Electrical Insulation in Power Systems

409 Pages·1998·12.705 MB·\409

by  Malik (Author)

Electrical Insulation
in Power Systems
POWER ENGINEERING
Series Editor
H. Lee Willis
ABB Power T&D Company Inc.
Cary, North Carolina
1. Power Distribution Planning Reference Book, H. Lee WUHs
2. Transmission Network Protection: Theory and Practice, K G.
Paithankar
3. Electrical Insulation in Power Systems, N. H. Malik, A. A. Al-Arainy,
and M. L Qureshi
4. Electrical Power Equipment Maintenance and Testing, Paul Gill
5. Protective Relaying: Principles and Applications, Second Edition, J.
Lewis Blackburn
ADDITIONAL VOLUMES IN PREPARATION
Electrical Insulation
in Power Systems
N. H. Malik
A. A. Al-Arainy
M. I. Qureshi
King Sand University
Riyadh, Saudi Arabia
Taylor &. Francis
Taylor Francis Group
Boca Raton London New York Singapore
A CRC title, part of the Taylor Sr Francis imprint, a member of the
Taylor Sr Francis Group, the academic division of TSrF Informa pic.
Library of Congress Cataloging-in-Publication Data
Electrical insulation in power systems / by Nazar Hussain Malik, A. A. Al-Arainy,
Mohammad Iqbal Qureshi.
p. cm. - (Power engineering ; 3)
Includes bibliographical references and index.
ISBN 0-8247-0106-2 (hardcover)
1. Electric insulators and insulation. 2. Electric power systems—Protection.
3. Dielectrics. I. Malik, Nazar Hussain . II. Al-Arainy, A. A. III. Qureshi,
Mohammad Iqbal. IV. Series
TK3401.E42 1997
621.319'37-dc21 97-34427
CIP
The publisher offers discounts on this book when ordered in bulk quantities. For
more information, write to Special Sales/Professional Marketing at the address
below.
This book is printed on acid-free paper.
Copyright © 1998 by MARCEL DEKKER All Rights Reserved.
Neither this book nor any part may be reproduced or transmitted in any form or
by any means, electronic or mechanical, including photocopying, microfilming,
and recording, or by any information storage and retrieval system, without
permission in writing from the publisher.
MARCEL DEKKER
270 Madison Avenue, New York, New York 10016
http://WWW. dekker. com
Current printing (last digit):
10 9 8 7 6 5 4 3 2
PRINTED IN THE UNITED STATES OF AMERICA
Series Introduction
Power engineering is the oldest and most traditional of the various areas within
electrical engineering, yet no other facet of modem technology is currently
undergoing a more dramatic revolution in both technology and industry
stmcture. As these changes take place, many of the traditional and fundamental
areas of power engineering become more important than ever. Certainly one
such area is insulation. Always an essential element for satisfactory power
system operation, its correct interpretation and application becomes more
critical at a time when deregulated power grids are utilizing ever higher voltage
levels to move greater amounts of power over longer distances.
Electrical Insulation in Power Systems, by Drs. Malik, Al-Arainy, and
Qureshi, is a particularly useful book, because it combines a very
comprehensive coverage of insulation methods with a consistent attention to
detail and practical application. All of the insulation approaches used in modem
power systems are presented in a straightforward and thorough manner,
including vacuum, air, gas, liquid, solid and composite dielectric technologies.
Within each ^rea, the authors address the traditional fundamentals completely,
and provide a good discussion of recent developments and their applications.
Equally important are the final three chapters of the book, which provide a very
cogent and well-organized presentation on testing and diagnostic procedures and
the interpretation of their results.
As the editor of the Power Engineering Series, I am proud to include
Electrical Insulation in Power Systems among this important group of books.
Like all the books in this series, this volume presents modem power technology
in a context of proven and practical application. It is useful as a reference book,
as a text in an advanced power systems curriculum, or for self-study and tutorial
III
iv Series Introduction
application. The Power Engineering series will eventually include books
covering the entire field of power engineering, in all of its specialties and
subgenres, all aimed at providing practicing power engineers with the
knowledge and techniques they need to meet the challenges of the electric
industry in the 21st century.
H. Lee Willis
Preface
Electrical insulation is the backbone of all modern power system networks.
Different types of dielectrics that constitute these insulating elements are
subjected to a variety of stresses during their life span. A thorough knowl­
edge of their fundamental properties is therefore essential for their appro­
priate and optimal design as well as their pre- and postinstallation testing
and reliable operation.
The rapidly growing demand for electrical energy in the world today
necessitates its transmission at extra high voltage levels. Electrical power
engineers must efficiently tackle the complicated problems of insulation
and overvoltages arising in power networks. To train and better equip these
engineers now and for the future, it is necessary that they be provided with
a relevant specialized background. At present, only a few books are avail­
able that address this problem, particularly when compared with the num­
ber of those published in other areas of electrical engineering. Even among
these few, no single book covers the entire range of essential topics. Some
are almost two decades old, and others are limited to monographs on spe­
cific individual topics such as switchgear, corona, insulating oils and gas
insulated systems (GIS). There is therefore a great need for a book that
covers in a single volume the topics that are pertinent to the electrical
engineer working with high voltage insulation.
Electrical Insulation in Power Systems is an attempt to fill this gap. It
is expected to be of considerable importance not only for engineers in­
volved with power utilities and the insulation industry, but also for senior
undergraduate and postgraduate students. We are associated with the sub­
VI Preface
ject of high voltage insulation as researchers and as teachers, at both the
undergraduate and graduate levels, of specially tailored courses for prac­
ticing engineers working in industry and electric utilities. Most of the ma­
terial presented in this book is the outcome of lectures prepared for uni­
versity and industry audiences. The book covers in detail the fundamental
properties of dielectrics and their desirable properties for pertinent power
applications as well as the means of assessing the performance of materials
and equipment in the laboratory and in service. This book will certainly
enable the reader to understand high voltage insulation better and apply
that knowledge more effectively.
This book comprises 12 chapters. Each chapter deals with a specific
aspect of the subject and can be read as a self-contained unit with inclusive
references. In Chapter 1, the reader is introduced to the importance and
development of high voltage insulation technology through a brief descrip­
tion of important individual elements of modern power system networks
together with a general perspective of the important properties of insulating
materials. Chapter 2 is devoted to basic gas discharge mechanisms; Chapter
3 describes the air clearances necessary for transmission network and sub­
station equipment, plus the factors that conspicuously control these clear­
ances. No networks exist that do not employ sections of SF^ CIS. Chapter
4 describes the fundamental mechanisms that control breakdown in SF^
gas and offers a detailed account of SF^ circuit breakers and CIS techniques
generally encountered in modern power networks. Chapters 5 and 6 de­
scribe the importance and classification of liquid and solid dielectrics. We
deal with their electrical properties in detail and then cover their conduction
and breakdown aspects. Vacuum as a dielectric is described in Chapter 7,
whereas Chapter 8 is concerned with composite insulation. Polymeric and
oil-filled cables are an integral part of a power network, so Chapter 9 has
been devoted solely to the treatment of this topic. Chapter 10 contains a
iiscussion of the methods for generation and measurement of high test
oltages.
With the advent of digital/opto electronics and microprocessors, most
of the measurement techniques in almost every branch of technology have
been modified. This applies to the high voltage measurements and diag­
nostic techniques as well. In the past decade, a variety of such techniques
have been introduced and today many power stations are equipped with
this equipment. Until now, details of such methods were available only in
scattered form in the literature. Chapter 11 is fully devoted to a detailed
survey of these techniques.
It is very important, for design engineers as well as practicing engi­
neers, to test the ability of an insulation system or apparatus to meet the
guaranteed specifications. For this purpose, testing prior to and after in­
Preface vii
stallation is generally necessary. Chapter 12 deals with high voltage testing
techniques, including their internationally accepted classifications, test pro­
cedures and standards. Newcomers to this field as well as experienced
designers of equipment and practicing engineers will find this vital infor­
mation presented in a systematic way to make them aware of the latest
techniques in their chosen field.
We welcome constructive suggestions for future editions of this book.
N. H. Malik
A. A. Al-Arainy
M. /. Qureshi