STUDI KOORDINASI SETTING OCR DAN DGR TRANSFORMATOR 2 DI PLN UP3 SURABAYA UTARA

Abstract

The protection system aims to safeguard electrical equipment from technical disturbances, natural events, operational errors, and other factors. In this research, an analysis and simulation of protection coordination were conducted at the 150 kV Kenjeran Substation of PT PLN (Persero), using data from PLN UP3 North Surabaya. A common issue that arises is a short-circuit disturbance due to improper settings on the Overcurrent Relay (OCR) or Directional Ground Relay (DGR). Parameter values such as OCR Time Multiplier Setting (TMS OCR) and DGR instantaneous current undergo changes in both existing and resetting conditions. Several values differ between the existing and resetting conditions. One such value is the TMS OCR, which originally had a value of 0.15 but becomes 0.18 - 0.24, with varying values for each feeder. The instantaneous current value, previously at 2800 A, becomes 2886.75 A. The existing condition of TMS DGR is 0.2, while the calculated value is 0.0498553. In the existing condition, the instant current of DGR is 4 A, whereas the calculated value is 11.475 A. Subsequently, the creation of an electrical system model using ETAP 19 software was carried out for simulation purposes. The simulation results indicate that when a short-circuit disturbance occurs in a feeder, the relevant relay located in that feeder functions properly, while relays in other feeders do not detect the pickup current as observed in the affected relay. Therefore, it can be concluded that the simulation runs normally.