Table Of Content1791_TitlePage 7/9/03 2:45 PM Page 1
ElECTRIC POWER
distribution
handbook
T.A. Short
CRC PR ESS
Boca Raton London New York Washington, D.C.
(C) 2004 by CRC Press LLC
Electric Pwr Eng Series 7/9/03 4:10 PM Page 1
ThThee E ELLEECCTTRRIICC PPOOWWEERR EENNGGIINNEEEERRIINNGG SSeerireises
Sesreierise sE deidtoitro rL eLoe oL .G Grrigigssyby
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
(C) 2004 by CRC Press LLC
1791_book.fm Page 4 Monday, August 4, 2003 3:20 PM
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
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
© 2004 by CRC Press LLC
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
(C) 2004 by CRC Press LLC
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Dedication
To the future. To Jared. To Logan.
(C) 2004 by CRC Press LLC
1791_book.fm Page 7 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
(C) 2004 by CRC Press LLC
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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
[email protected]
(C) 2004 by CRC Press LLC
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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
(C) 2004 by CRC Press LLC
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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.
(C) 2004 by CRC Press LLC
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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. Copyright 2000 by IEEE.
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. Copyright 1978 by IEEE.
Tables 6.2, 6.4, and 6.5 are reprinted with permission from IEEE Std. 18-
2002. IEEE Standard for Shunt Power Capacitors. Copyright 2002 by IEEE.
Table 6.3 is reprinted with permission from ANSI/IEEE Std. 18-1992. IEEE
Standard for Shunt Power Capacitors. Copyright 1993 by IEEE.
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). Copyright 1998 by IEEE.
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. Copyright 1993 by IEEE.
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. Copyright 1998 by IEEE.
Figure 12.16 is reprinted with permission from IEEE Std. 4-1995. IEEE
Standard Techniques for High-Voltage Testing. Copyright 1995 by IEEE.
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,
Shielded Electric Power Cable Systems. Copyright 1997 by IEEE.
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. Copyright 1997 by IEEE.
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. Copyright 1992 by IEEE.
Figure 13.15 is reprinted with permission from IEEE Std. 80-2000. IEEE
Guide for Safety in AC Substation Grounding. Copyright 2000 by IEEE.
The IEEE disclaims any responsibility or liability resulting from the place-
ment and use in the described manner.
(C) 2004 by CRC Press LLC
1791_book.fm Page 15 Monday, August 4, 2003 3:20 PM
Contents
1 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
2 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
3 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
(C) 2004 by CRC Press LLC
