Relays and Instrument Transformers in Protecting Power Systems

This book describes relays, instrument current transformer, and instrument voltage transformer. These three devices are the basic building blocks of protective relaying. Each description also shows the mathematics of a device from which its operation or mechanism can be inferred.

After their description, the book shows step-by-step procedures on how they are used in protecting electrical lines, busses, and equipment such as generators and transformers. The book also shows strategies in designing overlapping protective schemes to ensure the safety and of a power system.

Modern protective relaying uses digital microprocessors. While they have more capabilities, understanding relays and instrument transformers still occupies prime importance in successful design of protective relaying.