Comparative Analysis between Mineral Oil and Vegetable Oil used as Dielectrics and Refrigerants for Power Transformers

Abstract

The objective of this investigation is to evaluate the properties of vegetable oil and mineral oil used as dielectrics and refrigerants in power transformers, equipment that is used on the oil fields exploitation. Based on the ASTM D1524 standard, a visual test was carried out with five samples of each oil, obtaining average values of 1,15 and 0,6 for vegetable oil and mineral oil, respectively. The obtained results showed that vegetable oil keeps its properties for a long time, which extends the equipment's useful life. For the dielectric strength test, according to the ASTM D1816 test, five measurements were taken for the vegetable oil, obtaining as average values 32,9, 29,6, 31,1, 30,7, 32,6; meanwhile, for the mineral oil, the average results of the five measurements were 31,2, 28,5, 29,6, 28,9, 30. It demonstrated that the vegetable oil is better due to it has higher dielectric strength.