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MS 1837:2010
INSTALLATION OF GRID-CONNECTED PHOTOVOLTAIC (PV) SYSTEM (FIRST
REVISION) ICS: 27.160 Descriptors: solar energy engineering,
grid-connected PV system
© Copyright 2010
DEPARTMENT OF STANDARDS MALAYSIA
MALAYSIAN STANDARD
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DEVELOPMENT OF MALAYSIAN STANDARDS
The Department of Standards Malaysia (STANDARDS MALAYSIA) is the
national standards and accreditation body of Malaysia.
The main function of STANDARDS MALAYSIA is to foster and promote
standards,
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international trade and
furthering international cooperation in relation to standards
and standardisation.
Malaysian Standards (MS) are developed through consensus by
committees which
comprise balanced representation of producers, users, consumers
and others with
relevant interests, as may be appropriate to the subject at
hand. To the greatest
extent possible, Malaysian Standards are aligned to or are
adoption of international
standards. Approval of a standard as a Malaysian Standard is
governed by the
Standards of Malaysia Act 1996 [Act 549]. Malaysian Standards
are reviewed
periodically. The use of Malaysian Standards is voluntary except
in so far as they are
made mandatory by regulatory authorities by means of
regulations, local by-laws or
any other similar ways.
STANDARDS MALAYSIA has appointed SIRIM Berhad as the agent to
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For further information on Malaysian Standards, please
contact:
Department of Standards Malaysia OR SIRIM Berhad Ministry of
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0002 Tel: 60 3 5544 6000 Fax: 60 3 8319 3131 Fax: 60 3 5510 8095
http://www.standardsmalaysia.gov.my http://www.sirim.my E-mail:
[email protected] E-mail: [email protected]
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MS 1837:2010
© STANDARDS MALAYSIA 2010 - All rights reserved i
CONTENTS
Page
Committee representation
.........................................................................................................
iii
Foreword
................................................................................................................................iv
1 Scope
...............................................................................................................................
1
2 Normative
references.......................................................................................................
1
3 Terms and
definitions.......................................................................................................
2
4 General requirements
......................................................................................................
7
5 Protection
requirements...................................................................................................
7
6 Wiring
requirements.......................................................................................................
15
7 Component requirements
..............................................................................................
17
8
Earthing..........................................................................................................................
20
9 Marking requirements
....................................................................................................
20
10 Documentation
...............................................................................................................
22
11
Commissioning...............................................................................................................
22
Table 1 Current rating of PV array circuits
........................................................................
17
Figure 1 Schematic diagram of a grid-connected PV system (single
phase)……………..…9 Figure 2 Schematic diagram of a grid-connected PV
system (three phase)…….........…...10 Figure 3 PV string wiring
with minimum loop area
.............................................................
15
Figure B1 Example of sign required on PV array connection box
(9.2) ............................... 26
Figure B2 Example of sign required adjacent to PV array main
switch (9.3.2) .................... 26
Figure B3 Example of sign required adjacent to inverter main
switch (9.3.3) ...................... 26
Figure B4 Example of fire emergency information sign required on
the main
switchboard (9.4.1)
...............................................................................................
27
Figure B5 Example of shutdown procedure (9.5)
.................................................................
28
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MS 1837:2010
ii © STANDARDS MALAYSIA 2010 - All rights reserved
CONTENTS (continued)
Page Annex A Characteristics of PV
arrays.................................................................................
24
Annex B Examples of signs
................................................................................................
26
Annex C Maintenance
requirements...................................................................................
29 Annex D Changes between MS1837:2005 and MS 1837:2010 (First
revision) ................. 31
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MS 1837:2010
© STANDARDS MALAYSIA 2010 - All rights reserved iii
Committee representation The Industry Standards Committee on
Generation, Transmission and Distribution of Energy (ISC E) under
whose authority this Malaysian Standard was developed, comprises
representatives from the following organisations: Association of
Consulting Engineers Malaysia Department of Standards Malaysia
Federation of Malaysian Manufacturers Jabatan Kerja Raya Malaysia
Malaysian Association of Standards Users Malaysian Cable
Manufacturers Association Malaysian Electrical Appliances and
Distribution Association Malaysian Green Technology Corporation
Ministry of Domestic Trade, Co-operatives and Consumerism Ministry
of International Trade and Industry Persatuan Kontraktor Elektrikal
dan Mekanikal Melayu Malaysia Persatuan Penjana Kuasa Bebas SIRIM
Berhad (Secretariat) SIRIM QAS International Sdn Bhd Suruhanjaya
Komunikasi dan Multimedia Malaysia Suruhanjaya Tenaga Tenaga
Nasional Berhad The Electrical and Electronics Association of
Malaysia The Institution of Engineers, Malaysia Universiti
Teknologi Malaysia The Technical Committee on Renewable Energies
which supervised the development of this Malaysian Standard
consists of representatives from the following organisations:
Association of Consulting Engineers Malaysia Bank Pembangunan
Malaysia Berhad Core Competencies Sdn Bhd Department of Environment
Felda Palm Industries Sdn Bhd Forest Research Institute Malaysia
Malaysian Photovoltaic Industry Association Ministry of Energy,
Green Technology and Water National Solid Waste Management
Department Sarawak Energy Berhad SIRIM Berhad (Renewable Energy
Research Centre) SIRIM Berhad (Secretariat) Suruhanjaya Tenaga
Tenaga Nasional Berhad (Distribution Division) The Institution of
Engineers, Malaysia TNB Research Sdn Bhd Universiti Tenaga Nasional
The Working Group on Solar Photovoltaic Systems which developed
this Malaysian Standard consists of representatives from the
following organisations: Jabatan Kerja Raya Malaysia Malaysian
Photovoltaic Industry Association Ministry of Energy, Green
Technology and Water Optimal Power Solutions Sdn Bhd Sabah
Electricity Sdn Bhd Sarawak Energy Berhad SIRIM Berhad (Renewable
Energy Research Centre) SIRIM Berhad (Secretariat) Suruhanjaya
Tenaga The Electrical and Electronics Association of Malaysia TNB
Energy Services Sdn Bhd Universiti Kebangsaan Malaysia Universiti
Malaya Universiti Teknologi Malaysia Universiti Teknologi MARA
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MS 1837:2010
iv © STANDARDS MALAYSIA 2010 - All rights reserved
FOREWORD This Malaysian Standard was developed by the Working
Group on Solar Photovoltaic Systems under the authority of the
Industry Standards Committee on Generation, Transmission and
Distribution of Energy. This Malaysian Standard is the first
revision of MS 1837, Installation of grid-connected photovoltaic
(PV) system. Major modifications in this revision are as follows:
a) incorporation of new clauses on “Terms and definitions”; b)
incorporation of new figures on “General requirements” in Clause 4;
c) incorporation of new requirements on “Over-voltage protection”
in 5.8;
d) incorporation of new requirement on “PV array and PV
sub-array connection boxes” in
7.3; e) incorporation of new requirement on “Fuses” in 7.5; and
f) incorporation of Annex D on “Changes between MS 1837:2005 and MS
1837:2010 (First
revision)”. This Malaysian Standard cancels and replaces MS
1837:2005. Compliance with a Malaysian Standard does not of itself
confer immunity from legal obligations.
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MS 1837:2010
© STANDARDS MALAYSIA 2010 - All rights reserved 1
INSTALLATION OF GRID-CONNECTED PHOTOVOLTAIC (PV) SYSTEM (FIRST
REVISION)
1 Scope This Malaysian Standard sets out the general
installation requirements for grid-connected photovoltaic (PV)
arrays with direct current (DC) open circuit voltages up to 1 000 V
between positive and negative conductors or up to ± 1 000 V with
respect to earth. NOTES: 1. This includes the following PV array
configurations: a) single string of modules; b) multi-string PV
array; and c) PV array divided into several sub-arrays. 2. DC
systems and photovoltaic systems in particular, pose some hazards
in addition to those derived from conventional alternate current
(AC) power systems, including the ability to produce and sustain
electrical arcs with currents that are not much greater than normal
operating currents. This standard addresses the safety requirements
arising from the particular characteristics of photovoltaic
systems. Those characteristics are presented in Annex A. The
objective of this standard is to provide guidelines on
grid-connected PV system installation, electrical safety and fire
protection requirements for: a) uninformed persons, including
owner(s)/occupier(s) and users of the premises where
photovoltaic arrays are installed; b) informed PV service
providers and workers (e.g. electricians) working on these
systems;
and c) emergency workers. 2 Normative references The following
normative references are indispensable for the application of this
standard. For dated references, only the edition cited applies. For
undated references, the latest edition of the normative reference
(including any amendments) applies. MS 589, Specification for 13 A
plugs, socket-outlets, adaptors and connection units MS 981,
Specification for safety signs and colours: Colour and design MS
982, Specification for fire safety signs, notices and graphic
symbols MS 1992, Electronic equipment for use in power
installations MS IEC 60364, Electrical installation of buildings MS
IEC 60364-7-712, Electrical installations of buildings - Part
7-712: Requirements for special installations or locations - Solar
photovoltaic (PV) power supply systems MS IEC 60529, Degrees of
protection provided by enclosures (IP code)
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MS 1837:2010
2 © STANDARDS MALAYSIA 2010 - All rights reserved
MS IEC 61000-3-2, Electromagnetic compatibility (EMC) - Limits
for harmonic current emissions (equipment input current ≤ 16 A per
phase) MS IEC 61000-6-3, Electromagnetic compatibility (EMC) - Part
6-3: Generic standards - Emission standard for residential,
commercial and light-industrial environments MS IEC 61000-6-4,
Electromagnetic compatibility (EMC) - Part 6-4: Generic standards -
Emission standard for industrial environments MS IEC 61215,
Crystalline silicon terrestrial photovoltaic (PV) modules - Design
qualification and type approval MS IEC 61643-1, Low-voltage surge
protective devices - Part 1: Surge protective devices connected to
low-voltage power distribution systems - Requirements and tests MS
IEC 61643-12, Low voltage surge protective devices - Part 12: Surge
protective devices connected to low voltage power distribution
systems - Selection and application principles MS IEC 61646,
Thin-film terrestrial photovoltaic (PV) modules - Design
qualification and type approval MS IEC 61727, Photovoltaic (PV)
systems - Characteristics of the utility interface MS IEC 61730-1,
Photovoltaic (PV) module safety qualification - Part 1:
Requirements for construction MS IEC 61730-2, Photovoltaic (PV)
module safety qualification - Part 2: Requirements for testing MS
IEC 62305-1, Protection against lightning - Part 1: General
principles IEEE 1547, Standard for interconnecting distributed
resources with electric power systems IEEE 1547.1, Standard for
conformance tests procedures for equipment interconnectivity
distributed resources with electric power systems 3 Terms and
definitions For the purposes of this standard, the following terms,
definitions and abbreviations apply. 3.1 accessible, readily
Capable of being reached quickly and without climbing over or
removing obstructions, mounting upon a chair, or using a movable
ladder, and in any case not more than 2.0 m above the ground, floor
or platform. 3.2 available, readily Capable of being reached for
inspection, maintenance or repairs without necessitating the
dismantling of structural parts, cupboards, benches or the
like.
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MS 1837:2010
© STANDARDS MALAYSIA 2010 - All rights reserved 3
3.3 AC side Part of the PV system from the AC terminals of the
inverter until the grid connection to the mains. 3.4 by-pass diode
A diode that is connected in parallel with a number of PV cells or
the whole PV module. 3.5 cable A single cable core, or two or more
cable cores laid up together, either with or without fillings,
reinforcements, or protective coverings. 3.6 cable, shielded A
cable with surrounding earthed metallic layer to confine the
electric field within the cable and/or to protect the cable from
external electrical influence. NOTE. Metallic sheaths, armours and
earthed concentric conductors may also serve as shields. 3.7 cable
core The conductor with its insulation but not including any
mechanical protective covering. 3.8 Class II equipment Equipment in
which protection against electric shock does not rely on basic
insulation only, but in which additional safety precautions such as
double insulation or reinforced insulation are provided, there
being no provision for protective earthing or reliance upon
installation conditions. Such equipment may be one of the following
types: a) Equipment having durable and substantially continuous
enclosures of insulating material
which envelops all metal parts, with the exception of small
parts, such as nameplates, screw and rivets, which are isolated
from live parts by insulation at least equivalent to reinforced
insulation; such equipment is called insulation-encased Class II
equipment.
b) Equipment having a substantially continuous metal enclosure,
in which double insulation
is used throughout, except for those parts where reinforced
insulation is used, because the application of double insulation is
manifestly impracticable; such equipment is called metal-encased
Class II equipment.
c) Equipment that is a combination of the types described in 3.8
a) and 3.8 b). NOTES: 1. The enclosure of insulation-encased Class
II equipment may form part of the whole of the supplementary
insulation or of the reinforced insulation. 2. If the equipment
with double insulation or reinforced insulation throughout has an
earthing terminal or earthing contact, it is considered to be of
Class I construction. 3. Class II equipment may be provided with
means for maintaining the continuity of protective circuits,
insulated from accessible conductive parts by double insulation or
reinforced insulation. 4. Class II equipment may have parts
operating at SELV (separated extra low voltage).
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MS 1837:2010
4 © STANDARDS MALAYSIA 2010 - All rights reserved
3.9 connection box An enclosure where cables are joined and/or
connected to electrical equipment and/or protective devices. 3.10
DC side Part of the PV system from the PV cell to the DC terminals
of the inverter. 3.11 installation earthing When a PV array is
installed on a building, the installation earthing is the earthing
bar or earthing rod of the building. 3.12 inverter A system that
converts the electrical power delivered by the PV array into the
appropriate frequency and/or voltage to be delivered to the load,
and/or injected into the electricity grid. 3.13 ISC STC MOD The
short circuit current of a PV module or PV string at standard test
conditions (STC), as specified by the manufacturer on the product
specification plate. NOTE. As PV strings are a group of PV modules
connected in series, the short circuit current of a string is equal
to ISC STC MOD. 3.14 ISC STC S-ARRAY The short circuit current of a
PV sub-array at STC, and is equal to:
ISC STC S-ARRAY = ISC STC MOD X NP SA where NP SA is the number
of parallel-connected PV strings in the PV sub-array. 3.15 ISC
ARRAY The short circuit current of the PV array at STC, and is
equal to: ISC STC ARRAY = ISC STC MOD x NP A where NP A is the
total number of parallel-connected PV strings in the PV array. 3.16
live part A conductor or conductive part intended to be energised
in normal use. 3.17 PARRAY STC The nominal power of the PV array
calculated as the sum of the nameplate power ratings of all the PV
modules that constitute the array.
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MS 1837:2010
© STANDARDS MALAYSIA 2010 - All rights reserved 5
3.18 PVAC module Combination of a PV module with an integrated
DC/AC inverter, whereas the connection is available on the AC side
only. The DC cannot be accessed. 3.19 PV array An electrically
integrated assembly of PV modules, and other necessary components,
to form a DC power supply unit. A PV array may consist of a single
PV string, or several parallel-connected strings, or several
parallel-connected PV sub-arrays and their associated electrical
components. The boundary of a PV array is the connection of the PV
array cable to a piece of equipment that forms part of the inverter
and which is dedicated to that particular PV array. Two or more PV
arrays, which are not interconnected in parallel on the generation
side of the inverter, is to be considered as independent PV arrays.
3.20 PV array cable The output cable of a PV array that connects
the PV array connection box to the inverter. 3.21 PV array,
isolated A PV array where there is electrical separation between
the PV array output circuit and the AC system. NOTE. Electrical
separation of power circuits is usually achieved by means of a
power transformer. 3.22 PV array connection box An enclosure where
all the PV strings of a PV array or all the PV sub-arrays of a PV
array are electrically connected in parallel and where protection
devices may be located, if necessary. 3.23 PV array open circuit
voltage The PV array open circuit voltage is considered to be equal
to VOC STC ARRAY (see 3.39). NOTE. The open circuit voltage is
dependent on the cell temperature. 3.24 PV cell The basic unit of
photovoltaic conversion; a semiconductor device that can convert
light directly into electrical energy. 3.25 PV kWh meter A kWh
meter which records kWh units of AC electricity generated by a PV
system. 3.26 PV module An assembly of several PV cells electrically
connected to form a larger photovoltaic conversion device, and
which are encapsulated together to protect them from the
environment. A PV module is the smallest ready-to-use photovoltaic
conversion device. 3.27 PV module connection box An enclosure
affixed to a PV module, where the electrical connections to the PV
module are made.
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MS 1837:2010
6 © STANDARDS MALAYSIA 2010 - All rights reserved
3.28 PV string A circuit formed by one or more series connected
PV modules. The series connection of PV modules to form a PV string
is intended to provide the required circuit voltage. 3.29 PV string
cable A cable connecting the modules in a PV string, or connecting
the string to a junction box or to the DC terminals of the
inverter. 3.30 PV sub-array A group of PV strings connected in
parallel, that comprise a partial section of the PV array, where
the output current of that group of strings is carried by a
dedicated output cable before being connected in parallel with
other sub-arrays. NOTE. Not all PV arrays are divided into
sub-arrays. 3.31 PV sub-array cable The output cable of a PV
sub-array that carries only the output current of its associated
sub-array in normal operation, and that connects the PV sub-array
with the other PV sub-array that constitute the PV array. NOTE. PV
sub-array cables are only relevant for PV arrays that are divided
into sub-arrays. 3.32 PV sub-array connection box An enclosure
where all the PV strings of a PV are electrically connected in
parallel and where protection devices may be located if necessary.
NOTE. PV sub-array junction boxes are only relevant for PV arrays
that are divided into sub-arrays. 3.33 PV system An electrically
integrated assembly of PV array, inverter (or power conditioning
unit) and other necessary components to form a power generation
unit. 3.34 ripple-free DC For sinusoidal ripple voltage, a ripple
content not exceeding 10 % r.m.s. NOTE. Therefore the maximum peak
value does not exceed 140 V for a nominal 120 V ripple-free DC
system and 70 V for a nominal 60 V ripple-free DC system. 3.35 SELV
(separated extra-low voltage) An extra-low voltage system which is
electrically separated from earth, and from other systems, in such
a way that a single fault cannot give rise to the risk of electric
shock. 3.36 SPD (surge protective device) A device that is intended
to limit transient over-voltages and divert surge currents. It
contains at least one non-linear component.
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© STANDARDS MALAYSIA 2010 - All rights reserved 7
3.37 STC (standard test conditions) A standard set of reference
conditions used for the testing and rating of photovoltaic cells
and modules. The standard test conditions are: a) PV cell
temperature of 25 °C; b) irradiance in the plane of the PV cell or
module of 1 000 W/m2; and c) light spectrum corresponding to an
atmospheric air mass of 1.5. 3.38 VOC STC MOD The open circuit
voltage of a PV module at STC, as specified by the manufacturer in
the product specification. 3.39 VOC STC ARRAY The open circuit
voltage at STC of a PV array, and is equal to: VOC STC ARRAY = VOC
STC MOD x Ns where Ns is the number of series-connected PV modules
in any PV string of the PV array. NOTE. This standard assumes that
all strings within a PV array are connected in parallel; hence the
open circuit voltage of PV sub-arrays and PV strings is equal to
VOC STC ARRAY. 3.40 voltage Differences of potential normally
existing between conductors and between conductors and earth are as
follows: a) extra-low voltage (ELV) - Not exceeding 50 V AC or 120
V ripple-free DC; and
b) low voltage (LV) - Exceeding extra-low voltage, but not
exceeding 1 000 V AC or 1 500 V
DC. NOTE. When calculating the voltage of a PV array, VOC STC
ARRAY is to be used. 4 General requirements The installation of a
grid-connected PV system shall be in accordance with Figure 1 and
Figure 2. These figures shall be extensively referred to throughout
this standard. 5 Protection requirements 5.1 General The
installation of grid-connected PV systems shall comply with the
requirements of MS IEC 60364 or MS IEC 60364-7-712. The provisions
of this section are aimed at ensuring that these requirements are
met, taking into account a range of system topologies and earthing
arrangements.
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MS 1837:2010
8 © STANDARDS MALAYSIA 2010 - All rights reserved
5.2 By-pass diodes By-pass diodes shall be used in the PV
modules. If by-pass diodes are not embedded in the PV module
encapsulation, they shall comply with all the following
requirements: a) have a voltage rating at least 2 x VOC STC MOD of
the protected module; b) have a current rating of at least 1.3 x
ISC STC MOD; c) be installed according to the module manufacturer’s
recommendations; d) be installed so no live parts are exposed; and
e) be protected from degradation due to environmental factors.
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9
MS 1837:2010
Figure 1. Schematic diagram of a grid-connected PV system
(single-phase)
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MS 1837:2010
Figure 2. Schematic diagram of a grid-connected PV system
(three-phase)
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5.3 Over-current protection 5.3.1 Discrimination Over-current
protection within the PV string shall be graded in such a way that
lower level protection trips first in the event of fault currents
flowing from higher current sections to lower current sections of
the PV array. NOTE. When circuit breakers with over-current
protection elements are used, they also provide the disconnecting
means required in 5.4. 5.3.2 PV strings In cases where it applies
(see Figure 1 and 2), all PV strings shall be protected with an
over-current protection device with load breaking disconnecting
facilities. These over-current protection devices shall be
installed in positive active conductors. Suitably rated
circuit-breakers used for over-current protection may also provide
load breaking disconnecting facilities (see 5.4). The rated trip
current (ITRIP) of over-current protection devices for PV strings
shall be as specified by the PV module manufacturer or, ITRIP shall
be determined by the following formula:
1.5 x ISC STC MOD ≤ ITRIP ≤ 2 x ISC STC MOD 5.3.3 PV array and
PV sub-arrays Over-current protection device is not required for PV
array and PV sub-arrays. 5.4 Disconnecting means 5.4.1 General
Disconnecting means shall be provided in PV arrays according to
5.4.2, to isolate the PV array from the inverter and vice versa and
to allow for maintenance and inspection tasks to be carried out
safely. NOTE. This clause does not apply to module inverters where
the inverter is an integral part of the PV module. 5.4.2 Selection
and installation Only device with DC rating which is able to
extinguish electrical arc shall be used. Suitably rated
circuit-breakers used for over-current protection may also provide
load breaking disconnecting facilities. Other disconnection and
isolation devices having the characteristics described in 7.4 may
be used as a disconnection means. Fuse systems used for string
over-current protection are acceptable non-load breaking
disconnecting means if they have removable fusing elements,
preferably with a disconnection mechanism (fuse-combination
unit).
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5.4.2.1 PV strings and PV sub-arrays No separate disconnection
device is required if suitably rated circuit breakers are used for
the over-current protection which also provides load breaking
disconnecting facilities. 5.4.2.2 PV array A readily available
load-breaking disconnection device, which interrupts both positive
and negative conductors, shall be installed in the PV array cable.
This device shall be lockable in the off position. 5.4.2.3 Inverter
A suitably AC rated and readily available load-breaking
disconnection device, which interrupts both positive and negative
conductors, shall be installed in the cable connected to the
inverter AC terminal. This device shall be lockable in the off
position. 5.5 Emergency switching device The PV array (DC)
load-breaking disconnection device and the inverter (AC)
load-breaking disconnection device shall be used as the emergency
switching devices, and therefore shall be readily accessible and be
clearly identified according to 9.4.2. The emergency switching
device shall comply with the requirements for devices for emergency
switching including emergency stopping as contained in MS IEC 60364
or MS IEC 60364-7-712. If the emergency switching device is
manually operated, the remote operating device shall be located in
a readily accessible point and be identified in accordance with
9.4.2. 5.6 Earth fault protection All metal casings and frames
shall be earthed according to MS IEC 60364 or MS IEC 60364-7-712.
5.7 Lightning protection Lightning protection measures may be
required in some PV installations. The need for lightning
protection shall be assessed in accordance with MS IEC 62305-1. A
lightning protection system has the task of preventing severe
damage caused by fire or mechanical destruction if a direct
lightning strike occurs on a building or structure. Lightning
protection systems consist of three essential components: a) an air
termination system, consisting of metallic masts or rods of
sufficient height to divert
lightning currents through their structure; b) a down conductor
of sufficient cross-sectional area to conduct lightning currents to
earth;
and c) an earth termination system.
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For ground mounted or freestanding PV arrays, the need for a
lightning protection system shall be assessed in accordance with MS
IEC 62305-1, and if required, it shall be installed in compliance
with that standard. The installation of a PV array on a building
has a negligible effect on the probability of direct lightning
strikes and therefore it does not necessarily imply that a
lightning protection system shall be installed if none is already
present. However, if the physical characteristics or prominence of
the building do change significantly due to the installation of the
PV array, it is required that the need for a lightning protection
system be assessed in accordance with MS IEC 62305-1, and if
required, it shall be installed in compliance with that standard.
If a lightning protection system is already installed on the
building, it shall be verified that the PV array and associated
equipment are within the protection zone of the system in
accordance with MS IEC 62305-1. If the PV array is not within the
protection zone of the existing lightning protection system,
additional air termination(s) shall be provided in accordance with
MS IEC 62305-1. When a PV array is protected by a lightning
protection system, the metal structure of the PV array shall be
bonded to the lightning protection system, unless the minimum
safety clearances as specified in MS IEC 62305-1, can be achieved.
5.8 Over-voltage protection Over-voltage protection measures
include: a) equipotential bonding; b) avoidance of wiring loops; c)
installation of SPDs; and d) shielding. 5.8.1 Wiring loops To
reduce the magnitude of lightning induced over-voltages, the PV
array wiring shall be laid in such a way that the area of
conductive loops is minimum (see example in Figure 3). 5.8.2 Surge
protective device (SPD) 5.8.2.1 General guide SPDs are a very
common method of protecting electrical systems and equipment
against over-voltages. When these devices are used, the
recommendations of MS IEC 61643-12 shall be observed. Many
commercial PV inverters are fitted with SPDs on the PV input (DC)
terminals, and this shall be considered when specifying the
over-voltage protection of the PV array.
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5.8.2.2 Selection The selection of SPDs shall be in accordance
to MS IEC 61643-12. 5.8.2.3 Usage and installation The usage and
installation of SPDs shall be in accordance to MS IEC 61643-12. The
SPDs on the DC side shall be installed closest possible to the
inverter. 5.8.2.4 SPD specifications to protect PV array and
inverter (DC terminal) The specifications for SPDs to protect PV
arrays and inverter (DC terminal) are as follows (refer to list of
parameters for SPDs selection in MS IEC 61643-12): a) SPDs of Class
II (in this context, Class II refers to the test specifications of
SPDs rather
than insulation class). b) Have a maximum continuous operating
voltage (Uc) with Uc > VOC STC GEN. c) Have a maximum discharge
current (Imax) (8/20 μs) with Imax > 40 kA (or at least 20
kA).
d) Have a nominal discharge current (In) (8/20 μs) with In >
20 kA (or at least 10 kA). e) Have a voltage protection level (Up)
with 1.3 x VOC STC GEN < Up < 1.1 kV.
f) Have a voltage protection level at In (Up) with Up (L-PE)
< 2.5 kV. 5.8.2.5 SPDs specifications to protect inverter (AC
terminal) The specifications for SPD to protect inverter (AC
terminal) shall be suitably rated for AC use and in accordance to
MS IEC 61643-12 and in conjunction with MS IEC 61643-1. 5.8.3
Shielding When the PV array frame is bonded to a lightning
protection system, the PV array cable shall be shielded by one of
the following methods, and the shielding conductor shall be
connected to earth at both ends: a) with a metallic cable armour or
shield with an equivalent cross-sectional area of 10 mm2
Cu; or b) with a metallic conduit suitable as a bonding
conductor; or c) with an equipotential bonding conductor with a
cross-sectional area of at least 6 mm2 . NOTE. 6 mm2 Cu should be
able to withstand 20 kA for 1 ms.
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6 Wiring requirements 6.1 Compliance with wiring standards The
wiring to the PV array shall comply with the requirements of MS IEC
60364 or MS IEC 60364-7-712. NOTE. Particular attention needs to be
given to the protection of wiring systems against external
influences. 6.2 System voltage VOC STC ARRAY shall not exceed the
maximum allowed system voltage of the PV modules (as specified by
the manufacturer). 6.3 Wiring Installation 6.3.1 General Wiring of
PV arrays shall be laid in such a way that the possibility of line
to line and line to earth faults occurring is minimised. All
connections shall be verified for tightness and polarity during
installation to reduce the risk of faults and possible arcs
occurring during commissioning and operation. 6.3.2 Wiring loops
The PV array wiring should be laid in such a way that the area of
conductive loops is minimised (e.g. by laying cables in parallel as
shown in Figure 3); see also 5.8.1.
Figure 3. PV string wiring with minimum loop area
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6.3.3 String, sub-array and array wiring The wiring of PV
strings, sub-arrays and array shall satisfy the following
requirements: a) Double insulated, DC rated, UV resistant, flex
type and fire retardant shall be used. b) Cables shall be protected
from mechanical damage. c) Cables shall be clamped (to relieve
tension and to prevent conductors coming free from
the connection). 6.3.4 Wiring installation in connection boxes
The following provisions apply to the installation of wiring
systems in connection boxes: a) Where conductors enter a connection
box without conduit, a tension relief system shall be
used to avoid cable disconnections inside the connection box
(for example by using a gland connector).
b) All cable entries, when installed, shall maintain the IP
rating of the enclosure.
NOTE. Water condensation inside connection boxes may be a
problem in some locations and provision may need to be provided to
drain water build-up.
c) The wiring and its insulation particularly through the
connection box including terminal
points shall maintain double insulation status over its entire
length. 6.3.5 Location of PV array and PV sub-array connection
boxes PV array and PV sub-array connection boxes, where installed,
shall be readily available. 6.4 Cable selection 6.4.1 Cable size
6.4.1.1 General Cable sizes for PV string cables, PV sub-array
cables and PV array cables shall not be less than 2.5 mm2 and shall
be determined with regard to both, the minimum current capacity
(see 6.4.1.2) and maximum voltage drop requirements (see 6.4.1.3).
The larger cable size obtained from these two criteria shall be
applied. 6.4.1.2 Current carrying capacity (CCC) The minimum cable
sizes for PV array wiring, based on CCC, shall be based upon a
current rating according to Table 1.
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Table 1. Current rating of PV array circuits
Type of cable Minimum current upon which cable cross-sectional
area should be chosen
PV string cable 2 x ISC STC MOD
PV sub-array and array cable
1.3 x ISC STC S-ARRAY or ARRAY (of relevant array)
NOTE. The operating temperature of PV modules and consequently
their associated wiring can be significantly higher than the
ambient temperature. A minimum temperature rise above maximum
expected ambient temperature of +40 °C should be considered for
cables installed near or in contact with PV modules. 6.4.1.3
Voltage drop The voltage drop between the PV array and the inverter
shall be less than 5 %. NOTE. Voltage drop in cables is a measure
of the losses in PV array wiring and hence affects the efficiency
of the PV power system. 6.4.2 Insulation The insulation of cables
used within the PV array shall: a) have a voltage rating of at
least 1.2 x VOC STC ARRAY;
NOTE. The use of double insulated and shielded cable is required
for wiring of PV arrays where VOC STC ARRAY ≥ 120 V DC, to minimise
the risk of faults within the wiring.
b) have a temperature rating according to the application;
and
NOTE. PV modules frequently operate at temperatures of the order
of 40 °C above ambient temperature. Cable insulation of wiring
installed in contact with, or near, PV modules needs to be rated
accordingly.
c) be UV resistant, or be protected from UV light by appropriate
protection (e.g. installed in
UV resistant conduit). 6.5 Wiring identification Appropriate
identification shall be provided for PV array cabling where it can
be confused with other wiring systems. 7 Component requirements 7.1
PV modules 7.1.1 Reliability Crystalline silicon PV modules shall
comply with MS IEC 61215. Thin film PV modules shall comply with MS
IEC 61646. 7.1.2 Equipment class PV modules shall be Class II. PV
modules shall comply with MS IEC 61730-1 and MS IEC 61730-2.
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7.1.3 Reverse current PV modules shall be capable of conducting
continuously a reverse current equal to 2.6 x ISC MOD without
damage. 7.2 Inverter requirements Inverters shall comply with
requirements in accordance to MS IEC 61000-3-2, MS IEC 61000-6-3,
MS IEC 61000-6-4, MS IEC 60364-7-712 and MS 1992 or IEEE 1547 and
IEEE 1547.1 or other equivalent standard. Inverters shall be
isolated in the event of mains supply failure. 7.3 PV array and PV
sub-array connection boxes 7.3.1 Environmental effects PV array and
PV sub-array connection boxes exposed to the environment shall be
at least IP 56 compliant in accordance with MS IEC 60529, and shall
be UV resistant. 7.4 Switching devices 7.4.1 General All switching
devices shall comply with all the following requirements: a) be
rated for AC side as AC and be rated for DC side as DC use and able
to extinguish
electrical arcs; b) have a voltage rating greater than VOC STC
ARRAY; c) not have exposed metallic live parts in connected or
disconnected state; and d) interrupt all poles. 7.4.2 Current
breaking devices In addition to the requirements of 7.4.1, circuit
breakers and any other load breaking disconnection devices used for
protection and/or disconnecting means shall comply with the
following requirements: a) not be polarity sensitive (as fault
currents in a PV array may flow in the opposite direction
of normal operating currents); b) be rated to interrupt full
load and prospective fault currents from the PV array and any
other connected power sources such as batteries, generators and
the grid, if present; and c) when over-current protection is
incorporated, the trip current shall be rated according to
5.3. 7.4.3 Plugs, sockets and couplers Plugs, sockets and
couplers shall comply with all the following requirements: a) be
rated for AC side for AC use and be rated for DC side for DC
use;
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b) have a voltage rating greater than VOC STC ARRAY; c) be
protected from contact with live parts in both the connected and
disconnected state
(i.e. be shrouded); d) have a current rating equal to, or
greater than, the cable to which they are fitted; e) require a
deliberate force to disconnect; f) have a temperature rating
suitable for their installation location; g) if multipolar, be
polarised; h) comply with Class II; and i) if exposed to the
environment, be rated for outdoor use, be UV resistant and be at
least
IP 56 compliant. Plugs and socket outlets normally used for
connection to AC mains power as described in MS 589, shall not be
used in PV arrays wiring. 7.5 Fuses Fuses used in PV arrays shall
comply with all the following requirements: a) be rated for AC for
AC use and be rated for DC for DC use; b) have a voltage rating
equal to, or greater than VOC STC ARRAY; c) be rated to interrupt
full load and prospective fault currents from the PV array and
connected power sources such as batteries, generators and the
grid, if present; and
d) have a current rating of ≥ 1.5 and ≤ 2 time ISC STC String.
NOTE. When fuses are provided for over-current protection, the use
of fused load break switch-disconnectors (fuse-combination units)
is recommended. 7.5.1 Fuse holders Fuse holders shall comply with
all the following requirements: a) have a voltage rating equal to,
or greater than VOC STC ARRAY; b) have a current rating equal to,
or greater than, the corresponding fuse; and c) provide a degree of
protection not less than IP 2X. 7.6 PV kWh meter The PV kWh meter
is used to record kWh units of AC generated electricity by a PV
system. The meter shall be connected between the AC breaker and the
AC grid isolator main switch (AC load breaking disconnection
device).
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The PV kWh meter shall be suitable to record kWh units of AC
electricity. The meter accuracy shall be of Class 2 (± 2 %). 8
Earthing 8.1 General There are three possible reasons for earthing
a PV array: a) equipotential bonding to avoid uneven potentials
across and installation; b) protective earthing to provide a path
for fault currents to flow; and c) lightning protection. An earth
conductor may perform one or more of these functions in an
installation. The dimensions and location of the conductor are very
dependent on its function. 8.2 Earthing electrode If a separate
earthing electrode is provided for the PV array, this electrode
shall be bonded to the installation earthing. 8.3 Equipment
earthing 8.3.1 Earthing of equipment Equipment earthing refers to
the bonding to earth of all frames of the PV array including any
structural metalwork. Equipment earthing shall be done with at
least a 10 mm2 earthing conductor. 8.3.2 Earthing conductors All PV
array earthing conductors shall comply with the material, type,
insulation, identification, installation and connection
requirements as specified in MS IEC 60364 or MS IEC 60364-7-712. 9
Marking requirements 9.1 General All signs required by 9.2 to 9.4
shall: a) comply with MS 981 and MS 982; b) be indelible; c) be
legible from at least 0.8 m unless otherwise specified in the
relevant clauses; and d) be constructed and affixed to remain
legible for the life of the equipment it is attached or
related to. NOTE. Examples of signs are given in Annex B.
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9.2 PV array and PV sub-array connection boxes A sign containing
the text 'PV DC' shall be attached to PV array and PV sub-array
connection boxes. 9.3 Disconnection devices 9.3.1 General
Disconnection devices shall be marked with an identification name
or number in accordance with the PV array wiring diagram. All
switches shall have the ON and OFF positions clearly indicated.
9.3.2 PV array main switch The PV array main switch (DC load
breaking disconnection device) shall be provided with a sign
affixed in a prominent location with the following text: ‘PV DC
MAIN SWITCH’. 9.3.3 Inverter main switch The inverter main switch
(AC load breaking disconnection device) shall be provided with a
sign affixed in a prominent location with the following text: ‘PV
AC MAIN SWITCH’. 9.4 Fire emergency information 9.4.1 General For
PV arrays that are installed on buildings and have a rated power
greater than 500 W or with VOC STC ARRAY greater than 50 V, a sign
next to the building main switchboard shall be provided. This sign
shall specify the procedure for the fire brigade to enter the
building without the risk of electric shock from the PV array and
the operation of the emergency switching device, if relevant. This
sign shall be legible from at least 1.5 m. 9.4.2 Manually operated
emergency switching device When a manually operated switching
device is used, the means of operating such device, such as handles
or push-buttons for emergency switching, shall be clearly
indicated. The signs to identify the switching devices (see 9.3.2
and 9.3.3) shall be placed next to them and shall be legible from
at least 1.5 m. 9.5 Shutdown procedure A sign, that contains
shutdown instructions for the PV system, shall be located in a
prominent location. The sign shall include the name and location of
the relevant disconnection devices. The sign shall also include the
following PV array information: a) open circuit voltage at STC; and
b) short circuit current at STC.
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10 Documentation The PV system installer shall prepare the
following documents and a copy shall be handed to the PV system
owner: a) a basic circuit diagram that includes the electrical
ratings of the PV array, including the
information required by 9.4; b) a copy of the emergency shutdown
procedure including the location of relevant switching
devices; c) as-built drawing that includes the PV array, the
inverter and the major components; d) PV system or parts
certification as required by relevant authorities and provided
by
manufacturer; e) all specifications of the PV array, the
inverter and the system components; and f) PV system maintenance
requirements (see Annex C). 11 Commissioning 11.1 General
Commissioning tests are required to ensure that the PV array
complies with the safety requirements of this standard. 11.2 Wiring
and installation integrity The PV array wiring shall be inspected
for compliance with the wiring requirements of MS IEC 60364 or MS
IEC 60364-7-712, and the wiring requirements set out in Clause 4 of
this standard, and corrected if necessary. 11.3 Open circuit
voltage 11.3.1 General This test is intended to ensure that wiring
polarity and continuity of the PV array are correct. 11.3.2
Procedure The open circuit voltage of every string shall be
measured before connecting to other strings. All PV string open
circuit voltages shall be within 5 % variation; otherwise the
connections shall be verified for polarity, continuity and possible
faults and repaired. Once the verification is complete and
satisfactory, the PV strings can be connected in parallel. The same
procedure shall be carried out to verify PV sub-array open circuit
voltages (if relevant) and PV array open circuit voltage before
connecting the PV array to the inverter. NOTE. It is recommended
that all measurements are made under irradiance conditions (during
the daytime with no rain).
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11.4 PV kWh meter The meter shall be tested for functionality
and the initial value shall be recorded. 11.5 Commissioning records
The following commissioning records shall be given to the owner,
and if necessary to the relevant authorities: a) a certificate
stating that the work done on the installation meets the
requirements of this
standard; b) a record of the final open circuit voltage
measurements; c) a record of the measured values of current and/or
resistance before and after any
adjustments to the earth fault protection system (if relevant);
and d) a record of the initial value of the PV kWh meter.
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Annex A (informative)
Characteristics of PV arrays
A1 PV arrays A1.1 DC versus AC behavior One of the most
important characteristics of direct current (DC) in relation to
safety is that DC arcs, caused by switching or faults, are much
more difficult to extinguish than AC arcs. This implies that all
switchgear and over-current protection devices in the PV array need
to be rated for used in DC circuits (DC switchgear is less readily
available and its cost increases significantly, as the DC operating
voltages increase). A1.2 Series parallel configuration To reduce
mismatch and improve PV array yield, all PV strings within a PV
array should be of the same technology and have the same number of
series connected PV modules. Also, all PV modules within the PV
array should have similar rated electrical characteristics
including short circuit current, open circuit voltage, maximum
power current, maximum power voltage and rated power (all at STC).
A1.3 Low fault levels PV cells (and consequently PV arrays) behave
like current sources under low impedance faults. Thus in PV arrays
without battery storage, currents much greater than normal full
load currents will not flow even under short circuit fault
conditions, making short circuit detection impossible. Therefore,
electric arcs can be formed in a PV array with fault currents that
will not trip an over-current device. The implications for PV array
design that arise from these PV array characteristics are: a) the
chances of line to line faults, earth faults and inadvertent wire
disconnections in the
system need to be minimised; and b) earth fault detection and
disablement could be required as part of the system protection
functions depending on the array size and location, to eliminate
the risk of fire. A1.4 Operating temperature PV modules can operate
well above ambient temperature under normal operating conditions. A
common steady state temperature rise for silicon modules operating
at the maximum power point under 1 000 W/m2 solar irradiance and
with adequate ventilation is 25 °C. This temperature rise can go up
by 35 °C when modules are open circuited (i.e. the PV array has
been put out of operation due to a grid failure in the case of grid
connected systems). The temperature rise can be even higher when
irradiance levels are greater than 1 000 W/m2 and when modules have
poor ventilation. The following are two main requirements on the PV
array design derived from this operating characteristic of PV
modules:
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© STANDARDS MALAYSIA 2010 - All rights reserved 25
a) PV module efficiency reduces as their operating temperature
increases (for crystalline
silicon solar cells the maximum power decreases between 0.4 %
and 0.5 % per each degree C rise in operating temperature).
Therefore adequate ventilation of the PV array should be a design
goal, in order to ensure optimum performance for both modules and
associated components.
b) All the components and equipment that may be in direct
contact or near the PV array
(conductors, inverters, connectors, etc.) need to be capable of
withstanding the expected maximum operating temperature of the PV
array.
A2 Grid-connected photovoltaic (PV) systems The systems have the
following characteristics: a) Generally they do not use batteries
for energy storage because the grid behaves as an
infinite bus that can receive or supply power. b) PV arrays in
these systems tend to be low voltage. c) A wide range of inverter
topologies can be found on the market. Some of them include an
isolation transformer, and some of them are transformerless;
some of them require the PV array to be earthed and some of them
require it not to be earthed.
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Annex B (informative)
Examples of signs B1 Overview This annex provides examples of
appropriate signs as specified in Clause 9.
Figure B1. Example of sign required on PV array connection box
(9.2)
Figure B2. Example of sign required adjacent to PV array main
switch (9.3.2)
Figure B3. Example of sign required adjacent to inverter main
switch (9.3.3)
PV DC
PV DC
MAIN SWITCH
PV AC
MAIN SWITCH
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Figure B4. Example of fire emergency information sign required
on the main
switchboard (9.4.1)
FIRE EMERGENCY INFORMATION
DISCONNECT THE GRID MAINS POWER INTO THE BUILDING BEFORE
ENTERING THE PREMISE. THIS WILL ALSO DISCONNECT THE PV SYSTEM POWER
SUPPLY INTO THE BUILDING
FOLLOW THE PV SYSTEM SHUTDOWN PROCEDURE TO FULLY DISCONNECT
THE PV SYSTEM
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28 © STANDARDS MALAYSIA 2010 - All rights reserved
Figure B5. Example of shutdown procedure (9.5)
PV SYSTEM SHUTDOWN PROCEDURE
STEP 1: Turn off the ‘PV AC MAIN SWITCH’ located next to the AC
terminals of the inverter.
STEP 2: Turn off the ‘PV DC MAIN SWITCH’ located
next to the DC terminals of the inverter.
Warning: Do not open plug and socket connectors or PV string
isolators under load
PV Array Open Circuit Voltage at STC: VDC PV Array Short Circuit
Current at STC: ADC
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Annex C (informative)
Maintenance requirements C1 Safety Attention should be given in
the maintenance procedures to the following safety requirements: a)
emergency shutdown procedure; b) obey all warning signs; c) shut
system down and interrupt PV array according to the manual shutdown
procedure; d) split strings into extra low voltage sections (if
relevant); and e) warn of the live parts that cannot be
de-energised during daylight. C2 Periodic maintenance The following
maintenance activities should be considered for inclusions in the
maintenance procedures, according to the location, size and design
of the PV array. a) Cleaning of the PV array might be periodically
required in locations where it is likely to
collect dust or other shading materials. b) Periodic inspections
should be carried out to check wiring integrity, electrical
connections,
corrosion and mechanical protection of wiring. c) Verify open
circuit voltage, and if possible short circuit current values. d)
Verify functioning of earth fault protection (if relevant). e)
Measure wet insulation resistance. f) Check PV array mounting
structure(s). g) Test operation of switches regularly. h) Check for
module defects (fracture, moisture penetration, browning, etc.). i)
Verify status of SPDs (if relevant).
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30 © STANDARDS MALAYSIA 2010 - All rights reserved
C3 Operation and maintenance procedures Operation and
maintenance procedures should include the following: a) a short
description of the function and operation of all installed
equipment. More detailed
information should be available from the manufacturer’s
documentation [see C3 d)]; b) emergency and maintenance shutdown
procedures; c) periodic maintenance requirements including
procedures and schedule; and d) equipment manufacturer’s
documentation (data sheets, handbooks, etc.) for all
equipment supplied.
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MS 1837:2010
Annex D (informative)
Changes between MS 1837:2005 and MS 1837:2010 (First
revision)
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision)
MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No. Additional (A) Or Deletion (D) Amended Text
Foreword Foreword A + D This Malaysian Standard was developed by
the Working Group on Utility Interfaced Solar Photovoltaic System
under the authority of the Electro technical Industry Standards
Committee Compliance with a Malaysian Standards does not of itself
confer immunity from legal obligations. This Malaysian Standard was
developed by the Working Group on Solar Photovoltaic Systems under
the authority of the Industry Standards Committee on Generation,
Transmission and Distribution of Electrical Energy. This Malaysian
Standard is the first revision of MS 1837, Installation of
grid-connected photovoltaic (PV) system. Major modifications in
this revision are as follows: a) incorporation of new clauses on
“Terms and definitions”;
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MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
b) incorporation of new figures on “General requirements” in
Clause 4;
c) incorporation of new requirements on “Over-voltage
protection” in 5.8; d) incorporation of new requirement on “PV
array and PV
sub-array connection boxes” in 7.3; e) incorporation of new
requirement on “Fuses” in 7.5; and
f) incorporation of Annex D on “Changes between MS
1837:2005 and MS 1837:2010 (First revision)”. This Malaysian
Standard cancels and replaces MS 1837:2005. Compliance with a
Malaysian Standard does not of itself confer immunity from legal
obligations.
SECTION 1 1.1 Scope 1.2 Objective
1 Scope
Merged sub clause 1.1 & 1.2
1.3 Normative references
2 Normative references
A + D MS 589, Specification for 13 A plugs, socket-outlets,
adaptors and connection units MS 981, Specification for safety
signs and colours: Colour and design MS 982, Specification for fire
safety signs, notices and graphic symbols
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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33
MS 1837:2010
MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
MS 1992, Electronic equipment for use in power installations MS
IEC 60364, Electrical installation of buildings MS IEC 60364-7-712,
Electrical installations of buildings - Part 7-712: Requirements
for special installations or locations - Solar photovoltaic (PV)
power supply systems MS IEC 60529, Degrees of protection provided
by enclosures (IP code) MS IEC 61000-3-2, Electromagnetic
compatibility (EMC) - Limits for harmonic current emissions
(equipment input current ≤ 16 A per phase) MS IEC 61000-6,
Electromagnetic compatibility (EMC) - Part 6: Generic standards MS
IEC 61024-1, Protection of structures against lightning - Part 1:
General principles MS IEC 61215, Crystalline silicon terrestrial
photovoltaic (PV) modules - Design qualification and type approval
MS IEC 61643-1, Low-voltage surge protective devices - Part 1:
Surge protective devices connected to low-voltage power
distribution systems - Requirements and tests MS IEC 61643-12, Low
voltage surge protective devices - Part 12: Surge protective
devices connected to low voltage power distribution systems -
Selection and application principles
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
MS IEC 61646, Thin-film terrestrial photovoltaic (PV) modules -
Design qualification and type approval MS IEC 61727, Photovoltaic
(PV) systems - Characteristics of the utility interface MS IEC
61730-1, Photovoltaic (PV) module safety qualification - Part 1:
Requirements for construction MS IEC 61730-2, Photovoltaic (PV)
module safety qualification - Part 2: Requirements for testing MS
IEC 62305-1, Protection against lightning - Part 1: General
principles IEEE 1547, Standard for interconnecting distributed
resources with electric power systems IEEE 1547.1, Standard for
conformance tests procedures for equipment interconnectivity
distributed resources with electric power systems
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837:2010
MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
1.4 Definitions 1.4.1 Accessible, readily 1.4.2 Available,
readily
-
1.4.3 By Pass diode 1.4.4 Cable 1.4.5 Cable, shielded 1.4.6
Cable core 1.4.7 Class II equipment 1.4.8 Connection box
- 1.4.9 Installation earthing
3 Terms and definitions 3.1 Accessible, readily 3.2 Available,
readily 3.3 AC side 3.4 By Pass diode 3.5 Cable 3.6 Cable, shielded
3.7 Cable core 3.8 Class II equipment 3.9 Connection box 3.10 DC
Side 3.11 Installation earthing
-
- -
A
A - -
- -
-
A
-
- - -
Part of the PV system from the AC terminals of the inverter
until the grid connection to the mains. A diode that is connected
in parallel with a number of PV cells or the whole PV module.
- - - - -
Part of the PV system from the PV cell to the DC terminals of
the inverter.
-
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
1.4.10 Inverter 1.4.11 ISC MOD 1.4.12 ISC S-ARRAY 1.4.13 ISC
ARRAY 1.4.14 Live Part 1.4.15 PARRAY
- 1.4.16 PV array
3.12 inverter 3.13 ISC STC MOD 3.14 ISC STC-S-ARRAY 3.15 ISC STC
ARRAY 3.16 ISC ARRAY 3.17 PARRAY STC 3.18 PV AC module 3.19 PV
array
- -
A + D
A + D
-
-
A -
-
-
The short circuit current of a PV sub-array at STC, and is equal
to: ISC STC S-ARRAY = ISC STC MOD X SSA NP SA where SSA NP SA is
the number of parallel-connected PV strings in the PV sub-array.
The short circuit current of the PV array at STC, and is equal to:
ISC STC ARRAY = ISC STC MOD x SA NP A where SA NP A is the total
number of parallel-connected PV strings in the PV array.
-
- Combination of a PV module with an integrated DC/AC inverter,
whereas the connection is available on the AC side only. The DC
cannot be accessed.
-
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837:2010
MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
1.4.17 PV array cable 1.4.18 PV array, isolated
3.20 PV array cable 3.21 PV array, isolated
- -
- -
1.4.19 PV array connection box 1.4.20 PV array voltage 1.4.21 PV
cell 1.4.22 PV kWh meter 1.4.23 PV module 1.4.24 PV module
connection box 1.4.25 PV string 1.4.26 PV string cable 1.4.27 PV
sub-array
3.22 PV array connection box 3.23 PV array open circuit voltage
3.24 PV cell 3.25 PV kWh meter 3.26 PV module 3.27 PV module
connection box 3.28 PV string 3.29 PV string cable 3.30 PV
sub-array
-
A + D - - - -
-
-
-
-
The PV array open circuit voltage is considered to be equal to
VOC STC ARRAY (see 1.4.36) (see 3.39). NOTE. The open circuit
voltage is dependent on the cell temperature.
-
-
-
-
-
-
-
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
1.4.28 PV sub-array cable 1.4.29 PV sub-array connection box
1.4.30 PV system 1.4.31 Ripple-free d.c. 1.4.32 SELV (separated
extra-low voltage) 1.4.33 SPD (surge protective device) 1.4.34 STC
(standards test conditions) 1.4.35 VOC MOD 1.4.36 VOC ARRAY
3.31 PV sub-array cable 3.32 PV sub-array connection box 3.33 PV
system 3.34 ripple free DC 3.35 SELV (separated extra-low voltage)
3.36 SPD(surge protective device 3.37 STC (standards test
conditions) 3.38 VOC STC MOD 3.39 VOC STC ARRAY
- -
-
-
-
-
-
-
A + D
-
-
-
-
-
-
-
- The open circuit voltage at STC of a PV array, and is equal
to: VOC STC ARRAY = VOC STC MOD x M Ns where M Ns is the number of
series-connected PV modules in any PV string of the PV array.
Table D1. Changes between MS 1837:2005 and MS 1837:2010 (First
revision) (continued)
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MS 1837:2010
MS 1837 : 2005 Clause No.
MS 1837 : 2010 (First revision)
Clause No.
Additional (A) Or Deletion (D) Amended Text
1.4.37 Voltage
3.40 voltage
A + D
NOTE. This standard assumes that all strings within a PV array
are connected in parallel; hence the open circuit voltage of PV
sub-arrays and PV strings is equal to VOC STC ARRAY. Differences of
potential normally existing between conductors and between
conductors and earth are as follows: a) extra-low voltage (ELV) -
Not exceeding 50 V a.c. AC or 120 V ripple-free d.c. DC; and
b) low voltage (LV) - Exceeding extra-low voltage, but not
exceeding 1 000 V a.c. AC or 1 500 V d.c. DC. NOTE. When
calculating the voltage of a PV array, VOC STC ARRAY is to be
used.
SECTION 2 : GENERAL REQUIREMENTS
4 General Requirements A
The installation of a grid-connected PV system shall be in
accordance with Figure 1 and Figure 2. These figures shall be
extensively referred to throughout this standard.
SECTION 3 : PROTECTION REQUIREMENTS 3.1 General 3.2 By-pass
diodes
5 Protection Requirements 5.1 General 5.2 By-pass diodes
-
A
- By-pass diodes shall be used in the PV modules. If by-pass
diodes are not embedded in the PV module encapsulation, they shall
comply with all the following requirements: a) have a voltage
rating at least 2 x VOC STC MOD of the protected module; b) have a
current rating of at least 1.3 x ISC STC