Breakdown characteristic of natural ester gelling process under oxidation and its impact on fresh oil

Abstract

Natural ester as an environmentally friendly dielectric liquid is becoming commonly used in power transformer. However, it is susceptible to oxidation. Under severe oxidation, the oil sample could gel whose impact on insulation performance is not known. In this research, we focus on the impact of the gelling process of natural ester on its breakdown characteristics. In order to survey this, a breakdown test platform was first assembled. Then the experiment was conducted, with the results showing that the gelling procedure includes three stages, the liquid, the sol and the gel. The sol was found to show a poor breakdown performance and also impact the breakdown performance of the fresh oil if it is dissolved. The gel, more in a solid form similar to jelly, showed slightly a higher breakdown performance itself but slightly impacted the fresh oil under mixture.