This volume examines the fundamentals of protection relays while incorporating current developments in the field. Exploring technical changes in the design of protective systems, the practical concerns of power system protection encountered by users, and the protection requirements for various areas, it discusses the basic technology behind the applications. This edition includes protection requirements for generators, important technologies in microprocessor applications, and protection issues, such as capacitor bank protection, underfrequency and undervoltage load shedding, and DC tripping scheme designs.