eBook - ePub
Protective Relaying
Principles and Applications, Fourth Edition
This is a test
- 695 pages
- English
- ePUB (mobile friendly)
- Available on iOS & Android
eBook - ePub
Book details
Book preview
Table of contents
Citations
About This Book
For many years, Protective Relaying: Principles and Applications has been the go-to text for gaining proficiency in the technological fundamentals of power system protection. Continuing in the bestselling tradition of the previous editions by the late J. Lewis Blackburn, the Fourth Edition retains the core concepts at the heart of power system anal
Frequently asked questions
At the moment all of our mobile-responsive ePub books are available to download via the app. Most of our PDFs are also available to download and we're working on making the final remaining ones downloadable now. Learn more here.
Both plans give you full access to the library and all of Perlegoâs features. The only differences are the price and subscription period: With the annual plan youâll save around 30% compared to 12 months on the monthly plan.
We are an online textbook subscription service, where you can get access to an entire online library for less than the price of a single book per month. With over 1 million books across 1000+ topics, weâve got you covered! Learn more here.
Look out for the read-aloud symbol on your next book to see if you can listen to it. The read-aloud tool reads text aloud for you, highlighting the text as it is being read. You can pause it, speed it up and slow it down. Learn more here.
Yes, you can access Protective Relaying by J. Lewis Blackburn, Thomas J. Domin in PDF and/or ePUB format, as well as other popular books in Technology & Engineering & Electrical Engineering & Telecommunications. We have over one million books available in our catalogue for you to explore.
Information
Chapter 1
Introduction and General Philosophies
1.1 Introduction and Definitions
What is a relay; more specifically, what is a protective relay? The Institute of Electrical and Electronic Engineers (IEEE) defines a relay as âan electric device that is designed to respond to input conditions in a prescribed manner and, after specified conditions are met, to cause contact operation or similar abrupt change in associated electric control circuits.â A note adds: âInputs are usually electric, but may be mechanical, thermal, or other quantities or a combination of quantities. Limit switches and similar simple devices are not relaysâ (IEEE C37.90, 1989).
Relays are used in all aspects of activity: home, communication, transportation, commerce, and industry, to name a few. Wherever electricity is used, there is a high probability that relays are involved. They are used in heating, air conditioning, stoves, dishwashers, clothes washers and dryers, elevators, telephone networks, traffic controls, transportation vehicles, automatic process systems, robotics, space activities, and many other applications.
In this book we focus on one of the more interesting and sophisticated applications of relays, the protection of electric power systems. The IEEE defines a protective relay as âa relay whose function is to detect defective lines or apparatus or other power system conditions of an abnormal or dangerous nature and to initiate appropriate control circuit actionâ (IEEE 100, 2000).
Fuses are also used in protection. IEEE defines a fuse as âan over-current protective device with a circuit-opening fusible part that is heated and severed by the passage of the overcurrent through itâ (IEEE 100, 2000).
Thus, protective relays and their associated equipment are compact units of analog, discrete solid-state components, operational amplifiers, and digital microprocessor networks connected to the power system to sense problems. These are frequently abbreviated simply as relays and relay systems. They are used in all parts of the power system, together with fuses, for the detection of intolerable conditions, most often faults.
Protective relaying, commonly abbreviated relaying, is a nonprofit, nonrevenue-producing item that is not necessary in the normal operation of an electric power system until a faultâan abnormal, intolerable situationâoccurs.
A primary objective of all power systems is to maintain a very high level of continuity of service, and when intolerable conditions occur, to minimize the outage times. Loss of power, voltage dips, and overvoltages will occur, however, because it is impossible, as well as impractical, to avoid the consequences of natural events, physical accidents, equipment failure, or misoperation owing to human error. Many of these result in faults: inadvertent, accidental connections and flashovers between the phase wires or from the phase wire(s) to the ground.
Natural events that can cause short circuits (faults) are lightning (induced voltage or direct strikes), wind, ice, earthquake, fire, explosions, falling trees, flying objects, physical contact by animals, and contamination. Accidents include faults resulting from vehicles hitting poles or contacting live equipment, unfortunate people contacting live equipment, digging into underground cables, and human errors. Considerable effort is made to minimize damage possibilities, but the elimination of all such problems is not yet achievable.
A dramatic illustration of the need and importance of power system protection is shown in Figure 1.1. This spectacular lightning strike occurred over Seattle during a storm on July 31, 1984, and in a region where lightning is infrequent. The isokeraunic charts for this area of the Pacific Northwest indicate that the probability of storm days when thunder is heard is five or fewer per year (Westinghouse Electric Corp., 1964). Although some 12,000 homes lost power during this storm, neither major damage nor prolonged outages were experienced by the local utilities. Fortunately, lightning protection and many relays operated to minimize the problems.
Figure 1.1
Table of contents
- Preface to the Fourth Edition
- Preface to the Third Edition
- Preface to the Second Edition
- Preface to the First Edition
- Author
- Chapter 1 - Introduction and General Philosophies
- Chapter 2 - Fundamental Units: Per-Unit and Percent Values
- Chapter 3 - Phasors and Polarity
- Chapter 4 - Symmetrical Components: A Review
- Chapter 5 - Relay Input Sources
- Chapter 6 - Protection Fundamentals and Basic Design Principles
- Chapter 7 - System-Grounding Principles
- Chatper 8 - Generator Protection/Intertie Protection for Distributed Generation
- Chapter 9 - Transformer, Reactor, and Shunt Capacitor Protection
- Chapter 10 - Bus Protection
- Chapter 11 - Motor Protection
- Chapter 12 - Line Protection
- Chapter 13 - Pilot Protection
- Chapter 14 - Stability, Reclosing, Load Shedding, and Trip Circuit Design
- Chapter 15 - Microprocessor Applications and Substation Automation
- Chapter 16 - Improving Protective System Performance
- Chapter 17 - Problems