IEC/TS 62257-9-3

Recommendations for small renewable energy and hybrid systems for rural electrification - Part 9-3: Integrated system - User interface

Specifies the general requirements for the design and the implementation of the interface equipment within the user's installation which connects to a microgrid or the generating part of a standalone system.

Priporočila za sisteme malih obnovljivih virov energije in hibridne sisteme za elektrifikacijo podeželja - 9-3. del: integrirani sistem - Uporabniški vmesnik

General Information

• Status: Not Published
• ICS: 27.160 - Solar energy engineering
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Current Stage: PPUB - Publication issued
• Start Date: 09-Oct-2006
• Ref Project: SIST-TS IEC/TS 62257-9-3:2008 - Recommendations for small renewable energy and hybrid systems for rural electrification - Part 9-3: Integrated system - User interface

Overview

IEC/TS 62257-9-3 - "Recommendations for small renewable energy and hybrid systems for rural electrification - Part 9-3: Integrated system - User interface" specifies general requirements for the design and implementation of the user-side interface equipment that connects a household or small installation to a microgrid or the generating part of a standalone system. The technical specification focuses on simplified user interfaces (distribution boards) used in decentralized rural electrification systems (DRES) with maximum user power of 500 VA.

Key topics and technical requirements

• Scope and applicability
  • Applies to user interfaces that connect to 230 V or 120 V AC microgrids, AC or DC generators, and low-voltage PV systems (e.g., 12 V, 24 V DC).
  • Focused on small renewable energy and hybrid systems for rural electrification.
• Core functions (from Table 1)
  • A Connection to electricity sources (microgrid or generator)
  • B Isolation from electricity sources
  • C Protection against electric shock
  • D / D1 Protection against overloads and short-circuits
  • E Contract management (where relevant)
  • F Earthing terminal
  • G Distribution of circuits
• Equipment and construction
  • User interface should be a type-tested assembly complying with IEC 60439-3 (distribution boards for use by unskilled persons) or assembled per manufacturer’s instructions.
  • Design and erection topics covered include system earthing (TN‑S selected for this part), insulation requirements, selection of electrical equipment, housing, and protection against fraudulent use.
• Verification and commissioning
  • The specification includes requirements for marking, information to be provided to users, inspection, verification and commissioning tests to ensure safe operation.
• Terminology and protective devices
  • Definitions include surge arresters and Surge Protective Devices (SPDs), protective conductors (PE) and PEN conductors.

Practical applications

• Design and specification of user-side distribution boards for rural microgrids and standalone PV/battery systems.
• Site installation and commissioning checklists for rural electrification installers and system integrators.
• Safety and protection guidance for low-power household interfaces in off‑grid and mini‑grid projects.
• Basis for procurement, type‑testing and marking of user interface assemblies for decentralized renewable systems.

Who should use this standard

• Rural electrification project implementers and contractors
• Microgrid designers and system integrators
• Distribution board and enclosure manufacturers targeting off‑grid markets
• Installers, commissioning engineers and project supervisors
• Policymakers and funders specifying minimum safety and interface requirements

Related standards

• IEC 62257 series (overall recommendations for small renewable and hybrid systems)
• IEC 60439-3 (low-voltage distribution boards)
• IEC 60364 (electrical installations of buildings)

Keywords: IEC 62257-9-3, microgrid user interface, rural electrification, distribution board, standalone PV, TN‑S earthing, protection and isolation, small renewable energy systems.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2008
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HOHNWULILNDFLMRSRGHåHOMDGHOLQWHJULUDQLVLVWHP8SRUDEQLãNLYPHVQLN
Recommendations for small renewable energy and hybrid systems for rural electrification
- Part 9-3: Integrated system - User interface
Ta slovenski standard je istoveten z: IEC/TS 62257-9-3
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL IEC
SPECIFICATION TS 62257-9-3
First edition
2006-10
Recommendations for small renewable energy
and hybrid systems for rural electrification –
Part 9-3:
Integrated system –
User interface
© 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
Commission Electrotechnique Internationale M

International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – TS 62257-9-3 © IEC:2006(E)

CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative reference .6
3 Terms and definitions .7
4 Electrical characteristics.9
4.1 Equipment.9
4.2 System voltages .9
5 Functional description .9
6 Design and erection .10
6.1 System earthing .10
6.2 Implementation of interface functions .10
6.3 Insulation requirements .11
6.4 Selection of electrical equipment .11
6.5 Housing.11
6.6 Protection against fraudulent use .12
7 Information to be given and marking.12
8 Verification and acceptance.12
8.1 General .12
8.2 Verification by inspection.12
8.3 Commissioning tests .13

Figure 1 – General configuration of an electrification system .6
Figure 2 – Interface for user installations supplied from a a.c. or a d.c. source .9
Figure 3 – Interface for user installations supplied locally from a.c. or d.c. sources (not
from a microgrid) .10

Table 1 – Functions ensured by various types of user interfaces.9

TS 62257-9-3 © IEC:2006(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-3: Integrated system – User interface

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 62257-9-3, 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.

– 4 – TS 62257-9-3 © IEC:2006(E)

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
82/413/DTS 82/440/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.

TS 62257-9-3 © 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.).
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.

– 6 – TS 62257-9-3 © IEC:2006(E)

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

Part 9-3: Integrated system – User interface

1 Scope
The purpose of this part of IEC 62257 is to specify the general requirements for the design
and the implementation of the interface equipment within the user’s installation which
connects to a microgrid or the generating part of a standalone system.
This interface is a part of the user’s installation as shown in Figure 1.

Production Distribution
User
sub-system sub-system
sub-system
Microgrid Installation
Micropowerplant
Other
User interface
Generator
equipment
IEC  1909/06
Figure 1 – General configuration of an electrification system
This part of IEC 62257-9 applies to a simplified user's interfaces (distribution board) in
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 applies to an interface equipment within the user’s installation and
which connects the user's installation to:
• 230 V a.c. or 120 V a.c. microgrid,
• the generating part – a.c. or d.
...