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.

Gas Production by Monoester of Saturated Fatty Acids under Electrical Fault

“…The oil is undergoing intensive research to be implemented in a power transformer that typically utilizes a high voltage. Other researchers developed monoester type insulating oil from vegetable oil, such as methyl ester and isopropyl ester [5][6][7]. The need for a diagnosis method to assess their performance is essential [8].…”

Monoesters for transformer insulating liquid

“…An attempt to produce methyl esters having a high saturated fatty acids content was made by fractionating the oils based on the melting point difference between saturated and unsaturated fatty acid components [17]. Another attempt was synthesizing isopropyl esters from isopropyl alcohol and myristic, palmitic, and stearic acids [18]. However, both attempts result in the monoesters having higher water content and acid number.…”

“…The resulted oils are also less stable to oxidation than the mineral oil. Nine monoesters were prepared in the current investigation, as in [18]. Treatments were performed to reduce the water and the acid contents and improve the monoesters' oxidation stability.…”