IEC 61643-32:2017

IEC 61643-32 ®
Edition 1.0 2017-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –
Part 32: Surge protective devices connected to the d.c. side of photovoltaic
installations – Selection and application principles

Parafoudres basse tension –
Partie 32: Parafoudres connectés au côté courant continu des installations
photovoltaïques – Principes de choix et d'application

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IEC 61643-32 ®
Edition 1.0 2017-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –

Part 32: Surge protective devices connected to the d.c. side of photovoltaic

installations – Selection and application principles

Parafoudres basse tension –
Partie 32: Parafoudres connectés au côté courant continu des installations

photovoltaïques – Principes de choix et d'application

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-4583-5

– 2 – IEC 61643-32:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Systems and equipment to be protected . 12
5 Overvoltages in a PV installation . 12
6 Installation and location of SPDs . 13
6.1 General . 13
6.2 Requirements for different PV installations:. 15
6.2.1 PV installation without an external LPS . 15
6.2.2 PV installation with an external LPS when the separation distance (s) is
maintained (excluding multi-earthed solar systems, such as PV power
plants) . 16
6.2.3 PV installation with an external LPS where the separation distance (s)
cannot be maintained (including multi-earthed systems, such as PV
power plants) . 17
6.2.4 PV installation including communication and signalling circuits . 18
7 Equipotential bonding . 18
8 Requirements for the installation of surge protective devices (SPDs) in a
PV system . 19
9 Selection and installation of SPDs in PV installations . 19
9.1 Selection of SPDs on the AC side . 19
9.1.1 General . 19
9.1.2 Selection of SPDs with regard to nominal discharge current I and
n
impulse current I . 19
imp
9.1.3 Selection of SPDs with regard to voltage protection level U . 20
P
9.1.4 Installation of SPDs on the AC side . 20
9.2 Selection of SPDs installed on the DC side . 22
9.2.1 General . 22
9.2.2 Selection of SPDs with regard to nominal discharge current I and
n
impulse current I . 22
imp
9.2.3 Selection of U of SPDs on the DC side . 22
CPV
9.2.4 Selection of SPDs with regard to voltage protection level U . 22
p
9.2.5 Installation of SPDs on the DC side . 23
9.2.6 Cross-sections of connecting conductors for SPDs on the DC side . 24
9.2.7 Internal connection schemes of multipole SPDs or combinations of
SPDs with a single mode of protection on the DC side . 25
9.2.8 Selection of I of SPDs on the DC side . 26
SCPV
9.2.9 Coordination of SPDs . 27
10 Maintenance . 27
Annex A (normative) Determination of the value of I or I for SPDs according to
imp n
the simplified approach for different structures protected by an LPS . 28
A.1 General . 28
A.2 Building with a PV installation on the roof according to 6.2.3 . 29
A.3 Free- field PV power plant. 32
Annex B (informative) Characteristics of a PV source . 35

B.1 PV source characteristics. 35
B.2 Calculation of U . 36
OC MAX
B.3 Calculation of I . 37
SC MAX
Annex C (informative) Additional information to clause 6: Installation and location of
SPD and to clause 7: Equipotential bonding . 38
C.1 PV installation including communication and signalling circuits . 38
C.2 PV installation and dimensions of equipotential bonding conductors . 40
Annex D (informative) Exceptions in the USA related to Class I tested SPDs . 42
Bibliography . 43

Figure 1 – Installation of SPDs in the case of a building without an external LPS . 15
Figure 2 – Installation of SPDs in the case of a PV installation with an external LPS
where the separation distance (s) is maintained . 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 . 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) . 21
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) . 21
Figure 6 – Example of overvoltage protection on the DC side of a PV installation . 24
Figure 7 – Example of SPD connections on the DC side of an unearthed PV source . 25
Figure 8 – Example of SPD connection on the DC side of a reliable earthed PV source . 26
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 . 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 . 33
Figure B.1 – Schematic of a PV current source . 35
Figure B.2 – U/I characteristics of a non-linear PV current source . 35
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 . 39
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 . 40
Figure C.3 – Example of a building with an external LPS – Dimensions of equipotential
bonding conductors when the separation distance (s) is not maintained . 41

Table 1 – Selection of SPD test class and cross section of bonding conductor . 14
Table 2 – Rated impulse voltage U for equipment between PV array and inverter
w
(where no other information is available) . 23
Table A.1 – Values of I (I ) and I (I ) for voltage-limiting SPDs on the DC
imp 10/350 n 8/20
side of a PV installation mounted on the roof of a building with an external LPS if the
separation distance is not maintained . 31
Table A.2 – Values of I (I ) for voltage-switching SPDs on the DC side of a
imp 10/350
PV installation mounted on the roof of a building with an external LPS, if the
separation distance is not maintained . 31
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

– 4 – IEC 61643-32:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 32: Surge protective devices connected to the d.c. side of
photovoltaic installations – 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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61643-32 has been prepared by subcommittee 37A: Low-voltage
surge protective devices, of IEC technical committee 37: Surge arresters.
The text of this International Standard is based on the following documents:
FDIS Report on voting
37A/302/FDIS 37A/303/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

The following differing practices of a less permanent nature exist in the countries indicated
below.
Annex D: Class I tested SPDs are not required (United States)
A list of all parts of the IEC 61643 series can be found, under the general title Low-voltage
surge protection devices, on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
 reconfirmed,
 withdrawn,
 replaced by a revised edition, or
 amended.
The contents of the corrigendum of June 2019 have been included in this copy.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 61643-32:2017 © IEC 2017
INTRODUCTION
This part of IEC 61643 provides useful information for the selection of SPDs connected to
photovoltaic installations.
This part of IEC 61643 provides information to evaluate, with reference to the IEC 62305
series, IEC 60364 series and IEC 61643-12, the additional needs for surge protective devices
(SPDs) to be installed on the DC 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 test class, surge current values and cross section of
bonding conductors. Guidance for selection of SPDs connected to the AC side is also given.
The specific electrical parameters of a PV array or a PV source require specific SPDs on the
DC side.
This part of IEC 61643 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.

LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 32: Surge protective devices connected to the DC side of
photovoltaic installations – Selection and application principles

1 Scope
This part of IEC 61643 describes the principles for selection, installation and coordination of
SPDs intended for use in Photovoltaic (PV) systems up to 1 500 V DC and for the AC side of
the PV system rated up to 1 000 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 inverter up to the connection
point in the distribution board or the utility supply point.
This part of IEC 61643 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 may be necessary.
NOTE 1 IEC 60364 series, IEC 62305 series and IEC 61643-12 also apply.
NOTE 2 This standard 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.
IEC 60364-4-44:2007, Low-voltage electrical installations – Part 4-44: Protection for safety –
Protection against voltage disturbances and electromagnetic disturbances
IEC 60364-4-44:2007/AMD1:2015
IEC 60364-5-53:2015, Electrical installations of buildings – Part 5-53: Selection and erection
of electrical equipment – Isolation, switching and control
IEC 60364-5-54, Low-voltage electrical installations – Part 5-54: Selection and erection of
electrical equipment – Earthing arrangements and protective conductors
IEC 60364-7-712:2017, Low voltage electrical installations – Part 7-712: Requirements for
special installations or locations – Solar photovoltaic (PV) power supply systems
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests

– 8 – IEC 61643-32:2017 © IEC 2017
IEC 61000-4-5:2014, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
IEC 61643-11:2011, Low-voltage surge protective devices – Part 11: Surge protective devices
connected to low-voltage power systems – Requirements and test methods
IEC 61643-12, Low-voltage surge protective devices – Part 12: Surge protective devices
connected to low-voltage power distribution systems – Selection and application principles
IEC 61643-21, Low voltage surge protective devices – Part 21: Surge protective devices
connected to telecommunications and signalling networks – Performance requirements and
testing methods
IEC 61643-22, Low-voltage surge protective devices – Part 22: Surge protective devices
connected to telecommunications and signalling networks – Selection and application
principles
IEC 61643-31, Low-voltage surge protective devices – Part 31: Surge protective devices
connected to the DC side of photovoltaic installations – Requirements and test methods
IEC 62305-2, Protection against lightning – Part 2: Risk management
IEC 62305-3:2010, Protection against lightning – Part 3: Physical damage to structures and
life hazard
IEC 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within
structures
ITU-T, Recommendation K.20, Resistibility of telecommunication equipment installed in a
telecommunications centre to overvoltages and overcurrents
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.
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 http://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 d.c. 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.
___________
Under preparation: Stage at the time of publication: IEC/FDIS 61643-31:2017.

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: IEC 60364-7-712:2017, 712.3.4]
3.2
PV module
smallest complete environmentally protected assembly of interconnected cells
[SOURCE: IEC 60364-7-712:2017, 712.3.2]
3.3
PV string
circuit of one or more series-connected modules
[SOURCE: IEC 60364-7-712:2017, 712.3.3]
3.4
PV installation
erected equipment of a PV power supply installation
[SOURCE: IEC 60364-7-712:2017, 712.3.11]
3.5
origin of the electrical 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: IEC 62305-1:2010, 3.42]
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: IEC 62305-3:2010, 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: IEC 61643-11:2011, 3.1.1]

– 10 – IEC 61643-32:2017 © IEC 2017
3.9
separation distance
s
distance between two conductive parts at which no dangerous sparking can occur
[SOURCE: IEC 62305-3:2010, 3.28]
3.10
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: IEC 62305-3:2010, 3.23]
3.11
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: IEC 62305-3:2010, 3.24]
3.12
bonding conductor
conductor connecting separated conductive parts to LPS
[SOURCE: IEC 62305-3:2010, 3.25]
3.13
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 standard (eg. IEC 61215).
Note 2 to entry: The standard test conditions given in IEC 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: IEC 60364-7-712:2017, 712.3.12]
3.14
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: IEC 60364-7-712:2017, 712.3.13, modified (addition of "-inverter or power
conversion equipment")]
3.15
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
3.16
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: IEC 60364-7-712:2017, 712.3.15]
3.17
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.
SCMAX
[SOURCE: IEC 60364-7-712:2017, 712.3.16]
3.18
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: This value is equal to, or greater than U .
OC MAX
[SOURCE: IEC 61643-31:−, 3.1.10]
3.19
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: IEC 61643-31:−, 3.1.25]
3.20
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: IEC 61643-31:−, 3.1.40]
3.21
Short-Circuit Failure Mode
SCFM
failure behaviour whereby an SPD changes to a permanent low impedance or short circuit
state under certain conditions
[SOURCE: IEC 61643-31:−, 3.1.41]

– 12 – IEC 61643-32:2017 © IEC 2017
3.22
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: IEC 60664-1:2007, 3.9.2, modified (addition of Notes to entry)]
3.23
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 test class I, and is used for the purpose
Total
of lightning protection equipotential bonding according to IEC 62305 series.
[SOURCE: IEC 61643-11:2011, 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)
– 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
w
equipment provided in Subclause 9.1.2 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 IEC 62305 series).
5 Overvoltages in a PV installation
Several conditions may cause overvoltages in a PV installation. These include:
– direct strikes (S1) to the external lightning protection system (LPS) of the building or
lightning flashes near (S2) to the buildings and/or PV installation,
– direct strikes (S3) and lightning induced currents (S4) distributed into the electrical
network,
– overvoltages created by the distribution network, e.g., those due to switching operations
NOTE 1 S1, S2, S3 and S4 are addressed in IEC 62305 series.
NOTE 2 Overvoltages are described in IEC 60364-4-44.
Repetitive switching overvoltages (spikes) on the AC voltage created by electronic inverter /
converter technology may require special consideration for the selection of SPDs.
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 Installation and location of SPDs
6.1 General
According to IEC 61643-12 and the IEC 62305 series, selection and installation of SPDs for
protection of PV systems depend on many factors, but primarily:
– the lightning ground flash density N (1/km / year) or the isokeraunic level T (number of
G D
thunder storm days per 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 further details on external LPS and separation distance requirements, see IEC 62305-3.
For optimum inverter overvoltage protection, a direct earthing connection between the SPD
and the inverter is recommended.
The selection of SPD test class and minimum cross section of bonding conductors shall be
done according to Table 1.
– 14 – IEC 61643-32:2017 © IEC 2017
Table 1 – Selection of SPD test class and
cross section of bonding conductor
SPD test class and corresponding bonding cross sectional areas
Situation SPD at Location SPD at Location SPD at Location
and
3 2 1 4
SPD tested according SPD tested according SPD tested according
to class I acc. to to class II acc. to to class II acc. to
a a a
IEC 61643-11 IEC 61643-11 IEC 61643-31
2 2 2
16 mm 6 mm 6 mm
Installation of SPDs in case of PV
or
installation without external LPS
(see 6.2.1)
SPD tested according
to class II acc. to
a
IEC 61643-11
6 mm
Installation of SPDs in case of a SPD tested according SPD tested according SPD tested according
building with external LPS when to class I acc. to to class II acc. to to class II acc. to
separation distance s is kept IEC 61643-11 IEC 61643-11 IEC 61643-31
2 2 2
16 mm 6 mm 6 mm
(see 6.2.2)
Installation of SPDs in case of a SPD tested according SPD tested according SPD tested according
building with external LPS when to class I acc. to to class I acc. to to class I acc. to
a
separation distance s is not kept IEC 61643-11 IEC 61643-11 IEC 61643-31
2 2 2
16 mm 16 mm 16 mm
(see 6.2.3 and Annex A)
a
If necessary
NOTE The minimum cross sectional requirements of conductors differ in some countries. The foreword in
IEC 62305-3 explains these differences.

SPDs according to IEC 61643-31 are marked with a PV sign.

6.2 Requirements for different PV installations:
6.2.1 PV installation without an external LPS
Main distribution board PV inverter PV array
Grid
SPD
SPD SPD
SPD
Main
earthing
bar
Earth termination system of building
IEC
Legend
1 Class II tested SPD according to IEC 61643-31
2 Class II tested SPD according to IEC 61643-11
3 Class I or class II tested SPD according to IEC 61643-11
4 Class II tested SPD according to IEC 61643-31
Figure 1 – Installation of SPDs in the case of a
building without an external LPS
In general, two SPDs on the DC side (location 1 and 4) and two SPDs on the AC side of the
inverter (location 3 and 2) should be installed as shown in Figure 1.
NOTE When a shielded DC power cable is used, the equipment interfaces with such cable are inherently
protected from induced overvoltages.
The SPD in location 2 is not required if:
• The distance between the SPD in the main distribution board and the inverter is less than
10 m, and the PE conductor is routed with the AC power conductors (see 9.1.3). In this
case a single SPD shall be installed in the main distribution board at location 3.
or
• The inverter and the main distribution board are connected to the same earthing bar with a
cable length each less than or equal to 0.5 m (e.g., the inverter is located inside the main
distribution board).
The SPD in location 4 is not required if:
• The distance between the inverter and the PV array is less than 10 m and the protection
) of the SPD installed in location 1 is less than or equal to 0,8 U of the PV
level (U
p w
array’s withstand voltage (see 9.2.3),
or
– 16 – IEC 61643-32:2017 © IEC 2017
) of the SPD installed in location 1 is less than or equal to 0,5 U
• The protection level (U
p w
of the PV array’s withstand voltage and the PE conductor is routed close to the DC
conductors.
6.2.2 PV installation with an external LPS when the separation distance (s) is
maintained (excluding multi-earthed solar systems, such as PV power plants)
This is a preferable solution compared to the case where the separation distance s is not
maintained.
Measures to reduce the separation distance (s) (e.g. multiple or meshed down conductors) or
use of an external LPS isolated from the structure (the PV system being part of that structure)
to be protected, are preferred in comparison to the measures required in 6.2.3.
An external LPS isolated from the structure to be protected may be used only in the vicinity of
the PV-system (partly isolated LPS).
LPS
Main distribution board PV inverter PV array
Grid 1 4
s
SPD
SPD
SPD SPD
Earth termination system of building
Main
earthing
bar
IEC
Legend
1 Class II tested SPD according to IEC 61643-31
2 Class II tested SPD according to IEC 61643-11
3 Class I tested SPD according to IEC 61643-11
4 Class II tested SPD according to IEC 61643-31
5 LPS air termination system
6 LPS down conductor
Figure 2 – Installation of SPDs in the case of a PV installation
with an external LPS where the separation distance (s) is maintained
In general, two SPDs on the DC side (location 1 and 4) and two SPDs on the AC side of the
inverter (location 3 and 2) should be installed, as shown in Figure 2.
The SPD in location 2 is not required if:
• The distance between the SPDs in the main distribution board and the inverter is less than
10 m and the induced voltage to lightning current flowing in the down conductor can be
ignored (see IEC 62305-4).
or
• The inverter and the main distribution board are connected to the same earthing bar with a
cable of length less than or equal to 0.5 m (e.g. the inverter is located inside the main
distribution board).
The SPD in location 4 is not required if:
• The distance between the inverter and the PV array is less than 10 m and the protection
level (U ) of the SPD installed in location 1 is less than or equal to 0,8 U of the PV
p w
array’s withstand voltage (see 9.2.3),
or
• The protection level (U ) of the SPD installed in location 1 is less than or equal to 0,5 U
p w
of the PV array’s withstand voltage and the PE conductor is routed close to the DC
conductors.
6.2.3 PV installation with an external LPS where the separation distance (s) cannot
be maintained (including multi-earthed systems, such as PV power plants)
LPS
Main distribution board PV inverter PV array
Grid 1 4
E
SPD
SPD
SPD
3 SPD
Earth termination system of build
...