Mineral oil oas ba?adores derived from petroleum is the most preferred liquid insulation and coolant in power and distribution transformers because of its stability at high temperatures, as well as its excellent electrical insulating properties.Since it is non-biodegradable and inflammable, an alternative insulating liquid should be developed, or a possible approach should be established, to further utilize the aged mineral oil in the existing transformers to avoid the problem of discarding the oil.Though natural esters look like a promising alternative, they suffer from excessive oxidation which makes them unsuitable for transformer insulation applications.
This work presents the feasibility of blending aged mineral oil with synthetic ester to extend its life.Both fresh and aged mineral oil were blended with synthetic ester separately using ultrasonication after the removal of moisture content.The electrical, thermal, and physiochemical characteristics of the blended oil were studied by measuring breakdown voltage, flash and fire points, and viscosity, respectively.
These characteristics varied depending upon the ratios of mineral oil and synthetic ester.The optimum ratio of synthetic ester and mineral oil for enhanced performance was found as 1:4 for both fresh and aged mineral oils.This adds an advantage of reduced synthetic ester requirement and, thus, reduced cost.
A comparison of results also revealed that the optimum ratio of mineral oil and synthetic ester depends on the ageing condition of the oil, electrical, physiochemical, and daddario ej10 thermal properties of the blended oil.The results also proved that the aged mineral oil can be reused after blending it with synthetic ester, which avoids discarding the oil.