Temperature Dielectric Spectrum Analysis of Soybean Ester Nanofluid, Mineral Oil and Soybean Ester Impregnated-Papers

Abstract

Research is being directed towards developing a suitable alternative for mineral oil based transformer liquid insulation because of its many demerits. Mineral transformer oil have low flash and fire points, so there is a risk of fire, especially in industrial areas. It is also non-biodegradable and harmful to environment. Mineral oil is also a non-renewable resource. Vegetable oils have proven to be good substitutes for mineral oil particularly due to their high flash and fire points and their biodegradability. By adding suitable nano-particles to vegetable oils, their stability and other thermal and dielectric properties can be improved. Compatibility of these developed oils with paper insulation used in transformers is very important. Temperature dielectric spectrum helps to study the effect of temperature on the dielectric properties of developed oils. In this paper, the Temperature Dielectric Spectrum of transformer insulation paper impregnated with mineral oil, soybean ester and soybean ester based nanofluid with alumina nano-particles is studied using Wayne Kerr Eurotherm and impedance analyzer. From the experiments, it can be concluded that: Relative permittivity (e) of vegetable oil impregnated papers are higher than that of mineral oil impregnated papers. Relative permittivity is highest for soybean ester nanofluid. This property helps in reduction of transformer size. Dissipation factor (tanδ) of vegetable oil impregnated papers is lower compared to that of mineral oil and tanδ is lowest for soybean ester nanofluid.