Short T.A. Electric Power Distribution Handbook

Подождите немного. Документ загружается.

1791_TitlePage 7/9/03 2:45 PM Page 1

CRC PRESS

Boca Raton London New York Washington, D.C.

ElECTRIC POWER

distribution

handbook

T.A. Short

Electric Pwr Eng Series 7/9/03 4:10 PM Page 1

The ELECTRIC POWER ENGINEERING Series

series editor Leo Grigsy

Published Titles

Computational Methods for Electric Power Systems

Mariesa Crow

Distribution System Modeling and Analysis

William H. Kersting

Electric Drives

Ion Boldea and Syed Nasar

Electrical Energy Systems

Mohamed E. El-Hawary

Electric Power Substations Engineering

John D. McDonald

Electric Power Transformer Engineering

James H. Harlow

Electromechanical Systems, Electric Machines,

and Applied Mechatronics

Sergey E. Lyshevski

The Induction Machine Handbook

Ion Boldea and Syed Nasar

Linear Synchronous Motors:

Transportation and Automation Systems

Jacek Gieras and Jerry Piech

Power Quality

C. Sankaran

Power System Operations and Electricity Markets

Fred I. Denny and David E. Dismukes

Electric Power Distribution Handbook

Tom Short

Forthcoming Titles

The Electric Generators Handbook

Ion Boldea

The ELECTRIC POWER ENGINEERING Series

Series Editor Leo L. Grigsby

This book contains information obtained from authentic and highly regarded sources. Reprinted material

is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable

efforts have been made to publish reliable data and information, but the author and the publisher cannot

assume responsibility for the validity of all materials or for the consequences of their use.

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 or

retrieval system, without prior permission in writing from the publisher.

The consent of CRC Press LLC does not extend to copying for general distribution, for promotion, for

creating new works, or for resale. Speciﬁc permission must be obtained in writing from CRC Press LLC

for such copying.

Direct all inquiries to CRC Press LLC, 2000 N.W. Corporate Blvd., Boca Raton, Florida 33431.

Trademark Notice:

Product or corporate names may be trademarks or registered trademarks, and are

used only for identiﬁcation and explanation, without intent to infringe.

Visit the CRC Press Web site at www.crcpress.com

No claim to original U.S. Government works

International Standard Book Number 0-8493-1791-6

Library of Congress Card Number 2003055214

Printed in the United States of America 1 2 3 4 5 6 7 8 9 0

Printed on acid-free paper

Library of Congress Cataloging-in-Publication Data

Short, Tom, 1966–

Electric power distribution handbook / Tom Short.

p. cm. — (Electric power engineering series)

Includes bibliographical references and index.

ISBN 0-8493-1791-6 (alk. paper)

1. Electric power distribution—Handbooks, manuals, etc. I. Title. II. Series.

TK3001.S47 2003

621.319—dc21 2003055214

1791_book.fm Page 4 Monday, August 4, 2003 3:20 PM

Dedication

To the future. To Jared. To Logan.

1791_book.fm Page 5 Monday, August 4, 2003 3:20 PM

Preface

In industrialized countries, distribution systems deliver electricity literally

everywhere, taking power generated at many locations and delivering it to

end users. Generation, transmission, and distribution — of these big three

components of the electricity infrastructure, the distribution system gets the

least attention. Yet, it is often the most critical component in terms of its

effect on reliability and quality of service, cost of electricity, and aesthetic

(mainly visual) impacts on society.

Like much of the electric utility industry, several political, economic, and

technical changes are pressuring the way distribution systems are built and

operated. Deregulation has increased pressures on electric power utilities to

cut costs and has focused emphasis on reliability and quality of electric

service. The great fear of deregulation is that service will suffer because of

cost cutting. Regulators and utility consumers are paying considerable atten-

tion to reliability and quality. Another change that is brewing is the intro-

duction of distributed generation on the distribution system. Generators at

the distribution level can cause problems (and have beneﬁts if properly

applied). Customers are pressing for lower costs, better reliability, and less

visual impact from utility distribution systems.

Deregulation and technical changes increase the need by utility engi-

neers for better information. This book helps ﬁll some of those needs in

the area of electric distribution systems. The ﬁrst few chapters of the book

focus on equipment-oriented information and applications such as choos-

ing transformer connections, sizing and placing capacitors, and setting

regulators.

The middle portion of this handbook contains many sections targeting

reliability and power quality. The performance of the distribution system

determines greater than 90% of the reliability of service to customers (the

high-voltage transmission and generation system determines the rest). If

performance is increased, it will have to be done on the distribution

system.

Near the end, we tackle lightning protection, grounding, and safety. Safety

is a very important consideration in the design, operation, and maintenance

of distribution facilities. The last chapter on distributed generation provides

information to help utilities avoid problems caused by the introduction of

distributed generation.

I hope you ﬁnd useful information in this book. If it is not in here, hopefully

one of the many bibliographic references will lead you to what you are

looking for. Please feel free to email me feedback on this book including

errors, comments, opinions, or new sources of information. I would like to

1791_book.fm Page 7 Monday, August 4, 2003 3:20 PM

hear from you. Also, if you need my help with any interesting consulting or

research opportunities, I would love to hear from you.

Tom Short

EPRI PEAC

Schenectady, New York

t.short@ieee.org

1791_book.fm Page 8 Monday, August 4, 2003 3:20 PM

Foreword

The public proﬁle of electricity and those who provide it is likely to dramatically

increase. Unlike the industrial analog economy of the 20th century, the net-

worked digital economy only runs on electricity — that is, a perfect stream of

electrons seamlessly linked with a real-time ﬂow of information. Productivity

and competitive advantage depend on rapidly facilitating this transformation.

The challenges of the digital economy come at a time of rapid change for

the electric power industry and especially for its power delivery system.

Meanwhile, many areas are now considering ways to increase competition

in retail markets and provide customers with greater choice among electricity

providers. The capability of the power delivery system, however, has not

kept up with the new demands brought by deregulation. Most transmission

and distribution systems were designed more than a half-century ago, when

long-distance power transfer was used mainly for economic exchange

among a few utilities and when the reliability requirements of distribution

systems were much less severe than in a digital economy. So far, the needed

improvements in both capacity and reliability have not been made.

While utility loads have grown and users are more demanding, the dis-

tribution infrastructure has not kept pace. Consider the period from 1989 to

1999 when total electricity demand in the U.S. rose by nearly 30% — over

the same period, expenditures by investor-owned utilities for distribution

system construction fell by about 10% in real terms (based on data from

EEI’s

Statistical Yearbook

, 1999).

Mr. Short’s handbook provides many tools to help address the challenges

of providing a more reliable distribution system given signiﬁcant cost con-

straints. In addition to a wealth of classic information on distribution prac-

tices, his handbook provides new insights based on recent research by EPRI,

the Consortium for Electric Infrastructure to Support a Digital Society

(CEIDS), IEEE, and others.

As someone who started his utility career as an electrician, I appreciate

the practical advice provided by this handbook. While the book has leading-

edge research and a great deal of in-depth technical information, it also

manages to offer considerable practical information. As a former practitioner,

I also appreciate the handbook’s consideration of issues affecting safety.

This handbook is a ﬁne addition to CRC Press’s Electric Power Engineering

Series, which distribution engineers should ﬁnd useful for many years.

Clark W. Gellings, PE

Vice President — Power Delivery and Markets

EPRI

Palo Alto, California

1791_book.fm Page 9 Monday, August 4, 2003 3:20 PM

Acknowledgments

First and foremost, I would like to thank my wife Kristin — thank you for

your strength, thank you for your help, thank you for your patience, and

thank you for your love. My play buddies, Logan and Jared, energized me

and made me laugh. My family was a source of inspiration. I would like to

thank my parents, Bob and Sandy, for their inﬂuence and education over

the years.

EPRI PEAC provided a great deal of support on this project. I would like

to recognize the reviews, ideas, and support of Phil Barker and Dave Crudele

here in Schenectady, New York, and also Arshad Mansoor, Mike Howard,

Charles Perry, Arindam Maitra, and the rest of the energetic crew in Knox-

ville, TN.

Many other people reviewed portions of the draft and provided input and

suggestions, including Dave Smith (Power Technologies, Inc.), Dan Ward

(Dominion Virginia Power), Jim Stewart (Consultant, Scotia, NY), Conrad

St. Pierre (Electric Power Consultants), Karl Fender (Cooper Power Sys-

tems), John Leach (Hi-Tech Fuses, Inc.), and Rusty Bascom (Power Delivery

Consultants).

Thanks to Power Technologies, Inc., for opportunities and mentoring dur-

ing my early career with the help of several talented, helpful engineers,

including Jim Burke, Phil Barker, Dave Smith, Jim Stewart, and John Ander-

son. Over the years, several clients have also educated me in many ways;

two that stand out are Ron Ammon (Keyspan, retired) and Clay Burns

(National Grid).

EPRI has been supportive of this project, including a review by Luther

Dow. EPRI has also sponsored a number of interesting distribution research

projects that I have been fortunate enough to be involved with, and EPRI

has allowed me to share some of those efforts here.

As a side-note, I would like to recognize the efforts of linemen in the

electric power industry. These folks do the real work of building the lines

and keeping the power on. As a tribute to them, a trailer at the end of each

chapter reveals a bit of the lineman’s character and point of view.

1791_book.fm Page 11 Monday, August 4, 2003 3:20 PM

Credits

Tables 4.3 to 4.7 and 4.13 are reprinted with permission from IEEE Std.

C57.12.00-2000.

IEEE Standard General Requirements for Liquid-Immersed Dis-

tribution, Power, and Regulating Transformers.

Figure 4.17 is reprinted with permission from ANSI/IEEE Std. C57.105-

1978.

IEEE Guide for Application of Transformer Connections in Three-Phase

Distribution Systems.

Tables 6.2, 6.4, and 6.5 are reprinted with permission from IEEE Std. 18-

2002.

IEEE Standard for Shunt Power Capacitors.

Table 6.3 is reprinted with permission from ANSI/IEEE Std. 18-1992.

IEEE

Standard for Shunt Power Capacitors.

Table 7.9 is reprinted with permission from IEEE Std. 493-1997.

IEEE Rec-

ommended Practice for the Design of Reliable Industrial and Commercial Power

Systems (Gold Book).

Table 8.3 is reprinted with permission from IEEE Std. C37.112-1996.

IEEE

Standard Inverse-Time Characteristic Equations for Overcurrent Relays.

Copy-

right 1997 by IEEE.

Tables 11.1 to 11.3 are reprinted with permission from IEEE Std. 519-1992.

IEEE Recommended Practices and Requirements for Harmonic Control in Electrical

Power Systems.

Figure 11.19 is reprinted with permission from IEEE Std. 141-1993.

IEEE

Recommended Practice for Electric Power Distribution for Industrial Plants.

Copy-

right 1994 by IEEE.

Tables 12.4 and 12.5 are reprinted with permission from IEEE Std. C62.22-

1997.

IEEE Guide for the Application of Metal-Oxide Surge Arresters for Alter-

nating-Current Systems.

Figure 12.16 is reprinted with permission from IEEE Std. 4-1995.

IEEE

Standard Techniques for High-Voltage Testing.

Figure 12.19 is reprinted with permission from IEEE Std. 1299/C62.22.1-

1996. IEEE Guide for the Connection of Surge Arresters to Protect Insulated,

Section 12.7.2.1 is reprinted with permission from IEEE Std. 1410-1997.

IEEE Guide for Improving the Lightning Performance of Electric Power Overhead

Distribution Lines

Tables 13.3 and 13.4 are reprinted with permission from IEEE Std. 142-

1991.

IEEE Recommended Practice for Grounding of Industrial and Commercial

Power Systems.

Figure 13.15 is reprinted with permission from IEEE Std. 80-2000.

IEEE

Guide for Safety in AC Substation Grounding

The IEEE disclaims any responsibility or liability resulting from the place-

ment and use in the described manner.

1791_book.fm Page 13 Monday, August 4, 2003 3:20 PM

Contents

Fundamentals of Distribution Systems

1.1 Primary Distribution Conﬁgurations

1.2 Urban Networks

1.3 Primary Voltage Levels

1.4 Distribution Substations

1.5 Subtransmission Systems

1.6 Differences between European and North American Systems

1.7 Loads

1.8 The Past and the Future

References

Overhead Lines

2.1 Typical Constructions

2.2 Conductor Data

2.3 Line Impedances

2.4 Simpliﬁed Line Impedance Calculations

2.5 Line Impedance Tables

2.6 Conductor Sizing

2.7 Ampacities

2.7.1 Neutral Conductor Sizing

2.8 Secondaries

2.9 Fault Withstand Capability

2.9.1 Conductor Annealing

2.9.2 Burndowns

2.10 Other Overhead Issues

2.10.1 Connectors and Splices

2.10.2 Radio Frequency Interference

References

Underground Distribution

3.1 Applications

3.1.1 Underground Residential Distribution (URD)

3.1.2 Main Feeders

3.1.3 Urban Systems

3.1.4 Overhead vs. Underground

3.2 Cables

3.2.1 Cable Insulation

3.2.2 Conductors

1791_book.fm Page 15 Monday, August 4, 2003 3:20 PM