IEC_PAS_62344-2007.pdf

PUBLICLY AVAILABLE SPECIFICATION IEC PAS 62344Pre-Standard First edition2007-05 General guidelines for the design of ground electrodes for high-voltage direct current(HVDC)links Reference number IEC/PAS 62344:2007(E)LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2007 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,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 either IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.IEC Central Office 3,rue de Varemb CH-1211 Geneva 20 Switzerland Email:inmailiec.ch Web:www.iec.ch About the IEC The International Electrotechnical Commission(IEC)is the leading global organization that prepares and publishes International Standards for all electrical,electronic and related technologies.About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigenda or an amendment might have been published.?Catalogue of IEC publications:www.iec.ch/searchpub The IEC on-line Catalogue enables you to search by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,withdrawn and replaced publications.?IEC Just Published:www.iec.ch/online_news/justpub Stay up to date on all new IEC publications.Just Published details twice a month all new publications released.Available on-line and also by email.?Customer Service Centre:www.iec.ch/webstore/custserv If you wish to give us your feedback on this publication or need further assistance,please visit the Customer Service Centre FAQ or contact us:Email:csciec.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.PUBLICLY AVAILABLE SPECIFICATIONIEC PAS 62344Pre-Standard First edition2007-05 General guidelines for the design of ground electrodes for high-voltage direct current(HVDC)links PRICE CODE X 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 PAS 62344 IEC:2007(E)CONTENTS FOREWORD.4 INTRODUCTION.5 1 Scope.6 2 Basic concepts.6 2.1 Monopolar system.6 2.2 Bipolar system.7 2.3 Mixed or combined systems.8 3 Electric field as the decisive factor for selection of site.9 3.1 Why is the electric field the decisive factor?.9 3.2 Data necessary to determine the field.9 3.2.1 Reference currents(or electrode rating).9 3.2.2 Resistivity data.9 3.3 Considerations on site selection.9 3.4 Calculation of field.10 3.5 Apparent resistivity.11 4 Impact of the field on buried metallic objects.11 4.1 Impact on non-insulated buried metallic objects.11 4.2 Impact on insulated metallic objects.12 4.3 Impact on an a.c.grid.12 4.4 Reduction of impact due to polarization.14 4.4.1 Polarization on non-insulated metallic objects.14 4.4.2 Polarization on insulated metallic objects.16 4.4.3 Reduction of star-point currents due to polarization.16 5 Compass errors.17 6 Types of electrode stations.17 7 Design aspects for land electrodes.18 7.1 General.18 7.2 Heating of soil.19 7.3 Moisture content of soil/electric osmosis.20 7.4 Material for land electrodes.20 7.4.1 Inner conductor.20 7.4.2 Coke or graphite powder filling.21 7.5 Geometric layout of the electrode.22 7.5.1 Horizontal arrangements.22 7.5.2 Vertical arrangements.24 7.6 Step voltage.24 7.7 Touch voltage.25 8 Design aspects for sea electrodes.25 8.1 General.25 8.2 Sea electrodes using titanium as active part(anodic operation).26 8.2.1 Material.26 8.2.2 Current density and gradients.26 8.2.3 Geometric layout.26 8.3 Sea electrodes using coke or SiFeCr-rods as active parts(reversible operation).27 8.3.1 Overheating risk.27 8.3.2 Material for sea electrodes.27 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.PAS 62344 IEC:2007(E)3 8.3.3 Geometric layout of reversible sea electrodes.28 8.4 Sea electrodes using bare copper conductors as active parts(cathodic operation only).28 9 Design aspects for shore electrodes.30 9.1 General.30 9.2 Beach electrode stations.30 9.3 Pond electrode stations.32 10 Chemical aspects.34 11 Connection converter station Electrode station.35 11.1 Separation of a.c.grid from electrode station.35 11.2 Constructional principles of electrode connection.36 11.3 Detection of faults on electrode connections.36 11.4