高电压技术.pdf

THIS PAGE ISBLANKCopyright 2007,New Age International(P)Ltd.,PublishersPublished by New Age International(P)Ltd.,PublishersAll rights reserved.No part of this ebook may be reproduced in any form,by photostat,microfilm,xerography,or any other means,or incorporated into any information retrievalsystem,electronic or mechanical,without the written permission of thepublisher.All inquiries should be emailed to ISBN(10):81-224-2323-XISBN(13):978-81-224-2323-5PUBLISHING FOR ONE WORLDNEW AGE INTERNATIONAL(P)LIMITED,PUBLISHERS4835/24,Ansari Road,Daryaganj,New Delhi-110002Visit us at DharmN-high/hg-tit.pm5?THIS PAGE ISBLANKPreface to the Second Edition“High Voltage Engineering”has been written for the undergraduate students in Electri-cal Engineering of Indian and foreign Universities as well as the practising electricalengineers.The author developed interest in the field of High Voltage Engineering when he was astudent at the Govt.Engineering College,Jabalpur.It used to be thrilling to observe largemetal spheres flashing over,corona phenomenon on a wire placed along the axis of acylinder and then recording the corona loss,controlling the wave shapes of impulse voltagesetc.The author has taught the subject at the Delhi College of Engineering for quite a numberof years and while preparing lecture notes he referred to some of the books and journalsand some literature from the internationally famed manufacturers of High Voltageequipments e.g.Haefely,Tettex etc.The lecture notes so prepared,thus,have a touch ofboth the class room requirements and a practising engineers requirements.In this edition,zeroth chapter on Electric Stress estimation and c ontrol has been addedwhere in different methods viz.finite difference,finite element,charge simmulation methodand surface charge simulation methods have been discussed per estimation of metricstresses in complex dielectric media and electrode configuration.a brief view of optimisationof electrode configuration is also given in this chapter.Chapter 1 deals with the breakdown of gases,liquids,and solid materials.Even though ithas not been possible to explain the physical phenomenon associated with breakdown ofthe materials,with accuracy and precisiveness,an attempt has been made to bring outsome of the theories advocated by researchers in this field in a simple lucid and organisedway.Chapters 2 and 3 discuss the generation of high d.c.and a.c.voltages and high impulsevoltages and currents.Some of the latest circuits have been discussed and rigorous math-ematical treatment of the circuit has been given to make the subject more interesting andto make the student understand the subject better.Measurement of transient voltage and currents and high voltage and current require dif-ferent skills and equipment as compared with common a.c.or d.c.voltages we normallycome across.Chapter 4 discusses various techniques and circuits for measurement of suchquantities.Chapter 5 deals into high voltage testing of electrical equipments like insulators,cables,transformers,circuit breakers etc.The measurements using high voltage Schering bridge,transformer ratio arm bridge andpartial discharges yield information regarding the life expectancy and the long term sta-bility or otherwise of the insulating materials.These techniques have been discussed elabo-rately in Chapter 6.These tests are very important both during design and operation ofthe equipments.Electrical transients last for a very short duration but these play a very important role inthe insulation design of power system.Chapter 7 takes a view of various types of tran-sients in power system and suggests classical and more modern statistical methods ofcoordinating the insulation requirements of various equipments of the system and thedevices required for protection of these equipments.In this edition of the book following articles have been added in chapter 1 of the book:(i)Breakdown in SF6 gas and Vacuum.(ii)Insulating materials used in power apparatus.(iii)Application of gases,liquid and solid insulating materials in different power appara-tus.A suitable number of problems have been solved to help understand the relevant theory.At the end,a large number of multiple choice questions have been added to help thereader to test himself.An extensive bibliography will help the reader to locate detailedinformation on various topics of his interest.There are very few High Voltage Laboratories all over the world and the reader may nothave an opportunity to visit such a laboratory.Therefore,a few photoplates have beenadded at suitable locations in the book to give a physical feel of various equipments in awell equipped high voltage laboratory.The author feels that with the inclusion ofphotoplates of high voltage equipments the student as well the practising engineers wouldbe greatly benefited.I wish to express my sincere thanks to M/s Emile Haefely&Co.Ltd.,Switzerland forpermitting inclusion of photoplates in the book which has enhanced the utility of