Preliminary results on the development of monoester type insulating oil from coconut oil

Abstract

Vegetable oils, both in tri-ester and monoester forms have been attractive alternative substitutes for replacing mineral oil as the insulating liquid used in power transformer. An effort to develop a monoester type insulating oil derived from coconut oil has been conducted, and the preliminary results of the development are reported in this paper. Five different samples were prepared from methyl ester of coconut oil based on their melting point. The important properties of oil samples such as viscosity, water content, acidity, and density were tested, and are evaluated based on the standard specification of natural ester used for the transformer. Another fundamental property, i.e., oxidation stability was also tested and is evaluated by comparing the corresponding result of mineral oil. It is found that oil needs further treatment before being able to be used as insulating oil.

Filtration and water reduction of methyl ester for insulation purpose

“…An attempt to develop a low viscosity insulating oil from monoester derived from natural ester, especially methyl ester is being conducted in our Laboratory. Our preliminary results [15] show that the viscosity and the density of the methyl ester comply well with the standard specification of as-received natural ester used for an oil-filled transformer, ASTM D 6871 [16]. In the current work presented in this paper, two kinds of treatments to improve the quality of the methyl ester have been made, namely filtration and water reduction.…”