Analisa Penggunaan Rele Differensial Sebagai Proteksi Pada Transformator 60 MVA Di Gardu Induk Palur

Power transformers are the most important component and need to be protected from interference that could disrupt the supply of electricity. Differensial relay is the principle it works on the basis of the balance, which compares the current transformer secondary currents (CT) is installed on the terminals equipment or electrical installation which is secured. The success of differnsial relay protection is the precision of setting releases to prevent protection failures and to improve transmission system reliability. The method used in this study is secondary data recycling by conducting a 30-day research on the Palur Substation and looking for reference journals that are related to the research. All data obtained then processed by calculation manually. The calculation includes the value of current transformer ratio, error mismatch, and differnsial release parameters. The result of the calculation of current transformer ratio value is on the high-voltage side of the ratio 300: 1 A while for the low voltage is 2500: 1. The result obtained from the calculation of the rating current rating is on the high voltage side is 254,034 A and at the low voltage side 1.905,255 A. Mismatch error value at high voltage is 1,11% and 0,9% at low voltage. Furthermore the value of the secondary current is 0,769 A on the high voltage side and 0,692 A on the low voltage side. Differential current get result 0,077 A, while restrain current is 0,730 A. Current setting result of calculation is 0,1 A with hope of protection system can run optimally