Some Properties of Solid-Liquid Composite Dielectric Systems

The phenomenological aspects of the electrical properties of Solid-liquid dielectrics are discussed with special relevance to the utilization of such systems at high electric stresses. The implications of conduction, dielectric loss and breakdown in the separate phases have been related to the performance of the solid-liquid system as a whole. The effects of solid dielectric structure and thickness have been developed and associated with possible breakdown processes for the impregnated dielectric in practical situations. The use of plastic films, with or without paper, in impregnated capacitors is treated at some length as a useful device for developing the criteria which are important in all highly stressed solid-liquid systems. Considerable attention is given to aging phenomena and the way in which they may lead to various forms of failure in impregnated systems. Comprehensive data are provided from a summary of the literature relating to effects of temperature and electric stress applied singly and in combination. The effects of life-prolonging additives have been discussed briefly.