he relay co-ordination is nothing but a tripping of protecting relay in a sequence or order in electrical power system. Relay coordination is very difficult task for relay engineers. Relay co-ordination is required to isolate the faulty part with minimized relay & circuit breaker operation.

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 specially designed Softwares