IEC TS 62257-9-2:2006

Recommendations for small renewable energy and hybrid systems for rural electrification - Part 9-2: Microgrids

Specifies the general requirements for the design and the implementation of microgrids used in decentralized rural electrification to ensure the safety of persons and property and their satisfactory operation according to the scheduled use.

General Information

• Status: Published
• Publication Date: 08-Oct-2006
• ICS: 27.160 - Solar energy engineering
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: JWG 1 - TC 82/JWG 1
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 27-Sep-2016

Relations

• Revised: IEC TS 62257-9-2:2016 - Recommendations for renewable energy and hybrid systems for rural electrification - Part 9-2: Integrated systems - Microgrids
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC/TS 62257-9-2 ®
Edition 1.0 2006-10
TECHNICAL
SPECIFICATION
colour
inside
Recommendations for small renewable energy and hybrid systems for rural
electrification –
Part 9-2: Microgrids
IEC/TS 62257-9-2:2006(E)
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IEC/TS 62257-9-2 ®
Edition 1.0 2006-10
TECHNICAL
SPECIFICATION
colour
inside
Recommendations for small renewable energy and hybrid systems for rural
electrification –
Part 9-2: Microgrids
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XA
ICS 27.160; 27.180 ISBN 2-8318-8863-8

– 2 – TS 62257-9-2 © IEC:2006(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative reference .7
3 Terms and definitions .7
4 General .9
4.1 Limits of a microgrid .9
4.2 Voltage drops.9
4.3 Composition of a microgrid.9
5 Protection against electric shocks.11
6 Protection against overcurrents .11
7 Selection and erection of equipment.11
7.1 Equipment installation .11
7.2 Operational conditions and external influences.11
7.3 Characteristics of lines .13
7.4 Cables.14
7.5 Poles.14
7.6 Cable anchorage .17
7.7 Connections and accessories .17
7.8 Where poles are used for other purposes .19
7.9 Isolation and switching .19
7.10 Earthing arrangement, protective conductors and protective bonding
conductors .20
8 Verification and acceptance.22
8.1 General .22
8.2 Supervision of works .22
8.3 Verification before commissioning (on site acceptance).22
8.4 Operation tests.23

Annex A (informative) Characteristics of cables .24
Annex B (informative) Maximum circuit length.26

Figure 1 – Microgrid limits.9
Figure 2 – Microgrid consisting of a single-phase feeder.10
Figure 3 – Three phase system output, single phase distribution or three phase
service provided where needed.10
Figure 4 – Three phase system output, single phase distribution .11
Figure 5 – Diagram showing installation of twinned wooden poles forming an angle .16
Figure 6 – Examples of different pole arrangements .16
Figure 7 – Example of an overhead line .16
Figure 8 – Connection mode diagram.19
Figure 9 – Microgrid earthing scheme .21

TS 62257-9-2 © IEC:2006(E) – 3 –

Table 1 – Maximum values of voltage drops.9
Table 2 – Fuse ratings for protection from short-circuiting in 230 V a.c. microgrids
(overhead lines).20
Table 3 – Fuse ratings for protection from short-circuiting in 120 V a.c. microgrids
(overhead lines).20
Table 4 – Circuit breaker ratings for protection from short-circuiting in microgrids
(overhead lines).20
Table 5 – Characteristics of earthing components.22
Table A.1 – Example of characteristics of grid conductors for overhead lines (insulated
twisted conductors without carrier neutral) .24

– 4 – TS 62257-9-2 © IEC:2006(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION

Part 9-2: Microgrids
FOREWORD
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• the required support cannot be obtained for the publication of an International Standard,
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• 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 62257-9-2, 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.

TS 62257-9-2 © IEC:2006(E) – 5 –
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
82/412/DTS 82/443/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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