CLC/TS 51643-32:2020

SLOVENSKI STANDARD
01-september-2020
Nadomešča:
SIST-TS CLC/TS 50539-12:2014
Nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 32. del: Naprave
za zaščito pred prenapetostnimi udari, priključene na enosmerno stran
fotonapetostnih inštalacij - Izbira in načini uporabe
Low-voltage surge protective devices - Part 32: Surge protective devices connected to
the DC side of photovoltaic installations - Selection and application principles
Ta slovenski standard je istoveten z: CLC/TS 51643-32:2020
ICS:
27.160 Sončna energija Solar energy engineering
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION CLC/TS 51643-32

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
July 2020
ICS 27.160; 29.120.50 Supersedes CLC/TS 50539-12:2013
English Version
Low-voltage surge protective devices - Part 32: Surge protective
devices connected to the DC side of photovoltaic installations -
Selection and application principles
Parafoudres basse tension - Partie 32 : Parafoudres Überspannungsschutzgeräte für Niederspannung - Teil 32:
connectés au côté courant continu des installations Überspannungsschutzgeräte für den Einsatz auf der
photovoltaïques - Principes de choix et d’application Gleichstromseite von Photovoltaik-Installationen - Auswahl
und Anwendungsgrundsätze
This Technical Specification was approved by CENELEC on 2020-05-25.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC/TS 51643-32:2020 E

Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Systems and equipment to be protected . 11
5 Overvoltages in a PV installation . 12
6 Selection and erection of SPDs. 12
6.1 General . 12
Table 1 — Selection of SPD type and cross section of bonding conductor . 13
6.2 Requirements for different PV installations . 13
6.2.1 General . 13
6.2.2 PV installation without an external LPS . 14
Figure 1 — Installation of SPDs in the case of a building without an external LPS . 14
6.2.3 PV installation with an external LPS when the separation distance (s) is
maintained (excluding multi-earthed solar systems, such as PV power plants) . 14
Figure 2 — Installation of SPDs in the case of a PV installation with an external LPS where the
separation distance (s) is maintained . 15
6.2.4 PV installation with an external LPS where the separation distance (s) cannot
be maintained (including multi-earthed systems, such as PV power plants) . 16
Figure 3 — Installation of SPDs in the case of a PV-installation with an external LPS where the
separation distance (s) cannot be maintained . 16
6.2.5 PV installation including communication and signalling circuits . 16
6.3 Selection and erection of SPDs installed on the AC side . 17
6.3.1 General . 17
6.3.2 Selection of SPDs with regard to nominal discharge current I and impulse
n
current I . 17
imp
6.3.3 Selection of SPDs with regard to voltage protection level U . 17
p
6.3.4 Installation of SPDs on the AC side . 17
Figure 4 — Installation of SPDs on the AC side with a short distance between the origin of the
installation and the PV inverter (E < 10 m) . 18
Figure 5 — Installation of SPDs on the AC side with a long distance between the origin of the
installation and the PV inverter (E ≥ 10 m) . 18
6.4 Selection and erection of SPDs installed on the DC side . 19
6.4.1 General . 19
6.4.2 Selection of SPDs with regard to nominal discharge current I and impulse
n
current I . 19
imp
6.4.3 Selection of U of SPDs on the DC side . 19
CPV
6.4.4 Selection of SPDs with regard to its leakage current I . 19
PE
6.4.5 Selection of SPDs with regard to voltage protection level U . 19
p
Table 2 — Rated impulse voltage U for equipment between PV array and inverter (where no
W
other information is available) . 20
6.4.6 Installation of SPDs on the DC side . 20
Figure 6 — Example of overvoltage protection on the DC side of a PV installation . 21
6.4.7 Cross-sections of connecting conductors for SPDs on the DC side . 21
6.4.8 Connection schemes of assemblies of SPDs on the DC side. . 22
Figure 7 — Example of connections (Y, D and U) on the DC side of a PV source. . 23
Figure 8 — Example of connections (L and I) on the DC side of a reliable earthed PV source
when distance between SPDs and the reliable earthing is less than 1 m. . 23
6.4.9 Selection of I of SPDs on the DC side . 23
SCPV
6.5 Coordination of SPDs . 24
7 Earthing Arrangement . 24
8 Requirements for the installation of surge protective devices (SPDs) in a PV system . 25
9 Maintenance . 25
Annex A (normative) Determination of the value of I or I for SPDs according to the
imp n
simplified approach for different structures protected by an LPS . 26
A.1 Introduction . 26
A.2 Building with a PV installation on the roof according to 6.2.4 . 27
Figure A.1 — Example of a structure with two external down conductors to determine the value
of the discharge current for the selection of SPDs . 29
Table A.1 — Values of I (I ) and I (I ) for voltage limiting SPDs on the DC side of
imp 10/350 n 8/20
a PV installation mounted on the roof of a building with an external LPS if the separation
distance is not maintained. . 29
Table A.2 — Values of I (I ) for voltage switching SPDs on the DC side of a PV
imp 10/350
installation mounted on the roof of a building with an external LPS, if the separation
distance is not maintained. . 30
A.3 Free- field PV power plant . 30
Figure A.2 — Example of the structure of an extended PV installation — A PV power plant with
multiple earthing and a meshed earthing system. 32
Table A.3 — Values of I (I and I (I ) for SPDs used on the DC side in PV
imp 10/350) n 8/20
power plants with a central inverter, multiple earthing and a meshed earthing system. 33
A.4 Selection of Type 1 SPDs impulse current I when A.2 or A.3 cannot be applied. . 34
imp
Annex B (informative) Characteristics of a PV source . 35
B.1 PV source characteristics . 35
Figure B.1 — Equivalent circuit diagram of a PV current source . 35
Figure B.2 — I/U characteristics of a PV source at different conditions . 36
Figure B.3 — Comparison of I/U characteristics of a PV source at different radiation conditions
and linear DC sources for SPD testing. . 37
B.2 Calculation of U . 38
OC MAX
B.3 Calculation of I . 38
SC MAX
Annex C (informative) Additional information to Clause 6: Selection and erection of SPDs and
to Clause 7: Earthing Arrangement . 39
C.1 PV installation including communication and signalling circuits . 39
Figure C.1 — Example of SPDs installed on a PV system protected by an external LPS where
the separation distance (s) is maintained – Installation includes data acquisition and
control system . 40
C.2 PV installation and dimensions of equipotential bonding conductors . 41
Figure C.2 — Example of a building with an external LPS – Dimensions of equipotential
bonding conductors when the separation distance (s) is maintained, or an isolated LPS is
used . 41
Figure C.3 — Example of a building with an external LPS – Dimensions of equipotential
bonding conductors when the separation distance (s) is not maintained. . 42
Bibliography . 43

European foreword
This document (CLC/TS 51643-32:2020) has been prepared by CLC/TC 37A ”Low-voltage surge
protective devices".
This document supersedes CLC/TS 50539-12:2013 and all of its amendments and corrigenda (if any).
CLC/TS 50539-12:2013:
 slight restructuring without impact on the content (such as changing the title of a clause by changing
the text of one clause to another),
 deletion of the current branch concept of an SPD,
 referring to EN 61634-11:2019 instead of EN 50539-11:2013,
 referring to OCFM, SCFM instead of acronyms
...