Preliminary Study on the Basic Characteristics of Isopropyl Esters Used As Insulating Liquid

Abstract The paper presents the basic properties evaluation of isopropyl esters for an insulating liquid in oil-filled transformer. Two kinds of isopropyl esters, namely, isopropyl palmitate and isopropyl stearate, were synthesized from isopropyl alcohol and palmitate and stearate acids. The resulted isopropyl esters were then evaluated for their basic properties such as breakdown voltage, viscosity, density, acidity, and water-based on the ASTM D 6871 standard specification. The investigation results show that the viscosity and the Density of both isopropyl esters meet the standard’s values well. The breakdown voltage of isopropyl stearate is higher than the standard specification, whereas that of isopropyl palmitate is less than the standard value. The water content of both liquids is still much higher than the value specified by the standard.