PERHITUNGAN SETTING RELE ARUS LEBIH PADA TRANSFORMATOR DAYA SISI 20 kV DI GARDU INDUKTALANG RATU

ABSTRACT The distribution transformer is the main equipment for distributing electrical power from high voltage to medium voltage. In pengoperasiaanya not always run normally, but sometimes the occurrence of interference that may result in reduced reliability and if not addressed soon can cause damage to the equipment. Therefore a protection system is required to secure the equipment from interference. One of the protective devices used is the overcurrent relay. In order to meet the reaction speed and selectivity then the more current relay used for securing the transformer must be adjusted (setting) appropriately. More current relay settings include current and time setting. The current adjustment shall be adjusted to the maximum capacity of the transformer to be secured and the adjustment procedures adjusted to the type of release used by the investigation carried out through the design and calculation of the case study at GITalangRatu PT PLN Persero. The calculation result for its mominal current is 866,025 A. The current tuning calculation on this overcurrent relay is 4.76 A, while the determination of the operation time is 0.5 s so the calculation of the time setting is 0.043