Streaming Electrification Characteristics of Silicone Oil

We present a study of the performance of silicone oil as an environmentally friendly and flame retardant insulating medium for electric power equipment. We have investigated the streaming electrification characteristics for flowing silicone oil for cooling of electric power equipment. As the initial step, the electric charge density accumulated in silicone oil and on the surface of the insulator is investigated simultaneously. We have used 5 types of insulating material for the experiment, including aramid paper. Silicone oil becomes negatively charged by streaming electrification, in contrast to conventional mineral oil, and the magnitude of the electric charge density on the insulating material is influenced by the kind of insulating material. As the second step, the streaming electrification characteristics of silicone oil were further examined using an insulator for which the work function is known. Based on these results, streaming electrification for various kinds of insulator and silicone oil is evaluated with respect to the work function. We consider the optimum combination of silicone oil and insulating material.