Dielectric Losses in Solid-Liquid Insulating Systems - Part I

A comparative study has been carried out on the dielectric-loss behavior of kraft-paper cable models impregnated with standard insulating oils and silicone liquids of the same viscosity range. It has been found that the ionic conduction losses in the solid-liquid systems are more affected by the viscosity than the chemical structure of the impregnant. Cable models impregnated with the low-viscosity silicone impregnant exhibited appreciable contamination effects; however, the associated space-charge-loss mechanism with these models caused the overall dielectric-loss magnitude to diminish over an appreciable range of field strengths. This was not found to be the case with the high-viscosity oil and silicone impregnants.