SIST-TS CLC/TS 51643-32:2020
(Main)Low-voltage surge protective devices - Part 32: Surge protective devices connected to the DC side of photovoltaic installations - Selection and application principles
Low-voltage surge protective devices - Part 32: Surge protective devices connected to the DC side of photovoltaic installations - Selection and application principles
This document describes the principles for selection, installation and coordination of SPDs intended for use in Photovoltaic (PV) systems up to 1500 V DC and for the AC side of the PV system rated up to 1000 V rms 50/60 Hz.
The photovoltaic installation extends from a PV array or a set of interconnected PV-modules to include the associated cabling and protective devices and the converter up to the connection point in the distribution board or the utility supply point.
This document considers SPDs used in different locations and in different kinds of PV systems:
- PV systems located on the top of a building;
- PV systems located on the ground like free field power plants characterized by multiple earthing and a meshed earthing system.
The term PV installation is used to refer to both kinds of PV systems. The term PV power plant is only used for extended free-field multi-earthed power systems located on the ground.
For PV installations including batteries additional requirements could be necessary.
NOTE 1 The HD 60364 series, EN 62305 series and CLC/TS 61643 12 also apply.
NOTE 2 This document deals only with SPDs and not with surge protective components integrated inside equipment (e.g. inverters, (PCE) power conversion equipment).
Überspannungsschutzgeräte für Niederspannung – Teil 32: Überspannungsschutzgeräte für den Einsatz auf der Gleichstromseite von Photovoltaik-Installationen – Auswahl und Anwendungsgrundsätze
Parafoudres basse tension - Partie 32 : Parafoudres connectés au côté courant continu des installations photovoltaïques - Principes de choix et d’application
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
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CLC/TS 51643-32:2020
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
SIST-TS CLC/TS 51643-32:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CLC/TS 51643-32:2020
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SIST-TS CLC/TS 51643-32:2020
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
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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
2
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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
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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
4
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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 51643-32:2020 includes the following significant technical changes with respect to
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 and concepts SCM and OCM,
deletion of Annex C relating to the simplified risk assessment A,
addition of a new annex dealing with telecommunication circuits.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
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Introduction
This document provides useful information for the selection of SPDs connected to photovoltaic
installations.
This document does not address the fundamentals of SPDs that are addressed in CLC/TS 61643-12
which are necessary for its correct understanding and application.
This document provides information to evaluate, with reference to the documents listed in Clause 2, the
additional needs for surge protective devices (SPDs) to be installed on the DC side and on the AC side
of a photovoltaic (PV) system, to protect against induced and direct lightning effects. It gives guidance
for selection, operation and installation of SPDs, including the selection of SPD type, surge current
values and cross sections of bonding conductors.
The specific electrical parameters of a PV array or a PV source require specific SPDs on the DC side.
This document considers SPDs used in different locations and in different kinds of PV systems. It gives
examples and provides a simplified and common approach to determine impulse discharge current
values for the DC side of different PV installations.
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1 Scope
This document describes the principles for selection, installation and coordination of SPDs intended for
use in Photovoltaic (PV) systems up to 1500 V DC and for the AC side of the PV system rated up to
1000 V RMS 50/60 Hz.
The photovoltaic installation extends from a PV array or a set of interconnected PV-modules to include
the associated cabling and protective devices and the converter up to the connection point in the
distribution board or the utility supply point.
This document considers SPDs used in different locations and in different kinds of PV systems:
— PV systems located on the top of a building;
— PV systems located on the ground like free field power plants characterized by multiple earthing
and a meshed earthing system.
The term PV installation is used to refer to both kinds of PV systems. The term PV power plant is only
used for extended free-field multi-earthed power systems located on the ground.
For PV installations including batteries additional requirements could be necessary.
NOTE 1 The HD 60364 series, EN 62305 series and CLC/TS 61643-12 also apply.
NOTE 2 This document deals only with SPDs and not with surge protective components integrated inside
equipment (e.g. inverters, (PCE) power conversion equipment).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
HD 60364-5-534:2016, Low-voltage electrical installations - Part 5-53: Selection and erection of
electrical equipment - Isolation, switching and control - Clause 534: Devices for protection against
transient overvoltages (IEC 60364-5-53:2001/A2:2015, modified)
EN 60664-1:2007, Insulation coordination for equipment within low-voltage systems - Part 1: Principles,
requirements and tests (IEC 60664-1:2007)
EN 61000-4-5, Electromagnetic compatibility (EMC) - Part 4-5: Testing and measurement techniques -
Surge immunity test (IEC 61000-4-5)
CLC/TS 61643-12, Low-voltage surge protective devices - Part 12: Surge protective devices connected
to low-voltage power distribution systems - Selection and application principles (IEC 61643-12)
EN 61643-31:2019, Low-voltage surge protective devices - Part 31: Requirements and test methods for
SPDs for photovoltaic installations (IEC 61643-31:2018)
ITU-T K.20, Resistibility of telecommunication equipment installed in a telecommunications centre to
overvoltages and overcurrents
ITU-T K.21, Resistibility of telecommunication equipment installed in customer premises to overvoltages
and overcurrents
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
PV array
assembly of electrically interconnected PV modules, PV strings or PV sub-arrays
Note 1 to entry: For the purposes of this document, a PV array is all components up to the DC input terminals
of the PCE or other power conversion equipment or DC loads. A PV array does not include its foundation, tracking
apparatus, thermal control and other such components.
Note 2 to entry: A PV array may consist of a single PV module, a single PV string, or several parallel-
connected strings, or several parallel-connected PV sub-arrays and their associated electrical components. For the
purposes of this standard, the boundary of a PV array is the output side of the PV array disconnecting device.
[SOURCE: HD 60364-7-712:2016, 712.3.3]
3.2
PV module
smallest complete environmentally protected assembly of interconnected cells
[SOURCE: HD 60364-7-712:2016, 712.3.1]
3.3
PV string
circuit of one or more series-connected modules
[SOURCE: HD 60364-7-712:2016, 712.3.2]
3.4
PV installation
erected equipment of a PV power supply installation
[SOURCE: HD 60364-7-712:2016, 712.3.14]
3.5
origin of the installation
point at which the electric energy is delivered to the electrical installation
[SOURCE: IEC 60050-826:2004, 826-10-02]
3.6
lightning protection system
LPS
complete system used to reduce physical damage due to lightning flashes to a structure
Note 1 to entry: It consists of both external and internal lightning protection systems.
[SOURCE: EN 62305-1:2011, 3.42]
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3.7
external LPS isolated from the structure to be protected
LPS with an air-termination system and down conductor system installed in such a way that the path of
the lightning current has no contact with the structure to be protected
Note 1 to entry: In an isolated LPS, dangerous sparks between the LPS and the structure are avoided
[SOURCE: EN 62305-3:2011, 3.3]
3.8
surge protective device
SPD
device that contains at least one nonlinear component that is intended to limit surge voltages and divert
surge currents
Note 1 to entry: An SPD is a complete assembly, having appropriate connecting means.
[SOURCE: EN 61643-11:2012, 3.1.1]
3.9
separation distance
s
distance between two conductive parts at which no dangerous sparking can occur
[SOURCE: EN 62305-3:2011, 3.28]
3.10
bonding bar
metal bar on which metal installations, external conductive parts, electric power and telecommunication
lines, and other cables can be bonded to an LPS
[SOURCE: EN 62305-3:2011, 3.24]
3.11
bonding conductor
conductor connecting separated conductive parts to LPS
[SOURCE: EN 62305-3:2011, 3.25]
3.12
standard test conditions
STC
standard set of reference conditions used for the testing and rating of photovoltaic cells and modules
Note 1 to entry: See product standards (e.g. EN 61215).
Note 2 to entry: The standard test conditions given in EN 61215 for PV modules are:
a) PV cell temperature of 25 °C
b) Irradiance in plane of the PV cell or module of 1000 W/m2
c) Light spectrum corresponding to an atmospheric air mass of 1,5
[SOURCE: HD 60364-7-712:2016, 712.3.13]
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3.13
open-circuit voltage under standard test conditions
U
OC STC
voltage under standard test conditions across an unloaded (open) PV module, PV string or PV array, or
on the DC side of the PV-inverter or power conversion equipment
[SOURCE: HD 60364-7-712:2016, 712.3.14, modified (addition of “-inverter or power conversion
equipment”)]
3.14
open-circuit maximum voltage
U
OC MAX
maximum voltage across an unloaded (open) PV module, PV string or PV array, or on the DC side of
the PV-inverter or power conversion equipment
Note 1 to entry: Calculation of U is performed in Annex B.
OC MAX
[SOURCE HD 60364-7-712:2016, 712.3.15 MOD]
3.15
short-circuit current under standard test conditions
I
SC STC
short-circuit current of a PV module, PV string or PV array under standard test conditions
[SOURCE: HD 60364-7-712:2016, 712.3.16]
3.16
short-circuit maximum current
I
SC MAX
maximum short-circuit current of a PV module, PV string or PV array
Note 1 to entry: Calculation of I is performed in Annex B.
SC MAX
[SOURCE: HD 60364-7-712:2016, 712.3.17]
3.17
maximum continuous operating voltage for PV application
U
CPV
maximum DC voltage which may be continuously applied to the SPD´s mode of protection
Note 1 to entry: The U values covered by this standard may exceed 1 500 V.
CPV
[SOURCE: EN 61643-31:2019, 3.1.10 modified (Notes to entry)]
3.18
short-circuit current rating of the SPD
I
SCPV
maximum prospective short-circuit current from the power system for which the SPD, in conjunction with
the disconnector specified, is rated
Note 1 to entry: This value is equal to or greater than I
SC MAX.
[SOURCE: EN 61643-31:2019, 3.1.25]
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3.19
open-circuit failure mode
OCFM
failure behaviour whereby an SPD changes to a permanent high impedance or open circuit state under
certain conditions
Note 1 to entry: A low impedance intermediate state is possible for a limited time until the final failure mode is
reached.
[SOURCE: EN 61643-31:2019, 3.1.40]
3.20
short-circuit failure mode
SCFM
failure behaviour whereby an SPD changes to a permanent low impedance or short circuit state under
certain conditions
[SOURCE: EN 61643-31:2019, 3.1.41]
3.21
rated impulse voltage
U
w
impulse withstand voltage value assigned by the manufacturer to the equipment or to a part of it,
characterizing the specified withstand capability of its insulation against transient overvoltages
Note 1 to entry: For the purpose of this standard only withstand voltages between live conductors and earth
is considered.
Note 2 to entry: U is measured with a 1,2/50 µs voltage impulse wave shape.
W
Note 3 to entry: In some other standards also called U
imp.
[SOURCE: EN 60664-1:2007, 3.9.2, modified (addition of Notes to entry)]
3.22
total discharge current
I
Total
current which flows through the earth conductor of a multipole SPD during the total discharge current
test
Note 1 to entry: The aim is to take into account cumulative effects that occur when multiple modes of protection
of a multipole SPD conduct at the same time.
Note 2 to entry: I is particularly relevant for SPDs tested according to the Type 1 SPD test, and is used
Total
for the purpose of lightning protection equipotential bonding according to EN 62305 series.
[SOURCE: EN 61643-11:2012, 3.1.44, modified (“PE or PEN conductor” replaced by “earth conductor”)]
4 Systems and equipment to be protected
Equipment within a PV installation that may require protection includes:
— The inverter, i.e. both the AC interface with the AC LV power system and the DC interface;
— The PV array;
— The wiring (installation itself);
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— Components installed between the inverter and the PV array;
— Equipment for controlling and monitoring the PV installation.
Overvoltages can destroy or degrade a PV installation or can cause malfunction, therefore PV
installations should be protected.
The evaluation of the need for protection and the proper selection of protective measures requires
information from the manufacturer concerning the withstand voltage of the equipment. If such
information is not readily available, the rated impulse voltage U for the equipment provided in 6.4.5
w
and in Table 2 can be used as a guide. Partial lightning currents can cause uncontrolled flashovers and
trigger fires. Surge protection measures may help to reduce the risk of fire (see the EN 62305 series).
5 Overvoltages in a PV installation
Several conditions may cause overvoltages in a PV installation. These include:
— direct strikes to the external lightning protection system (LPS) of the building or lightning flashes
near to the buildings and/or PV installation,
— direct strikes and lightning induced currents distributed into the electrical network,
— overvoltages created by the distribution network, e.g. those due to switching operations
Repetitive switching overvoltages (spikes) on the AC voltage created by electronic inverter / converter
technology may require special consideration for the selection of SPDs. For more information see
IEC/TR 62066.
The protection requirements in this document are based on the assumption that the cables
interconnecting the DC components of the PV installation are sufficiently protected from direct lightning
flashes, either by appropriate routing or by shielding (e.g. the use of an appropriate cable management
system).
6 Selection and erection of SPDs
6.1 General
According to CLC/TS 61643-12 and the EN 62305 series, selection and installation of SPDs for
protection of PV systems depend on many factors, but primarily:
2
— the lightning ground flash density N (flashes / km / year) or ground strike-point density N (strike-
g sg
2
point / km / year) of the location,
— the characteristics of the low-voltage power system (e.g. overhead lines or underground cables)
and of the equipment to be protected,
— whether the PV installation needs to be protected against direct lightning with an external LPS.
When installations are protected by an external LPS, the requirements for SPDs depend on:
— the selected class of the LPS (see simplified method in Annex A),
— whether the separation distance (s) is maintained between the LPS and the PV installation (isolated
LPS) or not maintained (non-isolated LPS).
For optimum inverter overvoltage protection, a direct earthing connection between the SPD and the
inverter is recommended.
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