Over current in the transmission system causes the breaking of electricity to the load, causing losses in the transmission network as well as on the customer's electrical energy. The interference can be overcome by installing a protection tool on the transformer. The protective equipment used in Wonosari mainstay is the Over Current Relay. Over current relays are protection releases that will work when interruption occurs with the Circuit Breaker and rele will read the input value of the current value by comparing the values in the setting. The objective of this research is to know the value of setting rele which is in over current relay. The method used is to find parameter data, interfence current and look for tripping time value of each interference. The calculation result from the relay setting can be working time of the relays of the zone in the OCR, the repeater side when there is the smallest disturbance 3500 A with t = 345 ms and the largest disturbance is 7300 A with t = 250 ms, 20 KV side when there is the smallest disturbance 3500 A with t = 648 ms and the largest disturbance is 7300 A with t = 415 ms, side 150 KV when there is the smallest disturbance 3500 A with t = 819 ms, and the biggest disturbance is 7300 A with t = 656 ms
