spark gap . 42
Figure 7 – Flowchart for SPD application . 45
Figure 8 – Example of connection Type 1 (CT1) . 47
Figure 9 – Example of connection Type 2 (CT2) . 47
Figure 10 – Influence of SPD connecting lead lengths . 51
Figure 11 – Possible installation scheme with intermediate earth bar when lead length
exceed 50 cm . 52
Figure 12 – Example of the need for additional SPDs when connected leads are less
than 50 cm long . 54
Figure 13 – Flow chart for the selection of an SPD. 55
Figure 14 – U and U . 57
T TOV
Figure 15 – SPD and external disconnector arrangement for continuity of supply . 60
Figure 16 – SPD and external disconnector arrangement for continuity of protection. . 60
Figure 17 – Selectivity between OCPD and disconnector in case of short-circuit . 61
Figure 18 – Typical use of two SPDs – Electrical drawing . 64
Figure A.1 – Test set-up for operating duty test . 71
Figure A.2 – Test timing diagram for first 15 impulses . 72
Figure A.3 – Test timing diagram for additional 5 impulses . 72
Figure D.1 – Simple calculation of the sum of partial lightning currents into the power
distribution system . 87
Figure E.1 – Representative schematic for possible connections to earth in substations
and LV-installations and resulting overvoltages in case of faults . 92
Figure E.2 – Example of a TT-system with combined earthing of the transformer
substation R with LV –midpoint earthing (earthed neutral) R . 93
E B
Figure E.3 – TN system (IEC 60364-4-44:2007, Figure 44B) . 97
Figure E.4 – TT system (IEC 60364-4-44:2007, Figure 44C) . 98
Figure E.5 – IT system, example a (IEC 60364-4-44:2007, Figure 44D) . 99
Figure E.6 – IT system, example b (IEC 60364-4-44:2007, Figure 44F) . 100
Figure E.7 – IT system, example c1 (IEC 60364-4-44:2007, Figure 44E) . 101
Figure E.8 – Temporary overvoltage resulting from a fault in the primary (4 wires MV-
system – direct earthing) of the distribution transformer in a TN-system according to
North American practice . 102
Figure E.9 – Typical TOV max p.u. RMS-voltages (V) Table 2, IEEE 1159-2009 . 107
Figure E.10 – Example of share the ground of the single phase center-tap grounded
100 / 200 V system and three phase (Delta) corner grounded 200 V system . 111
Figure E.11 – Typical power distribution networks of single phase center-tap grounded
100 / 200 V system in Japan . 112
Figure E.12 – Typical power system configuration in Japan . 113
Figure E.13 – TOV characteristic by faults in the high-voltage system in Japan . 113
Figure F.1 – Two Metal oxide varistors (MOV) with the same nominal discharge current . 115
Figure F.2 – Two Metal oxide varistors (MOV) with different nominal discharge currents. 117
Figure F.3 – Example of coordination of a gap-based SPD and a Metal oxide varistors
(MOV) based SPD . 120
Figure F.4 – LTE – Coordination method with standard pulse parameters . 121
Figure F.5 – SPDs arrangement for the coordination test . 126
Figure G.1 – Domestic installation . 129
Figure G.2 – Industrial installation . 132
Figure G.3 – Circuitry of industrial installation . 133
Figure G.4 – Example for a LPS . 135
Figure G.5 – Configuration of a DFIG wind turbine . 136
Figure G.6 – PWM voltage between the generator and the converter at the rotor circuit . 136
Figure G.7 – position of converter and generator . 137
Figure G.8 – A converter tested in laboratory and its L-PE voltage waveform . 138
Figure H.1 – Example of the individual sections of a power line . 142
Figure H.2 – Example of electric vehicle supply equipment . 144
Figure H.3 – Example of chemical facility . 145
Figure J.1 – Installation of surge protective devices in TN-systems . 154
Figure J.2 – Installation of surge protective devices in TT-systems (SPD downstream
of the RCD) . 156
Figure J.3 – Installation of surge protective devices in TT-systems (SPD upstream of
the RCD) . 157
Figure J.4 – Installation of surge protective devices in IT-systems without distributed
neutral . 158
Figure J.5 – Typical installation of SPD at the entrance of the installation in case of a
TN C-S system . 159
Figure J.6 – General way of installing one-port SPDs . 159
Figure J.7 – Examples of acceptable and unacceptable SPD installations regarding
EMC aspects . 160
Figure J.8 – Physical and electrical representations of a system where equipment
being protected is separated from the SPD giving protection . 161
Figure J.9 – Possible oscillation between a Metal oxide varistors (MOV) SPD and the
equipment to be protected . 161
Figure J.10 – Example of voltage doubling . 162
Figure J.11 – Subdivision of a building into protection zones . 163
Figure J.12 – Coordination of two Metal oxide varistors (MOV) . 166
– 8 – IEC 61643-12:2020 © IEC 2020
Figure L.1 – A wiring diagram of an SPD connected on the load side of the main incoming
isolator via a separate isolator (which could be included in the SPD enclosure) . 178
Figure L.2 – SPD connected to the nearest available outgoing MCB to the incoming
supply (TNS installation typically seen in the UK) . 179
Figure L.3 – A single line-wiring diagram of an SPD connected in shunt on the first
outgoing way of the distribution panel via a fuse (or MCB) . 180
Figure L.4 – SPD connected to the nearest available circuit breaker on the incoming
supply (US three phase 4W + G, TN-C-S installation) . 181
Figure L.5 – SPD connected to the nearest available circuit breaker on the incoming
supply (US single (split) phase 3W + G, 120/240 V system – typical for residential and
small office applications) . 182
Figure M.1 – Example of a PC with modem in a US power and communication system . 184
Figure M.2 – Schematic of circuit of Figure M.1 used for experimental test . 185
Figure M.3 – voltage recorded across reference points for the PC/modem during a
surge in the example (voltage and current vs. time in µs) . 186
Figure M.4 – Typical TT system used for simulations . 187
Figure M.5 – Voltage and current waveshapes measured during the application of a
surge when a multi-service SPD was installed in the circuit of the structure shown in of
Figure M.1 . 189
Figure N.1 – Schematic diagram for coordination of SPD internal and external
disconnectors with MOV . 195
Figure N.2 – Example of time-current characteristics of SPD disconnectors . 196
Figure O.1 – Example of a circuit used to perform discharge current tests under normal
service conditions . 198
Figure O.2 – Example circuit of an induction test due to lightning currents . 198
Figure P.1 – Example of multiple spark gaps in series with ohmic/capacitive trigger
control . 199
Figure P.2 – 2 spark gaps in serieswith capacitive trigger control . 200
Figure P.3 – 3-electrode GDT with parallel MOV bypass/trigger control . 201
Figure P.4 – 4-electrode spark gap with GDT + MOV trigger control . 201
Figure P.5 – Spark Gap in parallel with series-connected GDT and MOV . 202
Figure P.6 – 3-electrode spark gap with trigger transformer . 203
Table 1 – Maximum TOV values based on IEC 60364-4-44:2007 . 33
Table 2 – Preferred values of I . 40
imp
Table 3 – modes of protection for various LV systems . 48
Table 4 – Minimum recommended U of the SPD for various power systems . 56
c
Table B.1 – Relationship between U and nominal system voltage. 78
c
Table B.2 – Example of values of U /U for Metal oxide varistors (MOV) . 79
p c
Table E.1 – Permissible power-frequency stress voltages according to IEC 60364-4-44 . 92
Table E.2 – Power-frequency stress voltages and power-frequency fault voltage in low-
voltage-systems during a high-voltage earth fault . 95
Table E.3 – TOV test values for systems complying with IEC 60364 series . 103
Table E.4 – Reference test voltage values for systems complying with IEC 60364
series. 105
Table E.5 – TOV parameters for US systems . 107
Table E.6 – UL TOV values used to test SPDs in US systems . 108
Table E.7 – Nominal voltage and reference test voltage for Japanese system . 109
Table E.8 – TOV test parameters for Japanese system . 110
Table E.9 – The maximum value of TOV voltage at the difference earth fault points . 111
Table E.10 – Earth electrode class and maximum value of earth resistance . 112
Table F.1 – . 123
Table F.2 – . 123
Table F.3 – . 123
Table F.4 – Test procedure for coordination . 127
Table G.1 – Peak value of PWM voltage and du/dt at two terminals based on
investigation in 2011 in China . 137
Table G.2 – Example of characteristics of the generator alternator excitation circuit and
associated SPD . 138
Table G.3 – Comparison between the wind turbine system and low-voltage distribution
system . 139
Table H.1 – Calculation of CRL . 141
Table H.2 – Simplified method . 145
Table H.3 – IEC 62305-2 method . 146
Table J.1 – Determination of the value of I . 169
imp
Table J.2 – Determination of the value of Iimp for additional systems used in Japan . 170
Table J.3 – number of conductors related to usual structure of power supply . 171
Table J.4 – number of conductors related to additional systems used in Japan . 171
Table K.1 – Typical rated impulse voltages (derived from IEC 60664-1) . 173
Table K.2 – Selection of immunity test levels depending on the installation conditions . 176
Table K.3 – Immunity level for AC input . 176
Table M.1 – Simulation results . 187
Table N.1 – Examples of ratio between single shot withstand and full
preconditioning/operating duty test . 192
Table N.2 – Behaviour of external disconnector technologies . 193
Table N.3 – Examples of electrical ratings for SFD . 194
Table N.4 – Examples of tripping current for SSD . 194
– 10 – IEC 61643-12:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –
Part 12: Surge protective devices connected to low-voltage
power systems – Selection and application principles
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
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IEC 61643-12 ®
Edition 3.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –
Part 12: Surge protective devices connected to low-voltage power systems –
Selection and application principles
Parafoudres à basse tension –
Partie 12: Parafoudres connectés aux réseaux à basse tension –
Principes de choix et de mise en œuvre
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IEC 61643-12 ®
Edition 3.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –
Part 12: Surge protective devices connected to low-voltage power systems –
Selection and application principles
Parafoudres à basse tension –
Partie 12: Parafoudres connectés aux réseaux à basse tension –
Principes de choix et de mise en œuvre
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.10 ISBN 978-2-8322-7914-4
– 2 – IEC 61643-12:2020 © IEC 2020
CONTENTS
FOREWORD . 10
INTRODUCTION . 12
0.1 General . 12
0.2 Keys to understanding the structure of this document . 12
1 Scope . 14
2 Normative references . 14
3 Terms, definitions and abbreviated terms . 15
3.1 Terms and definitions . 15
3.2 List of abbreviated terms and acronyms used in this document . 28
4 Need for protection . 29
5 Low-voltage power systems and equipment to be protected . 30
5.1 General . 30
5.2 Low-voltage power systems . 30
5.2.1 General . 30
5.2.2 Lightning overvoltages and surge currents . 30
5.2.3 Switching overvoltages . 31
5.2.4 Temporary overvoltages U . 32
TOV
5.3 Characteristics of the equipment to be protected. 33
6 Surge protective devices . 33
6.1 Basic functions of SPDs . 33
6.2 Additional requirements . 34
6.3 Classification of SPDs . 34
6.3.1 SPD: classification . 34
6.3.2 Typical design and topologies . 35
6.4 Characteristics of SPDs . 36
6.4.1 Service conditions as described in IEC 61643-11 . 36
6.4.2 List of parameters for SPD selection . 37
6.5 Additional information on characteristics of SPDs . 38
6.5.1 Information related to power-frequency voltages . 38
6.5.2 Information related to surge currents . 39
6.5.3 Information related to voltage protection level provided by SPDs . 40
6.5.4 Information related to the SPD’s status at its end of life . 42
6.5.5 I : Short-circuit current rating and I : Follow current interrupt
SCCR fi
rating . 43
6.5.6 I : Rated load current and ΔU: Voltage drop (for two-port SPDs or one-
L
port SPDs with separate input and output terminals) . 43
6.5.7 Information related to change of characteristics of SPDs . 44
7 Application of SPDs in low-voltage power systems . 44
7.1.1 General . 44
7.1.2 Consideration regarding location of the SPD depending on the classes
of test . 46
7.1.3 SPD modes of protection and installation . 46
7.1.4 Need for additional protection . 48
7.2 Selection of SPD characteristics . 55
7.2.1 General . 55
7.2.2 Selection of U , U , I , I , I , I , I and U of the SPD . 56
c T n imp max SCCR fi oc
7.2.3 Protective distance . 62
7.2.4 Expected lifetime . 62
7.2.5 Interaction between SPDs and other devices . 62
7.2.6 Choice of the voltage protection level U . 63
p
7.2.7 Coordination between the chosen SPD and other SPDs . 63
7.3 Characteristics of auxiliary devices . 66
7.3.1 Disconnecting devices . 66
7.3.2 Surge and event counters . 66
7.3.3 Status indicator . 67
Annex A (informative) Typical information required before selecting an SPD and
explanation of testing procedures . 68
A.1 Typical Information required before selecting an SPD . 68
A.1.1 System data . 68
A.1.2 SPD application considerations . 68
A.1.3 Characteristics of SPD . 69
A.1.4 Additional equipment and fittings . 69
A.2 Explanation of testing procedures used in IEC 61643-11 . 70
A.2.1 General Principles . 70
A.2.2 Test sequences and tests description . 70
Annex B (informative) Examples of relationship between U and nominal system voltage
c
and example of relationship between U and U for Metal oxide varistors (MOV) . 78
p c
B.1 Relationship between U and the nominal voltage of the system . 78
c
B.2 Relationship between U and U for Metal oxide varistors (MOV) . 78
p c
Annex C (informative) Environment – Surge voltages in LV systems . 80
C.1 General . 80
C.2 Lightning overvoltages . 80
C.2.1 General . 80
C.2.2 Surges transferred from MV to the LV system . 81
C.2.3 Overvoltages caused by direct flashes to LV distribution systems . 81
C.2.4 Induced overvoltages in LV distribution systems . 82
C.2.5 Overvoltages caused by flashes to a Lightning Protection System or to
a structure in close vicinity. 82
C.3 Switching overvoltages . 83
C.3.1 General . 83
C.3.2 General description . 84
C.3.3 Circuit-breaker and switch operations . 84
C.3.4 Fuse operations (current-limiting fuses) . 85
Annex D (informative) Partial lightning current calculations . 87
Annex E (informative) TOV in the low-voltage system due to faults between high-
voltage system and earth . 90
E.1 General . 90
E.2 References . 91
E.3 Symbols . 91
E.4 Overvoltages in LV-systems during a high-voltage earth fault . 91
E.5 Example of a TT-system – Calculation of the possible temporary
overvoltages . 93
E.5.1 Possible stresses on equipment in low-voltage installations due to earth
faults in a high-voltage system . 93
E.5.2 Characteristics of the high-voltage system . 94
– 4 – IEC 61643-12:2020 © IEC 2020
E.6 Temporary power-frequency overvoltages depending on different LV-
systems and different kinds of earthing configurations . 94
E.6.1 General . 94
E.6.2 Conclusion – Worst case SPDs stress current for SPDs HV-TOV
behaviour. . 96
E.6.3 Conclusion – Worst case test source for SPDs HV-TOV behaviour, if the
SPD is connected to ground between N-PE and / or L-PE: . 96
E.6.4 Examples of different LV-systems and their possible earthing
configurations . 97
E.7 Values of the temporary overvoltages for the US TN C system. 101
E.8 Values of temporary overvoltages used in IEC 61643-11 with explanations . 103
E.8.1 General . 103
E.8.2 Values of temporary overvoltages for US systems . 106
E.8.3 Values of temporary overvoltages for Japanese systems . 109
Annex F (informative) Coordination rules and principles . 114
F.1 General . 114
F.2 Energy coordination . 114
F.2.1 General . 114
F.2.2 Analytical studies: simple case of the coordination of two metal oxide
varistors (MOV) based SPDs . 114
F.2.3 Analytical study: case of coordination between a gap-based SPD and a
Metal oxide varistors (MOV) based SPD . 118
F.2.4 Analytical study: general coordination of two SPDs . 120
F.2.5 Let-through energy (LTE) method . 121
F.3 Coordination tests: energy and voltage protection coordination . 123
F.3.1 Introduction . 123
F.3.2 Coordination criteria . 124
F.3.3 Coordination techniques . 124
F.3.4 Test protocol . 124
Annex G (informative) Examples of application . 128
G.1 Domestic application . 128
G.2 Industrial application . 130
G.3 Presence of a lightning protection system . 134
G.4 Wind Turbines . 135
G.4.1 General . 135
G.4.2 Transient overvoltages in the DFIG converter circuit . 135
G.4.3 Transmission effect of the transient voltage due to a long cable . 136
G.4.4 Voltage coordination between SPD and equipment in wind turbine
systems . 137
G.4.5 Possible solutions for the case described in CLC/TR 50539-22 . 139
Annex H (informative) Risk assessment method and examples of application . 140
H.1 General . 140
H.2 Simplified method proposed for low voltage risk assessment as described in
IEC 60364-4-44 . 140
H.2.1 Overvoltage control . 140
H.2.2 Simplified risk assessment method . 140
H.2.3 Example 1 – Building in rural environment . 142
H.2.4 Example 2 – Building in rural environment powered by HV . 142
H.2.5 Example 3 – Building in urban environment . 143
H.2.6 Example 4 – Building in urban environment powered by HV . 143
H.2.7 Example 5 – electric vehicle supply equipment . 143
H.2.8 Example 6 – Chemical facility . 144
H.3 Factors to be considered during risk assessment . 146
H.3.1 Environmental . 146
H.3.2 Equipment and facilities . 147
H.3.3 Economics and service interruption . 148
H.3.4 Safety . 148
H.3.5 Cost of protection . 149
Annex I (informative) System stresses . 150
I.1 Lightning overvoltages and currents [5.2.2] . 150
I.1.1 Aspects of the power distribution system that affect the need for an
SPD . 150
I.1.2 Sharing of surge current within a structure . 150
I.2 Switching overvoltages [5.2.2] . 151
I.3 Temporary overvoltages U [5.2.3] . 151
TOV
Annex J (informative) Application of SPDs . 153
J.1 Location and protection given by SPDs [7.1] . 153
J.1.1 Possible modes of protection and installation [7.1.3] . 153
J.1.2 Influence of the oscillation phenomena on the protective distance [7.2.3] . 161
J.1.3 Protection zone concept [7.2.3.5] . 162
J.2 Selection of SPDs . 164
J.2.1 Selection of U [7.3.1] . 164
c
J.2.2 Coordination problems [7.3.6.2] . 165
J.2.3 Practical cases [7.2.6.3] . 167
J.3 Simple calculation of I for a class I SPD in case of a building protected
imp
by a LPS . 167
Annex K (informative) Immunity vs. rated impulse voltage withstand . 172
Annex L (informative) Examples of SPD installation in power distribution boards in
some countries . 178
Annex M (informative) Coordination when equipment has both signaling and power
terminals . 183
Annex N (informative) Short circuit backup protection and surge withstand . 190
N.1 General . 190
N.2 Information single shot 8/20 and 10/350 fuses withstand. 190
N.3 Fuse Influencing factors (reduction) for preconditioning and operating duty
test . 191
N.4 Operating duty withstand of fuses based on experimental data and
confirmed by calculations based on the parameters and limits specified by
the IEC 60269 series . 191
N.5 Behaviour of external disconnector technologies . 193
N.6 Additional requirement and test values for SPD external disconnectors used
in some countries . 193
Annex O (informative) Practical methods for testing system level immunity under
lightning discharge conditions . 197
O.1 General . 197
O.2 SPD discharge current test under normal service conditions . 197
O.3 Induction test due to lightning currents . 197
O.4 Recommended test classification of system level immunity test (following
IEC 61000-4-5) . 197
Annex P (informative) Guide for testing SPDs containing multiple components . 199
– 6 – IEC 61643-12:2020 © IEC 2020
P.1 General . 199
P.2 Example of a multiple spark gaps in series with ohmic/capacitive trigger
control . 199
P.3 Example of 2 spark gaps inserieswith capacitive trigger control and with a
parallel connected series connection of GDT + MOV(s) . 200
P.4 Example of a 3-electrode GDT with parallel MOV bypass/trigger control . 200
P.5 Example of a 4-electrode gap with GDT + MOV trigger control . 201
P.6 Example of a Spark Gap in parallel with a series-connected GDT and MOV . 202
P.7 Example of a 3-electrode gap with trigger transformer . 202
Annex Q (informative) Exceptions in the USA related to Class I tested SPDs . 204
Bibliography . 205
Figure 1 – Examples of one-port SPDs . 19
Figure 2 – Examples of two-port SPDs . 20
Figure 3 – Output voltage response of one-port and two-port SPDs to a combination
wave generator impulse . 21
Figure 4 – Examples of components and combinations of components . 36
Figure 5 – Typical curve of U versus I for Metal oxide varistors (MOV). 41
res
Figure 6 – Typical curve for a spark gap . 42
Figure 7 – Flowchart for SPD application . 45
Figure 8 – Example of connection Type 1 (CT1) . 47
Figure 9 – Example of connection Type 2 (CT2) . 47
Figure 10 – Influence of SPD connecting lead lengths . 51
Figure 11 – Possible installation scheme with intermediate earth bar when lead length
exceed 50 cm . 52
Figure 12 – Example of the need for additional SPDs when connected leads are less
than 50 cm long . 54
Figure 13 – Flow chart for the selection of an SPD. 55
Figure 14 – U and U . 57
T TOV
Figure 15 – SPD and external disconnector arrangement for continuity of supply . 60
Figure 16 – SPD and external disconnector arrangement for continuity of protection. . 60
Figure 17 – Selectivity between OCPD and disconnector in case of short-circuit . 61
Figure 18 – Typical use of two SPDs – Electrical drawing . 64
Figure A.1 – Test set-up for operating duty test . 71
Figure A.2 – Test timing diagram for first 15 impulses . 72
Figure A.3 – Test timing diagram for additional 5 impulses . 72
Figure D.1 – Simple calculation of the sum of partial lightning currents into the power
distribution system . 87
Figure E.1 – Representative schematic for possible connections to earth in substations
and LV-installations and resulting overvoltages in case of faults . 92
Figure E.2 – Example of a TT-system with combined earthing of the transformer
substation R with LV –midpoint earthing (earthed neutral) R . 93
E B
Figure E.3 – TN system (IEC 60364-4-44:2007, Figure 44B) . 97
Figure E.4 – TT system (IEC 60364-4-44:2007, Figure 44C) . 98
Figure E.5 – IT system, example a (IEC 60364-4-44:2007, Figure 44D) . 99
Figure E.6 – IT system, example b (IEC 60364-4-44:2007, Figure 44F) . 100
Figure E.7 – IT system, example c1 (IEC 60364-4-44:2007, Figure 44E) . 101
Figure E.8 – Temporary overvoltage resulting from a fault in the primary (4 wires MV-
system – direct earthing) of the distribution transformer in a TN-system according to
North American practice . 102
Figure E.9 – Typical TOV max p.u. RMS-voltages (V) Table 2, IEEE 1159-2009 . 107
Figure E.10 – Example of share the ground of the single phase center-tap grounded
100 / 200 V system and three phase (Delta) corner grounded 200 V system . 111
Figure E.11 – Typical power distribution networks of single phase center-tap grounded
100 / 200 V system in Japan . 112
Figure E.12 – Typical power system configuration in Japan . 113
Figure E.13 – TOV characteristic by faults in the high-voltage system in Japan . 113
Figure F.1 – Two Metal oxide varistors (MOV) with the same nominal discharge current . 115
Figure F.2 – Two Metal oxide varistors (MOV) with different nominal discharge currents. 117
Figure F.3 – Example of coordination of a gap-based SPD and a Metal oxide varistors
(MOV) based SPD . 120
Figure F.4 – LTE – Coordination method with standard pulse parameters . 121
Figure F.5 – SPDs arrangement for the coordination test . 126
Figure G.1 – Domestic installation . 129
Figure G.2 – Industrial installation . 132
Figure G.3 – Circuitry of industrial installation . 133
Figure G.4 – Example for a LPS . 135
Figure G.5 – Configuration of a DFIG wind turbine . 136
Figure G.6 – PWM voltage between the generator and the converter at the rotor circuit . 136
Figure G.7 – position of converter and generator . 137
Figure G.8 – A converter tested in laboratory and its L-PE voltage waveform . 138
Figure H.1 – Example of the individual sections of a power line . 142
Figure H.2 – Example of electric vehicle supply equipment . 144
Figure H.3 – Example of chemical facility . 145
Figure J.1 – Installation of surge protective devices in TN-systems . 154
Figure J.2 – Installation of surge protective devices in TT-systems (SPD downstream
of the RCD) . 156
Figure J.3 – Installation of surge protective devices in TT-systems (SPD upstream of
the RCD) . 157
Figure J.4 – Installation of surge protective devices in IT-systems without distributed
neutral . 158
Figure J.5 – Typical installation of SPD at the entrance of the installation in case of a
TN C-S system . 159
Figure J.6 – General way of installing one-port SPDs . 159
Figure J.7 – Examples of acceptable and unacceptable SPD installations regarding
EMC aspects . 160
Figure J.8 – Physical and electrical representations of a system where equipment
being protected is separated from the SPD giving protection . 161
Figure J.9 – Possible oscillation between a Metal oxide varistors (MOV) SPD and the
equipment to be protected . 161
Figure J.10 – Example of voltage doubling . 162
Figure J.11 – Subdivision of a building into protection zones . 163
Figure J.12 – Coordination of two Metal oxide varistors (MOV) . 166
– 8 – IEC 61643-12:2020 © IEC 2020
Figure L.1 – A wiring diagram of an SPD connected on the load side of the main incoming
isolator via a separate isolator (which could be included in the SPD enclosure) . 178
Figure L.2 – SPD connected to the nearest available outgoing MCB to the incoming
supply (TNS installation typically seen in the UK) . 179
Figure L.3 – A single line-wiring diagram of an SPD connected in shunt on the first
outgoing way of the distribution panel via a fuse (or MCB) . 180
Figure L.4 – SPD connected to the nearest available circuit breaker on the incoming
supply (US three phase 4W + G, TN-C-S installation) . 181
Figure L.5 – SPD connected to the nearest available circuit breaker on the incoming
supply (US single (split) phase 3W + G, 120/240 V system – typical for residential and
small office applications) . 182
Figure M.1 – Example of a PC with modem in a US power and communication system . 184
Figure M.2 – Schematic of circuit of Figure M.1 used for experimental test . 185
Figure M.3 – voltage recorded across reference points for the PC/modem during a
surge in the example (voltage and current vs. time in µs) . 186
Figure M.4 – Typical TT system used for simulations . 187
Figure M.5 – Voltage and current waveshapes measured during the application of a
surge when a multi-service SPD was installed in the circuit of the structure shown in of
Figure M.1 . 189
Figure N.1 – Schematic diagram for coordination of SPD internal and external
disconnectors with MOV . 195
Figure N.2 – Example of time-current characteristics of SPD disconnectors . 196
Figure O.1 – Example of a circuit used to perform discharge current tests under normal
service conditions . 198
Figure O.2 – Example circuit of an induction test due to lightning currents . 198
Figure P.1 – Example of multiple spark gaps in series with ohmic/capacitive trigger
control . 199
Figure P.2 – 2 spark gaps in serieswith capacitive trigger control . 200
Figure P.3 – 3-electrode GDT with parallel MOV bypass/trigger control . 201
Figure P.4 – 4-electrode spark gap with GDT + MOV trigger control . 201
Figure P.5 – Spark Gap in parallel with series-connected GDT and MOV . 202
Figure P.6 – 3-electrode spark gap with trigger transformer . 203
Table 1 – Maximum TOV values based on IEC 60364-4-44:2007 . 33
Table 2 – Preferred values of I . 40
imp
Table 3 – modes of protection for various LV systems . 48
Table 4 – Minimum recommended U of the SPD for various power systems . 56
c
Table B.1 – Relationship between U and nominal system voltage. 78
c
Table B.2 – Example of values of U /U for Metal oxide varistors (MOV) . 79
p c
Table E.1 – Permissible power-frequency stress voltages according to IEC 60364-4-44 . 92
Table E.2 – Power-frequency stress voltages and power-frequency fault voltage in low-
voltage-systems during a high-voltage earth fault . 95
Table E.3 – TOV test values for systems complying with IEC 60364 series . 103
Table E.4 – Reference test voltage values for systems complying with IEC 60364
series. 105
Table E.5 – TOV parameters for US systems . 107
Table E.6 – UL TOV values used to test SPDs in US systems . 108
Table E.7 – Nominal voltage and reference test voltage for Japanese system . 109
Table E.8 – TOV test parameters for Japanese system . 110
Table E.9 – The maximum value of TOV voltage at the difference earth fault points . 111
Table E.10 – Earth electrode class and maximum value of earth resistance . 112
Table F.1 – . 123
Table F.2 – . 123
Table F.3 – . 123
Table F.4 – Test procedure for coordination . 127
Table G.1 – Peak value of PWM voltage and du/dt at two terminals based on
investigation in 2011 in China . 137
Table G.2 – Example of characteristics of the generator alternator excitation circuit and
associated SPD . 138
Table G.3 – Comparison between the wind turbine system and low-voltage distribution
system . 139
Table H.1 – Calculation of CRL . 141
Table H.2 – Si
...
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