PERANCANGAN KOORDINASI RELE ARUS LEBIH PADA SISTEM LISTRIK INDUSTRI SAMPEL IEEE Std. 242 - 2001 MENGGUNAKAN PROGRAM ETAP POWER STATION 7.5.0

Overcurrent faults in industrial electric systems often occure due to overload and short circuit. An inaccuration of overcurrent relay setting can causes an uncoordination of protection in the system and endangers electrical machines that generally expensive. Relay coordinations in the system IEEE Std. 242 � 2001 are designed using ETAP software. Settings of each relay can be determined, then simulated a fault to evidence the relay coordination. Characteristics of electrical machines in the system are important to be considered at settings of relay. The successful analysis of relay coordination which doesn�t break over characteristics of electrical machines is by determining a criteria of success. The relay coordination is success when if a fault happens in one-bus, relay will trip started from nearest which doesn�t exceed prtotected capability limits of electrical machines wherever it can. Simulations at each bus indicate that the relay coordinations in the system have been success. The nearest relays to the fault source trip at first time with time delay between 10 ms to 2.035 seconds and appropriate with kind and magnitude of fault current. The farthest relays to the fault source trip at last time with time delay 1.232 seconds to 85.588 seconds