PERFORMANCE ANALYSIS OF MICOM P643 DIFFERENTIAL RELAY ON TRANSFORMER IV OF SEGOROMADU SUBSTATION USING ETAP 21.0.1 SIMULATION: ANALISIS KINERJA RELAI DIFFERENTIAL MICOM P643 PADA TRAFO IV GARDU INDUK SEGOROMADU MENGGUNAKAN SIMULASI ETAP 21.0.1

Andi Wijaya (Universitas PGRI Adi Buana Surabaya)
Sagita Rochman (University of PGRI Adi Buana Surabaya)
Mohamad Ilham (University of PGRI Adi Buana Surabaya)

Jurnal Qua Teknika
Vol 16 No 02 (2026): September 2026

 This study evaluates the differential relay settings of Transformer IV at Segoromadu Substation to ensure reliable transformer protection. The analysis involves manual calculations of transformer nominal current, current transformer (CT) ratio, differential current, restraining current, and relay slope. The results are compared with the existing relay settings and verified through simulations using ETAP 21.0.1. The findings indicate that the existing pickup setting of 0.3 p.u. is appropriate based on the manual calculations. Furthermore, the simulation results demonstrate that the differential relay operates rapidly and selectively, with a trip time of less than 100 ms during internal faults. The relay remains stable during external faults outside the protection zone, confirming its ability to distinguish internal faults from external disturbances and support reliable transformer protection.