IEC_TS_62257-9-2-2006.pdf

TECHNICAL SPECIFICATION IECTS 62257-9-2 First edition2006-10 Recommendations for small renewable energy and hybrid systems for rural electrification Part 9-2:Microgrids Reference number IEC/TS 62257-9-2:2006(E)LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.Publication numbering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series.For example,IEC 34-1 is now referred to as IEC 60034-1.Consolidated editions The IEC is now publishing consolidated versions of its publications.For example,edition numbers 1.0,1.1 and 1.2 refer,respectively,to the base publication,the base publication incorporating amendment 1 and the base publication incorporating amendments 1 and 2.Further information on IEC publications The technical content of IEC publications is kept under constant review by the IEC,thus ensuring that the content reflects current technology.Information relating to this publication,including its validity,is available in the IEC Catalogue of publications(see below)in addition to new editions,amendments and corrigenda.Information on the subjects under consideration and work in progress undertaken by the technical committee which has prepared this publication,as well as the list of publications issued,is also available from the following:IEC Web Site(www.iec.ch)Catalogue of IEC publications The on-line catalogue on the IEC web site(www.iec.ch/searchpub)enables you to search by a variety of criteria including text searches,technical committees and date of publication.On-line information is also available on recently issued publications,withdrawn and replaced publications,as well as corrigenda.IEC Just Published This summary of recently issued publications(www.iec.ch/online_news/justpub)is also available by email.Please contact the Customer Service Centre(see below)for further information.Customer Service Centre If you have any questions regarding this publication or need further assistance,please contact the Customer Service Centre:Email:custserviec.ch Tel:+41 22 919 02 11 Fax:+41 22 919 03 00 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.TECHNICAL SPECIFICATION IECTS 62257-9-2 First edition2006-10 Recommendations for small renewable energy and hybrid systems for rural electrification Part 9-2:Microgrids PRICE CODE 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 Varemb,PO Box 131,CH-1211 Geneva 20,SwitzerlandTelephone:+41 22 919 02 11 Telefax:+41 22 919 03 00 E-mail:inmailiec.ch Web:www.iec.ch XA For price,see current catalogueCommission Electrotechnique InternationaleInternational Electrotechnical Commission LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.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 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.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(o