Das J. C. - Power System Protective Relaying

Power Systems Handbook

Power Systems Protective Relaying

Volume 4

Series Author
J.C. Das
Power System Studies, Inc., Snellville, Georgia, USA

Volume 1: Short-Circuits in AC and DC Systems: ANSI, IEEE, and IEC Standards

Volume 2: Load Flow Optimization and Optimal Power Flow

Volume 3: Harmonic Generation Effects Propagation and Control

Volume 4: Power Systems Protective Relaying

Volume 4

J.C. Das

CRC Press

Taylor & Francis Group

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2018 by Taylor & Francis Group, LLC

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Library of Congress Cataloging-in-Publication Data

Names: Das, J. C., 1934- author.

Title: Power systems protective relaying / J.C. Das.

Description: Boca Raton : Taylor & Francis, a CRC title, part of the Taylor &

Francis imprint, a member of the Taylor & Francis Group, the academic

division of T&F Informa, plc, [2018] | Includes bibliographical references

and index.

Identifiers: LCCN 2017017946 | ISBN 9781498745505 (hardback : acid-free paper) | ISBN 9781498745512 (ebook)

Subjects: LCSH: Protective relays. | Electric power systems--Protection.

Classification: LCC TK2861 .D33 2018 | DDC 621.31/7--dc23

LC record available at https://lccn.loc.gov/2017017946

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This handbook on power systems consists of four volumes. These are carefully planned and designed to provide state-of-the-art material on the major aspects of electrical power systems, short-circuit currents, load flow, harmonics, and protective relaying.

An effort has been made to provide a comprehensive coverage, with practical applications, case studies, examples, problems, extensive references, and bibliography.

The material is organized with sound theoretical base and its practical applications. The objective of creating this series is to provide the reader with a comprehensive treatise that could serve as a reference and day-to-day application guide for solving the real-world problem. It is written for plasticizing engineers and academia at the level of upper-undergraduate and graduate degrees.

Though there are published texts on similar subjects, this series provides a unique approach to the practical problems that an application engineer or consultant may face in conducting system studies and applying it to varied system problems.

Some parts of the work are fairly advanced on a postgraduate level and get into higher mathematics. Yet the continuity of the thought process and basic conceptual base are maintained. A beginner and advanced reader will equally benefit from the material covered. An underground level of education is assumed, with a fundamental knowledge of electrical circuit theory, rotating machines, and matrices.

Currently, power systems, large or small, are analyzed on digital computers with appropriate software. However, it is necessary to understand the theory and basis of these calculations to debug and decipher the results.

A reader may be interested only in one aspect of power systems and may choose to purchase only one of the volumes. Many aspects of power systems are transparent between different types of studies and analysesfor example, knowledge of short-circuit currents and symmetrical component is required for protective relaying and fundamental frequency load flow is required for harmonic analysis. Though appropriate references are provided, the material is not repeated from one volume to another.

The series is a culmination of the vast experience of the author in solving real-world problems in the industrial and utility power systems for more than 40 years.

Another key point is that the solutions to the problems are provided in Appendix D. Readers should be able to independently solve these problems after perusing the contents of a chapter and then look back to the solutions provided as a secondary help. The problems are organized so these can be solved with manual manipulations, without the help of any digital computer power system software.

It is hoped the series will be a welcome addition to the current technical literature.

The author thanks CRC Press editor Nora Konopka for her help and cooperation throughout the publication effort.

J.C. Das

Protective relaying is an indispensable part of electrical power systems. In modern times, the advancement in protective relaying is being dictated by microprocessor-based multifunction relays (MMPRs); . Cybersecurity is a growing concern for the grid systems.

is devoted to instrument transformers. Here, the CT saturation has taken a step further, documenting the practical limitation of providing required accuracy CTs based on analytical calculations. The advancement made in the digital relays to accommodate CT saturation and inaccuracies and ensure required performance is the recent trend through digital technology.

forms the background of overcurrent coordination. Coordination on instantaneous basis is a new frontier discussed in this chapter with an example for a fully coordinated system based on NEC requirements. The coordination may require change of device ratings, or other system modifications may be necessary.