Effect of temperature oh high field conduction current in service aged transformer oil

The research work that has been carried out regarding the electrical conductivity of dielectric liquids, under various experimental conditions for industrial purposes or for physical investigations of fundamental character, has not yet been able to explain fully the conduction phenomenon. This is because the problem of conductivity in high fields is quite complicated. Although a considerable amount of work has been done on pure liquids [1] yet little investigation has been made from practical point of view. Particularly no reference is available, as far as the authors knowledge is concerned, as to the conduction behavior of in service aged transformer oil at service elevated temperatures.