Analisis Koordinasi Over Current Relay Dan Ground Fault Relay Terhadap Keandalan Sistem

Abstract

This research had done base on case study in the feeder of substation 20 kV Jababeka. Existing data showed that condition is well with not too long differential, over all setting on the Overcurrent Relay (OCR) – Ground Fault Relay (GFR) in the field is well. From calculated result can be seem that current of short circuit disturb is influenced by distance between disturbance points. Using over current relay has important purpose in the protection of electricity system. The qualification need setting minimum time of over current relay in the feeder not less than 0.3 second. This consider to the relay will not in trip condition in rush current from distribution transformator that has been connected in the distribution system when the feeder starts operated. Starting time for relay in the feeder is faster than work time in the incoming side with average time about 0.4 second for one phase disturbance side. But for three phase and two phase disturbance side, work time relay has interval time about 0.4 second and than increase with average increament about 0.1 second when transmission line is longer (from distance aspects about 0%, 25%, 50%, 75% and 100%).