Analysis of Differential Relay Performance in the Bakaru Hydroelectric Power Transformer Protection System

Abstract

English

A differential relay is a piece of equipment installed on both terminals of a power transformer coil to detect abnormal operating conditions in a power plant. Its function is to detect disproportionate differences in current flowing at both ends of the power transformer coil terminals as an indicator of a disturbance in the power transformer. Next, it sends a signal to the power breaker, thereby cutting off the power supply to the power transformer. This research aims to determine the correct way to set the differential relay, based on its characteristics so that it can work accurately according to its function. Determining the differential relay settings using the steep point slope. From the analysis, it was found that the slope 1 setting was 9.51% and slope 2 was 19.02%, while the installed data (existing) setting slope 1 was 8.87% and slope 2 was 17.74%. Based on determining the differential relay settings using steep point slopes through analysis and existing data on the power transformer, it was found that the differential relay settings from the analysis results were more sensitive with an angle of 5.43° than the installed settings with an angle of 5.02°. Then, when simulated in the ETAP 19.0.1 software, internal and external three-phase short circuit fault currents were obtained, where during an internal short circuit fault, the differential relay on the Bakaru PLTA power transformer immediately worked to detect abnormal conditions/faults in the transformer, whereas in external short circuit fault, the differential relay does not work detecting an abnormal condition/fault outside its working area

Bahasa Indonesia

Relai diferensial adalah salah satu peralatan yang dipasang pada kedua terminal kumparan transformator daya untuk mendeteksi keadaan operasi abnormal dalam suatu pembangkit listirk. Fungsinya mendeteksi perbedaan arus yang tidak proporsional yang mengalir pada kedua ujung terminal kumparan transformator daya sebagai indikator adanya gangguan pada transformator daya. Selanjutnya mengirim sinyal ke pemutus daya, sehingga memutuskan suplai daya pada transformator daya. Penelitian ini bertujuan menentukan cara setting relai diferensial yang tepat, berdasarkan karakteristiknya agar dapat bekerja secara akurat sesuai fungsinya. Penentuan setting relai diferensial menggunakan slope titik curam. Secara analisis didapatkan setting slope 1 sebesar 9,51% dan slope 2 sebesar 19,02% sementara data terpasang (existing) setting slope 1 sebesar 8,87% dan slope 2 sebesar 17,74%. Berdasarkan penentuan setting relai diferensial menggunakan slope titik curam secara analisis dan data terpasang (existing) pada transformator daya, diperoleh bahwa setting relai diferensial dari hasil analisis lebih sensitif dengan sudut 5,43° dari setting terpasang dengan sudut 5,02°. Kemudian saat disimulasikan pada software ETAP 19.0.1, diperoleh arus gangguan hubung singkat tiga fasa internal dan eksternal, dimana pada saat gangguan hubung singkat internal, relai diferensial pada transformator daya PLTA Bakaru langsung bekerja mendeteksi adanya kondisi abnormal/gangguan di dalam trafo, sedangkan pada gangguan hubung singkat eksternal, relai diferensial tidak bekerja mendeteksi adanya kondisi abnormal/gangguan diluar daerah kerjanya

Keywords

• Fault detection
• Power Transformer
• Slope
• Differential Relay
• ETAP Simulation
• Deteksi gangguan
• Transformator Daya
• Relai Diferensial
• Simulasi ETAP