Water content analysis effect on dielectric breakdown voltage in 500 kv transformer oil using coefficient correlation method

Abstract

Transformer is a vital component in distributing electrical power. The use of transformer oil which is continuously for a long time and not monitored can cause fatal damage to the transformer. This condition triggered by high water content in the transformer oil which causes breakdown voltage failure and electrical short circuit on the transformer. Therefore this study aims to analyze the influence of water content and breakdown voltage on 500 kV transformer oil type Kunlun Ki25x using the coefficient correlation method. The coefficient correlation method is statistical analysis technique used to look for relationships between variables that are quantitative. Two variables are said to be correlated if the changes in one variable will be followed by changes in the other variables regularly in the same direction (positive correlation) or opposite direction (negative correlation). For material testing and analysis data researcher using Megger OTS100AF instrument. This experiment conduct in paiton 9 power plant East Java for 36 month. Based on experimental data result researcher obtained a strong negative correlation value on the relationship of water content and breakdown voltage with the coefficient R = -0.88 on the function y = 0.7692x + 85.733 and it has characteristic that the increase in water content (x) is inversely proportional to increase the dielectric breakdown voltage (y). In addition, it is also known that the increase in transformer oil temperature is directly proportional to the increase in water content with a positive correlation of R = 0.92 at the function y = 0.4208x + 50.155. From the results above, it can be concluded that the parameters of water content and temperature have an impact on the value of the breakdown voltage and the performance of the transformer.