Comparative Analysis of Breakdown Voltage, Temperature Rise, and Production Cost of Using Mineral Oil and Synthetic Ester in 33 MVA 132/33 kV Power Transformers

AB Rendra Khusuma; Agus Indarto; Chairul Hudaya; Rudy Setiabudy; Faiz Husnayain

doi:10.62146/ijecbe.v3i2.139

Authors

AB Rendra Khusuma Department of Electrical Engineering, Universitas Indonesia, Depok 16424, Indonesia
Agus Indarto
Chairul Hudaya Department of Electrical Engineering, Universitas Indonesia, Depok 16424, Indonesia
Rudy Setiabudy
Faiz Husnayain Universitas Indonesia

DOI:

https://doi.org/10.62146/ijecbe.v3i2.139

Keywords:

Synthetic ester oil, mineral oil, breakdown voltage, temperature rise, power transformer

Abstract

In support of achieving the net zero emission target in the power sector, the selection of environmentally friendly transformer insulating oil is very important. This study presents a comparative analysis of the dielectric and thermal performance between mineral oil and synthetic ester oil. The breakdown voltage (BDV) test was conducted with a variation of rest time of 1 minute and 10 minutes. In addition, temperature rise tests were conducted on a 33 MVA capacity power transformer with a voltage of 132/33 kV. Temperature rise testing is carried out on synthetic ester oil and mineral oil through thermal simulation with identical transformer specifications, the goal is that there are no distinguishing variables in the test. The test results show that at a rest time of 1 minute, synthetic ester oil produces fluctuating BDV values, with some data being below the minimum threshold of 60 kV according to IEC 61203 standards. In contrast, mineral oil (MO) showed stable and consistent dielectric performance. At a rest time of 10 minutes, both types of oil showed stable BDV values with low standard deviations. In terms of thermal performance, mineral oil produced a lower temperature rise than synthetic ester oil (SE), indicating better cooling efficiency. The study will also analyze the impact of transformer dimensions due to the different transformer oils used, which will result in the price of the transformer. The findings provide technical insights for manufacturers and users in selecting transformer oils that support environmental sustainability without compromising the reliability of power transformers.

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