Analisis Sistem Pengamanan Penyulang pada Transformator Daya di Gardu Induk 150 Kv Mrica

The electric power system is a part of the distribution system used to transmit electrical energy from the plant to the consumer. The electric distribution system is not separated from interference. That is what makes PT. PLN suffered a loss in material form. One of the most frequent disturbances is the short circuit. So we need a protection system that can secure and protect the electricity distribution system. Selectivity, sensitivity, reliability and speed are necessary requirements to minimize the interference. The protection system used is the overcurrent relay and the ground fault relay. The relay works if there is an overcurrent in the relay due to short circuit interruptions or overload, which would then instruct the power breaker to be able to open according to its characteristics. The study aims to perform large calculations of short-circuiting currents that occur on any repression. Then done simulation on ETAP 12.6 software by creating a single line diagram and doing simulation. Simulated results are performed on each reconnection. Then a comparison between simulated results with data contained in the field. Based on the results of the simulation, there is the greatest short-circuiting current of 13987 A in the threephase short circuit fault. And the smallest disturbance value is equal to 874 A in the short circuit to the ground. From the overall result of the calculation data and field data is not much different. This can indicate that the relay on each feeder is still working well and according to the setting