SIST-TS IEC/TS 62257-9-4:2008

SLOVENSKI STANDARD
SIST-TS IEC/TS 62257-9-4:2008
01-november-2008
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Recommendations for small renewable energy and hybrid systems for rural electrification
- Part 9-4: Integrated system - Userinstallation
Ta slovenski standard je istoveten z: IEC/TS 62257-9-4
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
SIST-TS IEC/TS 62257-9-4:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS IEC/TS 62257-9-4:2008

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SIST-TS IEC/TS 62257-9-4:2008


TECHNICAL IEC


SPECIFICATION TS 62257-9-4





First edition
2006-10


Recommendations for small renewable energy
and hybrid systems for rural electrification –
Part 9-4:
Integrated system –
User installation
© 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.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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International Electrotechnical Commission
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For price, see current catalogue

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SIST-TS IEC/TS 62257-9-4:2008
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CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative reference .6
3 Terms and definitions .6
4 General considerations.7
4.1 General .7
4.2 Installation limits .7
4.3 User interface.7
5 Protection against electric shock .8
5.1 Requirements for d.c. parts of installation.8
5.2 Requirements for a.c. parts of installation.8
6 Protection against overcurrent.9
7 Protection against effect of lightning.10
7.1 Installation supplied from a microgrid .10
7.2 Standalone installation .10
8 Selection and erection of electrical equipment.10
8.1 Wiring system.10
8.2 Isolation and switching .16
8.3 Surge protective devices .17
8.4 Earthing arrangement, protective conductors and protective bonding .17
8.5 User interface.17
9 Verification .17
9.1 Pre-commissioning checks .17
10 Operation and maintenance.18

Annex A (informative) Maximum possible length of circuits with different cables and
conductors to handle maximum voltage drops (ambient temperature 30°C).19

Figure 1 – Installation limits .7
Figure 2 – Protection of persons in an installation supplied from a microgrid according
to a TN-C-S system .8
Figure 3 – Protection of persons in a combined d.c. and a.c. system .9
Figure A.1 – Maximum possible length of circuit as a function of current for a voltage
drop of 3 % in a.c. system in a cable HO5VVF .20
Figure A.2 – Maximum possible length of circuit as a function of current for a voltage
drop of 15 % in d.c. system in a cable 1000RO2V.21

Table 1 – maximum design current of circuits depending on voltages .9
Table 2 – Maximum acceptable voltage drop values in installations .11
Table 3 – Cross-sectional area for copper conductors in fixed installations .11
Table 4 – Selection of wiring systems .12
Table 5 – Installation of wiring systems.13
Table 6 – Fuses/circuit breakers rating and selection for overcurrent protection.17

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SIST-TS IEC/TS 62257-9-4:2008
TS 62257-9-4 © IEC:2006(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-4: Integrated system – User installation


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• The subject is still under technical development or where, for any other reason, there is
the future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62257-9-4, which is a technical specification, has been prepared by IEC technical
committee 82: Solar photovoltaic energy systems.
This part of IEC 62257-9 is based on IEC/PAS 62111 (1999); it cancels and replaces the
relevant parts of IEC/PAS 62111.

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This part of IEC 62257-9 is to be used in conjunction with the IEC 62257 series.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
82/414/DTS 82/441/RVC

Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 62257 series, under the general title Recommendations for small
renewable energy and hybrid systems for rural electrification, can be found on the IEC
website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• transformed into an international standard;
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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TS 62257-9-4 © IEC:2006(E) – 5 –
INTRODUCTION
The IEC 62257 series intends to provide to different players involved in rural electrification
projects (such as project implementers, project contractors, project supervisors, installers,
etc.) documents for the setting up of renewable energy and hybrid systems with a.c. nominal
voltage below 500 V, d.c. nominal voltage below 750 V and nominal power below 100 kVA.
These documents are recommendations:
• to choose the right system for the right place,
• to design the system,
• to operate and maintain the system.
These documents are focused only on rural electrification concentrating on but not specific to
developing countries. They should not be considered as all inclusive to rural electrification.
The documents try to promote the use of Renewable energies in rural electrification; they do
not deal with clean mechanisms developments at this time (CO emission, carbon credit, etc.).
2
Further developments in this field could be introduced in future steps.
This consistent set of documents is best considered as a whole with different parts
corresponding to items for safety, sustainability of systems and at the lowest life cycle cost as
possible. One of the main objectives is to provide the minimum sufficient requirements,
relevant to the field of application that is: small renewable energy and hybrid off-grid systems.

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SIST-TS IEC/TS 62257-9-4:2008
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RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-4: Integrated system – User installation



1 Scope
The purpose of this part of IEC 62257 is to specify the general requirements for the design
and the implementation of a user's installation.
This part of IEC 62257-9 applies to single phase user's electrical installations with maximum
power of 500 VA, in Decentralized Rural Electrification Systems (DRES).
NOTE For installations above 500 VA in decentralized electrification systems, IEC 62257-5 applies.
This part of IEC 62257-9 is applicable to installations supplied by a microgrid (120 V a.c. or
230 V a.c.) and to installations encompassing their own single-unit micropowerplant (120 V
a.c. or 230 V a.c. or 12 V d.c. or 24 V d.c.)
The part of IEC 62257-9 applies neither to the electric power production and distribution
installations described in the sections concerning microplants and microgrids, nor to user
electrical equipment. It details the rules governing the design and construction of consumer’s
electrical installations for the purpose of ensuring the safety of persons and property, and
satisfactory operation in accordance with the purpose for which the installations are designed.
It applies to new installations and modifications of existing installations.
2 Normative reference
The following referenced documents are essential for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60269 (all parts), Low-voltage fuses
IEC 60364-5-52, Electrical installations of buildings – Part 5-52: Selection and erection of
electrical equipment – Wiring systems
IEC 62257 (all parts), Recommendations for small renewable energy and hybrid systems for
rural electrification
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
protective conductor
(identification: PE)
conductor provided for purposes of safety, for example protection against electric shock
NOTE In an electrical installation, the conductor identified PE is normally also considered as protective earthing
conductor.
[IEV 195-02-09]

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TS 62257-9-4 © IEC:2006(E) – 7 –
3.2
PEN conductor
conductor combining the functions of a protective earthing conductor and a neutral conductor
[IEV 195-02-12]
3.3
equipotential bonding
provision of electric connections between conductive parts, intended to achieve
equipotentiality
NOTE The role of the equipotential bonding is to decrease the difference in potential that can exists between two
exposed-conductive parts of an installation.
3.4
surge arrester
device designed to protect the electrical apparatus from high transient overvoltages and to
limit the duration and frequently, the amplitude of the follow-on current
3.5
supply point
contractual limit between the grid and the user’s installation
NOTE In rural electrification systems, it is generally located on the input terminals (microgrid side) of the user’s
interface.
3.6
Surge Protective Device
SPD
device that is intended to protect the electrical apparatus from transient overvoltages and
divert surge current; it contains at least one non linear component
4 General considerations
4.1 General
User installations shall be designed to ensure protection of persons, animal and equipment in
compliance with IEC 62257- 5.
Specific requirements for generators associated with stand-alone user installations are
provided in the relevant part of the IEC 62257-7 series.
4.2 Installation limits
Installation limits are illustrated in following Figure 1.
Production Distribution User

sub-system sub-system sub-system
Microgrid Installation
Micropowerplant
Other
User interface
Generator
equipment
IEC  1909/06

Figure 1 – Installation limits
4.3 User interface
See IEC 62257-9-3.

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5 Protection against electric shock
5.1 Requirements for d.c. parts of installation
Simple separation, at least, shall be provided between the d.c. side and the a.c. side of a
stand-alone installation (for a PV array, see also IEC 62257-7-1).
5.2 Requirements for a.c. parts of installation
5.2.1 General
The characteristics of the protective devices shall be such that if a fault of negligible
impedance occurs anywhere in the installation between a phase conductor and a protective
conductor or exposed conductive part, automatic disconnection of the supply will occur within
0,4 s.
A residual current protective device, with a rated operating residual current not exceeding
30 mA shall be provided as additional protection for each installation. It shall be placed in the
user's interface housing.
5.2.2 Neutral earthing system
5.2.2.1 Installation supplied from a microgrid or standalone installation
encompassing a micropowerplant 230 V or 120 V a.c.
User’s electrical installation should be preferably designed according to a TN-S system.
NOTE 1 The TT system is not recommended for the user’s installation, because for the TT system, each house is
equipped with an earth electrode. For the electrification of remote villages, it could be difficult to install and
maintain an effective earth electrode in each house.
Figure 2 illustrates the fault current circulation in TN-C-S systems.
NOTE 2 The “grey box” called “user interface” is specified in IEC 62257-9-3.

User interface
Ph Ph
Microgrid
User
PEN
N
a.c. source
PE
loads
Fault current circulation IEC  1946/06

Figure 2 – Protection of persons in an installation supplied
from a microgrid according to a TN-C-S system

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TS 62257-9-4 © IEC:2006(E) – 9 –
5.2.2.2 Standalone installation with a.c. and d.c. electrical circuits, encompassing
d.c. micropowerplant (ex: PV generators)
IEC 62257-5 provides provisions to apply on d.c. and a.c. circuits.
For combined systems in which a part of the installation is 12 V / 24 V d.c. and the other part
is 120 V or 230 V a.c., through a d.c./a.c. converter, a TN-S system shall be created for the
a.c. part. The PE conductor shall be earthed.
Figure 3 shows the fault current circulation and the principles for protection of persons in a
combined d.c. and a.c. system.


User interface
User
d.c.
loads
Micro
Ph
powerplant
d.c. and a.c.
User
N
a.c.
PE
loads
Fault current circulation
IEC  1947/06


Figure 3 – Protection of persons in a combined d.c. and a.c. system
6 Protection against overcurrent
The installation may consist of one single circuit or be divided in several sub-circuits. Each
circuit shall be protected against overcurrent. Where the installation comprises only one
circuit, the overcurrent protective device is located in the user's interface housing.
NOTE 1 if the sub-circuits have the same cross sectional area as the ma
...