Analisa Kelayakan Tahanan Isolasi Transformator 150 KV GT 1.1 Menggunakan Indeks Polarisasi, Tan Delta, Dissolved Gas Analysis, dan Breakdown Voltage di PLTGU UPDK Belawan

Abstract

The transformer is the main component of electric power distribution which functions to distribute electric power from high voltage to low voltage or vice versa. Therefore, the power transformer being operated must be in good condition. To prevent operational failure and damage due to overvoltage, humidity, temperature or mechanical damage, insulation resistance testing is carried out. There are 4 tests carried out, is: Polarity Index test, tangent delta test, dissolved gas analysis test, and breakdown voltage test which determines the suitability of the transformer. The object studied is the GT 1.1 Main Transformer PLTGU Belawan transformer. The data obtained includes the results of the four test methods. In this method, data is processed using certain formulas and analyzed using measurement data between variables before and after.The delta tangent test results of the GT 1.1 Transformer obtained results below 0.5%, which is in good condition in accordance with the ANSI C57.12.90 standard. The DGA test results of the GT 2.1 Transformer using the TDCG method stated that the dissolved gas concentration in the transformer oil was in good condition according to with IEC 60076-01 standards, even though there is Overhead Cellulos interference. The results of the transformer Breakdown Voltage (BDV) test stated that the breakdown voltage on the transformer was in good condition or still within the permitted limits according to the 50 KV voltage limit in the IEC 60076-01 standard. The Polarization Index test results obtained results above 1.5 in a condition of adequate tolerance according to IEC 60076-3 standards. The results of testing the quality of the isolation resistance of the GT 1.1 transformer at PLTGU UPDK Belawan using the four methods described show that the condition of the transformer's insulation resistance is suitable for operation.