Setting Koordinasi Relay Arus Lebih pada Sistem Microgrid Berdasarkan Analisis Hubung Singkat Menggunakan ETAP 21.0.1

Abstract

Abstract  —  Short-circuit faults produce overcurrent that must be isolated rapidly without disconnecting healthy parts of the system. This paper focuses on overcurrent relay (OCR) coordination settings in a microgrid model analyzed using ETAP 21.0.1. Coordination is evaluated based on the circuit-breaker operating sequence, time-current characteristic (TCC), pickup current, and relay time delay. Under the initial condition, a fault on the secondary side of TR_SS-03B produces a current of 1.743 kA; however, breakers farther from the fault point operate earlier, and the TCC curves of the protection devices still intersect. The settings are adjusted by modifying the pickup current and time dial so that the device closest to the fault serves as the primary protection, while upstream devices act as backup protection. After the adjustment, the sequence-of-operation record shows that the fault is detected at 80 ms with a current of 45.0 kA, Relay_1 operates at 100 ms, CB_TR at 200 ms, followed by protection stages at 400 ms, 600 ms, and 800 ms, while CB_MT opens at 7581 ms. These results show that graded pickup and operating-time settings improve protection selectivity, reduce the outage area, and maintain supply continuity in healthy parts of the system.