Pressurized SF6 mixture as the insulating medium for high power system components

High pressure gas mixtures have been used for a number of years as the dielectric media for selected high voltage systems and components. Typical applications range from the Van de Graaff high voltage electrostatic generator to transformers, bushings and circuit breakers. The principal advantages of this medium as compared to liquid and solid dielectrics are that it is flexible in that the breakdown, field strength and total voltage characteristics of any electrode configuration can be varied simply by varying the gas mixture and pressure. An added and probably more important advantage, however, is its recovery characteristic after electrical breakdown and passage of high energy. Thus, gas gaps completely recover, usually within microseconds whereas liquid and solid gaps maintain a conducting path which can be removed normally only by recirculating and cleaning the liquid or replacing the solid.