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

General Information

Status
Published
Publication Date
06-May-2020
Current Stage
PPUB - Publication issued
Completion Date
07-May-2020
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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
IEC 61643-12:2020-05(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
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

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: 3 ----------------------
– 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-

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
---------------------- Page: 4 ----------------------
IEC 61643-12:2020 © IEC 2020 – 3 –

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

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

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

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

---------------------- Page: 5 ----------------------
– 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

---------------------- Page: 6 ----------------------
IEC 61643-12:2020 © IEC 2020 – 5 –

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

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

---------------------- Page: 7 ----------------------
– 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 ....................
...

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