SIST-TS CLC/TS 50539-12:2014

SLOVENSKI STANDARD
SIST-TS CLC/TS 50539-12:2014
01-februar-2014
1DGRPHãþD
SIST-TS CLC/TS 50539-12:2012
1L]NRQDSHWRVWQHQDSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL1DSUDYH]D
]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL]DVSHFLILþQHDSOLNDFLMHYNOMXþQR]
HQRVPHUQLPLGHO,]ELUDLQQDþHOD]DXSRUDER63'SULNOMXþHQLQD
IRWRQDSHWRVWQHLQãWDODFLMH
Low-voltage surge protective devices - Surge protective devices for specific application
including d.c. -- Part 12: Selection and application principles - SPDs connected to
photovoltaic installations
Überspannungsschutzgeräte für Niederspannung - Überspannungsschutzgeräte für
besondere Anwendungen einschließlich Gleichspannung -- Teil 12: Auswahl und
Anwendungsgrundsätze - Überspannungsschutzgeräte für den Einsatz in Photovoltaik
Installationen
Parafoudres basse tension - Parafoudres pour applications spécifiques incluant le
courant continu -- Partie 12: Principes de choix et d’application - Parafoudres connectés
aux installations photovoltaïques
Ta slovenski standard je istoveten z: CLC/TS 50539-12:2013
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
SIST-TS CLC/TS 50539-12:2014 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CLC/TS 50539-12:2014

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SIST-TS CLC/TS 50539-12:2014

TECHNICAL SPECIFICATION
CLC/TS 50539-12

SPÉCIFICATION TECHNIQUE
December 2013
TECHNISCHE SPEZIFIKATION

ICS 29.120.50 Supersedes CLC/TS 50539-12:2010


English version


Low-voltage surge protective devices -
Surge protective devices for specific application including d.c. -
Part 12: Selection and application principles -
SPDs connected to photovoltaic installations



Parafoudres basse tension -  Überspannungsschutzgeräte für
Parafoudres pour applications spécifiques Niederspannung -
incluant le courant continu - Überspannungsschutzgeräte für
Partie 12: Principes de choix et besondere Anwendungen einschließlich
d’application - Gleichspannung -
Parafoudres connectés aux installations Teil 12: Auswahl und
photovoltaïques Anwendungsgrundsätze -
Überspannungsschutzgeräte für den
Einsatz in Photovoltaik-Installationen




This Technical Specification was approved by CENELEC on 2013-10-21.

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, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.




CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 50539-12:2013 E

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Contents Page

Foreword . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Systems and equipment to be protected . 9
5 Overvoltages in a PV installation . 9
6 Installation and location of SPDs . 9
6.1 General . 9
6.2 PV installation without external LPS . 10
6.3 PV installation with external LPS when separation distance s is kept . 11
6.4 PV installation with external LPS when separation distance is not kept . 13
7 Equipotential bonding. 13
8 Surge protective devices (SPD) in PV installations . 15
9 Requirements for the implementation of SPDs . 15
9.1 Decision for using SPDs . 15
9.2 Selection and installation of SPDs for application in PV installation . 16
9.2.1 Selection of SPDs installed at the a.c. side of PV installations . 16
9.2.2 Selection of SPDs installed at the d.c. side of PV-installation . 18
10 Maintenance . 23
Annex A (informative) Determination of the value of I or I for SPDs for different structures
imp n
protected by a LPS according to a simplified approach . 24
A.1 Introduction . 24
A.2 PV installation on a building according to 6.4 . 24
A.2.1 General . 24
A.2.2 Case of voltage limiting and combination type SPDs (having voltage switching and
limiting components in series) . 26
A.2.3 Case of voltage switching and combination type SPDs (having voltage switching and
limiting components in parallel) . 27
A.3 Outside free field power plant PV installation according to 6.4 . 27
A.3.1 General . 27
A.3.2 Assumption . 27
A.3.3 Result . 28
Annex B (informative) Characteristic of a PV source . 30
B.1 General . 30
B.2 Calculation of U . 31
OCMAX
B.3 Calculation of I . 31
SCMAX
Annex C (normative) Simplified risk assessment based on EN 62305-2 . 32
Bibliography . 34

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Figures
Figure 1 – Current branches vs. modes of protection of an SPD. 9
Figure 2 – Installation of SPDs in case of PV installation without external LPS . 10
Figure 3 – Installation of SPDs in case of a building with external LPS when separation distance s is kept . 11
Figure 4 – Installation of SPDs in case of a building with external LPS when separation distance s is

kept – Installation with data acquisition and control system . 12
Figure 5 – Installation of SPDs in case of PV installation with external LPS when separation distance s is
not kept . 13
2
Figure 6 – Building with external LPS: Dimensions of all equipotential bonding conductors are 6 mm
except the one indicated in the figure (earthing of the SPD Type 1 located at the origin of installation) . 14
Figure 7 – Building with external LPS: Dimensions of equipotential bonding conductors in case of a non-

isolated LPS . 15
Figure 8 – Installation of SPDs on the a.c.-side and short distance between origin of installation and
PV-inverter (E < 10 m) . 17
Figure 9 – Installation of SPDs on the a.c.-side and long distance between origin of installation and
PV-inverter (E > 10 m) . 17
Figure 10 – Example of an overvoltage protection on d.c. side of a PV installation . 19
Figure 11 – I-configuration. 21
Figure 12 – U-configuration . 21
Figure 13 – L-configuration. 21
Figure 14 – ∆-configuration . 21
Figure 15 – Y-configuration . 22
Figure 16 – Single mode SPDs to be connected in Y-configuration . 22
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 . 25
Figure A.2 – Example of a structure of an extended PV installation – Free field PV power plant with
multiple earthing and a meshed earthing system . 28
Figure B.1 – Principle of a PV current source . 30
Figure B.2 – V/I characteristic of a non-linear PV current source . 30
Figure C.1 – L calculation . 33

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Tables
Table 1 – Impulse withstand voltage U for equipment between PV generator and inverter . 19
W
Table A.1 – Values of I and I for voltage limiting and combination type SPDs (having voltage
10/350 8/20
switching and limiting components in series) . 26
Table A.2 – Values of I for voltage switching and combination type SPDs (having voltage switching and
imp

limiting components in parallel) . 27
Table A.3 – Values of I and I for SPDs intended to be used in free field PV power plant with
10/350 8/20
multiple earthing and a meshed earthing system . 29
Table C.1 – Calculation of the critical length L . 32
crit

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Foreword
This document (CLC/TS 50539-12:2013) has been prepared by CLC/TC 37A "Low voltage surge protective
devices".
This document supersedes CLC/TS 50539-12:2010.
CLC/TS 50539-12:2013 includes the following significant technical changes with respect to CLC/TS 50539-
12:2010:
a) scope and definitions have been revised to align CLC/TS 50539-12 with EN 50539-11;
b) structure of the document has been revised for better clarification;
c) only Type 1 d.c. SPDs can be used for cases described in 6.4;
d) multi-earthed solar systems have been introduced for SPD selection and for current sharing calculation;
e) Table 1 (impulse withstand) has been introduced;
f) current sharing in Annex A has been revised;
g) Annex B has been created;
h) risk assessment has been introduced in Annex C.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights.

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1 Scope
This Technical Specification describes the principles for selection, location, coordination and operation of
SPDs to be connected to PV installations. The d.c. side is rated up to 1 500 V d.c. and the a.c. side, if any, is
rated up to 1 000 V rms 50 Hz.
The electrical installation starts from a PV generator or a set of interconnected PV modules with their cables,
provided by the PV generator manufacturer, up to the user installation or the utility supply point.
For PV installations including batteries, additional requirements will be necessary.
NOTE 1 HD 60364-7-712, CLC/TS 61643-12 and EN 62305-4 are also applicable.
NOTE 2 This Technical Specification deals only with SPDs, and not with SPDs components integrated inside
equipment.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
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 50539-11, Low-voltage surge protective devices – Surge protective devices for specific application
including d.c. – Part 11: Requirements and tests for SPDs in photovoltaic applications
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)
EN 61643-11, Low-voltage surge protective devices – Part 11: Surge protective devices connected to low-
voltage power systems – Requirements and tests methods (IEC 61643-1)
EN 61643-21, Low voltage surge protective devices – Part 21: Surge protective devices connected to
telecommunications and signalling networks – Performance requirements and testing methods
(IEC 61643-21)
EN 62305-2:2012, Protection against lightning – Part 2: Risk management (IEC 62305-2:2010, mod.)
EN 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within structures
(IEC 62305-4)
HD 60364-4-443, Electrical installations of buildings – Part 4-44: Protection for safety – Protection against
voltage disturbances and electromagnetic disturbances – Clause 443: Protection against overvoltages of
atmospheric origin or due to switching (IEC 60364-4-44)
HD 60364-5-534, Low-voltage electrical installations – Part 5-53: Selection and erection of electrical
equipment – Isolation, switching and control – Clause 534: Devices for protection against overvoltages
(IEC 60364-5-53)
ITU-T Recommendation K.20, Resistibility of telecommunication equipment installed in a telecommunications
centre to overvoltages and overcurrents

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ITU-T Recommendation K.21, Resistibility of telecommunication equipment installed in customer premises to
overvoltages and overcurrents
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
PV generator
assembly of PV arrays connected to one input of the inverter
3.2
PV-installation
erected equipment of a PV power supply system
3.3
open-circuit maximum voltage
U
OC MAX
maximum voltage across an unloaded (open) PV generator, PV string, PV array or on the d.c. side of the PV
inverter
Note 1 to entry: Calculation of U is performed in Annex B.
OC MAX
3.4
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]
3.5
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]
3.6
external lightning protection system
part of the LPS consisting of an air-termination system, a down-conductor system and an earth-termination
system
[SOURCE: EN 62305-1:2002, 3.43]
3.7
separation distance
s
distance between two conductive parts at which no dangerous sparking can occur
[SOURCE: EN 62305-3:2011, 3.28, modified — abbreviation 's' is added]

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3.8
lightning equipotential bonding
EB
bonding to the LPS of separated conductive parts, by direct connections or via surge protective devices, to
reduce potential differences caused by lightning current
[SOURCE: EN 62305-3:2011, 3.23]
3.9
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]
3.10
bonding conductor
conductor connecting separated conductive parts to LPS
[SOURCE: EN 62305-3:2011, 3.25]
3.11
standard test conditions
STC
test conditions specified in EN 60904-3 for PV cells and PV generators
3.12
open circuit voltage under standard test conditions
U
OC STC
voltage under standard test conditions across an unloaded (open) PV generator, PV string, PV array or on the
d.c. side of the PV inverter
3.13
short-circuit current under standard test conditions
I
SC STC
short-circuit current of a PV generator, PV string or PV array under standard test conditions
3.14
external LPS isolated from the structure to be protected
LPS with an air-termination system and down-conductor system positioned 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]

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3.15
current branch of an SPD
intended current path, between two nodes that contains one or more protective components
Note 1 to entry: A current branch of an SPD may be identical with a mode of protection of a SPD.
Note 2 to entry: This intended current path does not include additional terminals.

Figure 1 – Current branches vs. modes of protection of an SPD
[SOURCE: EN 50539-11:2013, 3.1.7]
4 Systems and equipment to be protected
Overvoltages can destroy, degrade or cause malfunction of a PV installation. Therefore, PV installations shall
be protected in presence of overvoltage risk. The most sensitive parts of the equipment should first be
protected: the inverter and the control/monitoring equipment, the PV generator and the wiring (installation
itself).
5 Overvoltages in a PV installation
Overvoltages can be found under several conditions in a PV installation. They may be
 caused by direct strike (S1) to the external lightning protection system (LPS) of the building or lightning
flashes nearby (S2) the buildings and/or PV installations,
 caused by direct strikes (S3) and lightning induced currents (S4) distributed into the electrical network,
 transmitted from the distribution network due to operations (switching).
NOTE S1, S2, S3 and S4 are abbreviations used in EN 62305 series (sources of damage).
The protection requirements within this document are based on the assumption that the cable interconnecting
the d.c. components of the PV installation is sufficiently protected from direct lightning either by appropriate
routing or by shielding, e.g. use of appropriate cable management system.
6 Installation and location of SPDs
6.1 General
According to CLC/TS 61643-12 and EN 62305 series, installation and location of SPDs for protection of PV
installations depends on multiple factors, the main ones being
 the flash ground density of the location,

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 the presence of overhead lines,
 the characteristics of the low-voltage power distribution system (e.g. overhead network or not) and of the
equipment to be protected,
 if protection measures are needed to protect the PV-installation against direct lightning impacts with an
external LPS.
When installations are protected by an external LPS, the requirements for SPD selection depends on
• the selected class of the LPS (see Annex A: simplified method),
• if the separation distance s is kept between the LPS and the PV installation (isolated LPS) or not kept
(non-isolated LPS).
For further detail on external LPS and separation distance requirements, see EN 62305-3.
NOTE The separation distance s is typically less than 1 m.
All SPDs installed on the same line have to be coordinated (see CLC/TS 61643-12).
Examples for installations of SPDs for the different cases are shown in Figure 2 to Figure 5.
6.2 PV installation without external LPS

Key
1 SPD PV type 2 according to EN 50539-11
2 SPD type 2 according to EN 61643-11
3 SPD as required in HD 60364-5-534 and according to EN 61643-11
4 SPD PV type 2 according to EN 50539-11
Figure 2 – Installation of SPDs in case of PV installation without external LPS
In general, one set of SPDs on the d.c. side and one set of SPDs on the a.c. side of the inverter should be
installed as close as possible to the inverter.
The SPD in location 2 is not needed (see 9.2.1.4) if the distance between the SPD in location 2 (main
distribution board) and the inverter is less than 10 m. In this case, only one SPD is required in location 2 (main
distribution board).

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The SPD in location 4 is not needed (see 9.2.2.4) if
 either the distance between inverter and PV generator is less than 10 m,
 or the protection level (U ) of the SPD installed in location 1 is less than or equal to 50 % of the U value
P w
of the PV generator (see 9.2.2.3).
6.3 PV installation with external LPS when separation distance s is kept
NOTE This subclause does not apply to multi earthed solar system such as outside free field power plant.

Key
1 SPD PV type 2 according to EN 50539-11
2 SPD type 2 according to EN 61643-11
3 SPD as required in HD 60364-5-534 and according to EN 61643-11
4 SPD PV type 2 according to EN 50539-11
5 air termination system
6 down conductor
7 separation distance is kept or isolated LPS
Figure 3 – Installation of SPDs in case of a building with external LPS
when separation distance s is kept
The same requirements expressed in 6.1 are to be applied except that SPD in location 3 is a SPD Type 1 and
is mandatory (see CLC/TS 61643-12, HD 60364-5-534 and EN 62305-4).
An additional example of a building with external LPS where the separation distance s is kept and an
installation that includes a data acquisition and control system is given in Figure 4. This last example shows
how the surge protection of data and control systems linked to the PV installation has to be done. The
principle applies to PV installations described in 6.2 and 6.4 as well.

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Figure 4 – Installation of SPDs in case of a building with external LPS
when separation distance s is kept – Installation with data acquisition and control system
For optimum inverter overvoltage protection, it is recommended to add a direct earthing connection between
SPD and inverter.

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6.4 PV installation with external LPS when separation distance is not kept
NOTE 1 This subclause also applies to multi-earthed solar system such as outside free field power plant when
separation distance is kept.

Key
1 SPD PV type 1 according to EN 50539-11
2 SPD type 1 according to EN 61643-11
3 SPD as required in HD 60364-5-534 and according to EN 61643-11
4 SPD PV type 1 according to EN 50539-11
5 air termination system
6 down conductor
7 equipotential bounding (separation distance is not kept = Non-isolated LPS)
Figure 5 – Installation of SPDs in case of PV installation with external LPS
when separation distance s is not kept
In that configuration, the a.c. and d.c. conductors act as parallel conductors to the equipotential bonding
conductors.
SPDs are SPD Type 1 for locations 1, 2, 3 and 4 and SPDs for locations 1 and 2 should be installed as close
as possible to the inverter. The SPD(s) for location 4 should be installed as close as possible to the PV
generator.
In very small PV installation, where the inverter and the main distribution board are connected to the same
earthing bar, SPD in location 2 is not mandatory (i.e. inverter in the main distribution board).
NOTE 2 The protection of PV generators may require specific considerations depending on cabling, routing panel
arrangement and cable length considering protection costs and possible losses.
7 Equipotential bonding
Protective conductors and other earthing conductors for functional and protective purposes cannot generally
be considered as equipotential bonding dedicated for surge and lightning protection.

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If the equipotential bonding conductors are considered as down conductors, the minimum cross section shall
2
be 50 mm copper or equivalent.
If the equipotential bonding conductors are intended to carry partial lightning currents, the minimum cross
2
section shall be 16 mm copper or equivalent.
The minimum cross section of the bonding conductor connecting internal metallic installation to the bonding
2
bar shall be 6 mm copper or equivalent.
If the equipotential bonding conductors are intended to carry only induced lightning currents the minimum
2
cross section shall be 6 mm c
...