MALAYSIAN MS 1837:2010portal.unimap.edu.my/portal/page/portal30/Lecture... · This Malaysian...

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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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,

standardisation and accreditation as a means of advancing the national economy,

promoting industrial efficiency and development, benefiting the health and safety of

the public, protecting the consumers, facilitating domestic and 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 develop, distribute and sell the Malaysian Standards.

For further information on Malaysian Standards, please contact:

Department of Standards Malaysia OR SIRIM Berhad Ministry of Science, Technology and Innovation (Company No. 367474 - V) Level 1 & 2, Block 2300, Century Square 1, Persiaran Dato’ Menteri Jalan Usahawan Section 2 63000 Cyberjaya 40000 Shah Alam Selangor Darul Ehsan Selangor Darul Ehsan MALAYSIA MALAYSIA Tel: 60 3 8318 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]

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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)

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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).

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

© S

TAN

DA

RD

S MA

LAYSIA 2010 – A

ll rights reserved

9

MS 1837:2010

Figure 1. Schematic diagram of a grid-connected PV system (single-phase)

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

10 ©

STA

ND

AR

DS

MA

LAYSIA 2010 – A

ll rights reserved

MS 1837:2010

Figure 2. Schematic diagram of a grid-connected PV system (three-phase)

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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).

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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;

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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).

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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).

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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:

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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).

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

MS 1837:2010


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.

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

1

© STA

ND

ARD

S M

ALAYSIA

2010 - All rights reserved

31

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”;

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

32

MS 1837:2010

32

©

STAN

DAR

DS

MALAY

SIA 2010 - A

ll rights reserved



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)

Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

1

© STA

ND

ARD

S M

ALAYSIA


33

MS 1837:2010



Clause No.


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


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

34

MS 1837:2010

34

©

STAN

DAR

DS

MALAY

SIA 2010 - A

ll rights reserved



Clause No.


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


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

1

© STA

ND

ARD

S M

ALAYSIA


35

MS 1837:2010



Clause No.


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.

-


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

36

MS 1837:2010

36

©

STAN

DAR

DS

MALAY

SIA 2010 - A

ll rights reserved



Clause No.


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.

-


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

1

© STA

ND

ARD

S M

ALAYSIA


37

MS 1837:2010



Clause No.


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.

-

-

-

-

-

-

-


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

38

MS 1837:2010

38

©

STAN

DAR

DS

MALAY

SIA 2010 - A

ll rights reserved



Clause No.


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.


Lice

nsed

to U

NIV

ER

SIT

I MA

LAY

SIA

PE

RLI

S (

UN

IMA

P)

/ Dow

nloa

ded

on :

21-F

eb-2

014

12:3

4:02

PM

/ S

ingl

e us

er li

cens

e on

ly, c

opyi

ng a

nd n

etw

orki

ng p

rohi

bite

d

1

© STA

ND

ARD

S M

ALAYSIA


39

MS 1837:2010



Clause No.


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

MALAYSIAN MS 1837:2010portal.unimap.edu.my/portal/page/portal30/Lecture... · This Malaysian...

Documents

Transcript of MALAYSIAN MS 1837:2010portal.unimap.edu.my/portal/page/portal30/Lecture... · This Malaysian...