Optimalisasi Penggunaan Electronic Over Current Relay Sebagai Proteksi Lebih Arus Pada Motor 55 KW Di Sistem Cooling Tower Pt Indah Kiat Pulp & Paper Perawang

Three-phase induction motors are among the primary electrical machines widely used in industrial applications, including the cooling tower system at PT Indah Kiat Pulp & Paper Perawang. The reliability of these motors is highly dependent on an effective protection system against overcurrent faults. The use of an Electronic Over Current Relay (EOCR) offers several advantages over a Thermal Overload Relay (TOR),including more comprehensive protection features, real-time current monitoring, and adjustable trip-time settings. This study aims to determine the optimal EOCR settings to provide effective overcurrent protection while minimizing unnecessary tripping. This research employed an observational and analytical method consisting of field observations, literature review, data collection of motor and EOCR specifications, current and voltage measurements, nominal current calculations, EOCR setting determination, and performance evaluation after optimization. The object of this study was a 55 KW ABB M2QA250M4A three-phase induction motor used in the cooling tower system at PT Indah Kiat Pulp & Paper Perawang. The results showed that, based on the motor nameplate data of 55 KW output power, 380 V operating voltage, 0.88 power factor, and 92% efficiency, the calculated nominal current was 103.13 A. By applying a 10% safety margin, the appropriate EOCR overcurrent setting was determined to be 113 A, replacing the previous setting of 90 A. Field measurements indicated that the motor operated with phase currents ranging from 45.1 A to 46.2 A and line voltages ranging from 392.8 V to 394.2 V, indicating that the motor was operating at approximately 43.73% of vii its rated capacity. After optimization, the EOCR parameters were configured as follows: Over Current (OC) = 113 A, Delay Time (DT) = 5 seconds, Operation Time (OT) = 5 seconds, Phase Loss (PL) = ON, Unbalance (UB) = 30 seconds, and Short Circuit (SC) = 5 seconds. These settings improved the reliability of the motor protection system, reduced unnecessary trips, and provided better protection against overload, phase loss, current unbalance, and short-circuit faults.