Relay coordination for distribution system

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. The objective of protective relay coordination is to achieve selectivity without loosening sensitivity and quick fault clearance time. 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. Thus the relay coordination problem is formulated, for a real time distribution system is simulated using ETAP.