Abstract : The purpose of the protective relays and protective relaying systems is to operate the correct circuit breakers so as to disconnect only the faulty equipment from the system as quickly as possible thus minimizing the trouble and damage caused by faults when they do occur.

Relays have revolutionized protection control metering and communication in power systems. Relay co-ordination will help to isolate the faulty region in the power system so that the fault at a particular region will not affect the other region in the system.

Relay co-ordination can be done by selecting proper PSM and tsm of the relay and co-ordination can be checked graphically .

Relay coordination in a power system will help to prevent the great loss and hazards caused due to the faulty conditions. Relays are also used to protect the transformer and motors also.

Calibration of such relays are also done and also checked whether the relays are co-ordinated in each plant in FACT.

Please find the following attachments"Relay coordination seminar report/pdf download" here.......