IEC TS 62257-7-1:2006

Recommendations for small renewable energy and hybrid systems for rural electrification - Part 7-1: Generators - Photovoltaic arrays

Specifies the general requirements for erection and operation of PV arrays in decentralized rural electrification systems. Provides safety and fire protection requirements for ELV and LV PV arrays intended to uninformed persons, including owners and users of the premises where photovoltaic arrays are installed; informed workers (e.g. electricians) working on these systems; and emergency workers (for example fire fighters).

General Information

• Status: Published
• Publication Date: 13-Dec-2006
• ICS: 27.160 - Solar energy engineering
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 29-Sep-2010

Relations

• Revised: IEC TS 62257-7-1:2010 - Recommendations for small renewable energy and hybrid systems for rural electrification - Part 7-1: Generators - Photovoltaic generators
• Effective Date: 05-Sep-2023

Standards Content (Sample)

TECHNICAL IEC
SPECIFICATION TS 62257-7-1
First edition
2006-12
Recommendations for small renewable energy
and hybrid systems for rural electrification –
Part 7-1:
Generators – Photovoltaic arrays

Reference number
IEC/TS 62257-7-1:2006(E)
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TECHNICAL IEC
SPECIFICATION TS 62257-7-1
First edition
2006-12
Recommendations for small renewable energy
and hybrid systems for rural electrification –
Part 7-1:
Generators – Photovoltaic arrays

© IEC 2006 ⎯ Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
XC
Commission Electrotechnique Internationale

International Electrotechnical Commission
For price, see current catalogue
МеждународнаяЭлектротехническаяКомиссия

– 2 – TS 62257-7-1© IEC:2006(E)

CONTENTS
FOREWORD.4

INTRODUCTION.6

1 Scope.7

2 Normative references .8

3 Terms and definitions .9

4 Design.15
4.1 Electrical design.15
4.2 Mechanical design.27
5 Safety issues.28
5.1 General .28
5.2 Protection against electric shock and fire .28
5.3 Protection against overcurrent.28
5.4 Protection against effects of lightning and over-voltage .31
6 Selection and erection of electrical equipment.32
6.1 Component requirements .32
6.2 Location and installation requirements .36
7 Acceptance .43
7.1 General .43
7.2 Conformance with system general specification.43
7.3 Wiring and installation integrity.43
7.4 Open circuit voltage .43
7.5 Open circuit voltage measurements for large PV arrays .44
7.6 Short circuit current measurements .45
7.7 Commissioning records .46
8 Operation/maintenance .47
8.1 General .47
8.2 Safety .47
8.3 Operation and maintenance procedures .47
9 Replacement .47
10 Marking and documentation.48

10.1 Equipment marking.48
10.2 Requirements for signs.48
10.3 Labelling of PV array and PV sub-array junction boxes.48
10.4 Labelling of disconnection devices .48
10.5 Fire emergency information signs.48
10.6 Documentation .49

Annex A (informative) Examples of commissioning records.50
Annex B (informative) Example of maintenance schedule .53
Annex C (informative) Replacement.55
Annex D (informative) Examples of signs.56
Annex E (informative) Case studies .57
Annex F (informative) Double switching in PV array.72

TS 62257-7-1© IEC:2006(E) – 3 –

Figure 1 – General functional configuration of a PV powered system .15

Figure 2a – Unearthed PV array and unearthed d.c. load application circuit.17

Figure 2b – Unearthed PV array and earthed d.c. load application circuit.17

Figure 2c – Unearthed PV array connected to a.c. loads via an isolated PCU

application circuit.18

Figure 2d – Unearthed PV array connected to a.c. loads via a non-isolated PCU

application circuit.18

Figure 2e – Earthed PV array and unearthed d.c. load application circuit.18

Figure 2f – Earthed PV array and earthed d.c. load application circuit.19
Figure 2g – Earthed PV array connected to a.c. loads via an isolated PCU application
circuit.19
Figure 2h – Centre-tapped earthed PV array connected to a.c. loads via an isolated
PCU application circuit.19
Figure 2i – Earthed PV array connected to a.c. loads via a non-isolated PCU
application circuit.19
Figure 2 – PV system earthing configurations .19
Figure 3 – PV array exposed-conductive parts earthing decision tree .20
Figure 4 – Unearthed PV array and d.c. loads configuration.21
Figure 5 – PV array diagram – single string case .22
Figure 6 – PV array diagram – multi-string case.23
Figure 7 – PV array diagram – multi-string case with array divided into sub-arrays .24
Figure 8 – Blocking diode implementation (example) .36
Figure 9 – PV string wiring with minimum loop area .41
Figure D.1 – Example of sign required on PV array junction box (10.3) .56
Figure D.2 – Example of sign required adjacent to PV array main switch (10.4.2.) .56
Figure D.3 – Example of fire emergency information sign required in main building
switchboard (10.5.1) .56
Figure F.1 – Floating PV array operating at maximum power point.73
Figure F.2 – Floating PV array with single earth fault .74
Figure F.3 – Floating PV array with double earth fault.75
Figure F.4 – Floating PV array with double earth fault.76

Table 1 – Voltage domains for PV arrays .7
Table 2 – PV system earthing configurations .16
Table 3 – Number of parallel strings without overcurrent protection, n .29
P
Table 4 – Requirements for location of overcurrent protective devices according to the
earth configuration.30
Table 5 – Current rating of PV array circuits .34
Table 6 – Disconnecting means requirements in PV array installations .37
Table 7 – Location of disconnection devices according to system configuration, where
required .37
Table E.1 – Case studies overview list.57

– 4 – TS 62257-7-1© IEC:2006(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY AND

HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 7-1: Generators – Photovoltaic arrays

FOREWORD
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