Analisa Perhitungan Dan Pengaturan Relai Arus Lebih Dan Relai Gangguan Tanah Pada Trafo III 60MVA 150/20 kV Di Gardu Induk 150kV Palur

Electricity is a source of energy that is needed role in everyday life. Distribution or distribution of electricity can not be separated from a protection system to avoid the risk of disruption that does not cool. Usually a frequent disruption is short circuit interruption where this short circuit can cause damage to electrical equipment as well as losses in electrical transmission systems as well as to consumers as users of electrical energy. Protection system is a way to prevent or limit damage of equipment due to interference, to localize the disturbance required a qualified protection system such as sensitivity, selectivity, fast and reliable that all can be obtained with the accuracy of setting protection equipment. The protective equipment used is the overcurrent relay (OCR) and ground disturbance current relay (GFR) which works to construct the breaker to open when interference occurs. The installed protection equipment shall be coordinated by determining relay operation for any interference in the relay protection area. The analysis is aimed to calculate the amount of short circuit current, determine the relay protection setting and compare it with the relay setting in the field. Based on the results of the calculation, we get the most immediate three-phase short circuit current value is 10689.90 -85 A and the smallest value of short circuit current to ground is 1148.31 -73,9 A. TMS setting values obtained from the calculation results for OCR side 20kV is 0.24, the GFR side of the buffer is 0.192 and the setting for incoming 20kV incoming OCR is 0.25 and GFR of incoming side of 20kV is 0.41. Overall data calculations and existing data field is not much different it can be said relay still in good condition or work according to its setting. Key words:protection, over current relay, setting rela