The second edition of our book, issued in 1995, continued to receive favorable response from our colleagues and is being used as a textbook by universities and in industry courses worldwide. The first edition presented the fundamental theory of protective relaying as applied to individual system components. This concept was continued throughout the second edition. In addition, the second edition added material on generating plant auxiliary systems, distribution protection concepts, and the application of electronic inductive and capacitive devices to regulate system voltage. The second edition also presented additional material covering monitoring power system performance and fault analysis. The application of synchronized sampling and advanced timing technologies using the Global Positioning Satellite (GPS) system was explained.
This third edition takes the problem of power system protection an additional step forward by introducing power system phenomena which influence protective relays and for which protective schemes, applications, and settings must be considered and implemented. The consideration of power system stability and the associated application of relays to mitigate its harmful effects are presented in detail. New concepts such as undervoltage load shedding, adaptive relaying, hidden failures, and the Internet standard COMTRADE and its uses are presented. The history of notable blackouts, particularly as affected by relays, is presented to enable students to appreciate the impact that protection systems have on the overall system reliability.
As mentioned previously, we are gratified with the response that the first and second editions have received as both a textbook and a reference book. Recent changes in the electric power industry have resulted in power system protection assuming a vital role in maintaining power system reliability and security. It is the authors' hope that the additions embodied in this third edition will enable all electric power system engineers, designers, and operators to better integrate these concepts and to understand the complex interaction of relaying and system performance.