In power system protection relay and circuit breakers is the major instrument for large interconnected power system. We need proper protection to isolate the faulted region from healthier network. When two protective apparatus installed in series have certain characteristics, which provide a specified operating sequence, they are said to be coordinated or selective. Relay coordination is an important aspect in the protection system design as coordination schemes must guarantee fast, selective and reliable relay operation to isolate the power system faulted sections.

Why is Relay Coordination study and Analysis performed?

Relay coordination study and analysis is performed to make sure that safety operation of the system are  functioning correctly and to avoid the nuisance tripping; as protection is a major concern in any industry and they rely on protective devices of the same. The reason for nuisance tripping is modification of protective devices and their setting at the time of upkeep without performing suitable study and analysis.