Experimental Research Of Electrical Insulating Characteristics About SF₆,N₂ And Their Mixtures

As an excellent electrical insulating dielectric, SF₆ has been widely applied to the power fields. However, it is listed one of the six green house gases by the International Environmental Protection Organization, so that discovering new kinds of the insulating gases and insteading the SF₆ possess greatly theoretical values and practical significance.Having summarized development and application history of the SF₆, it is expounded particularly that show performances of the physics, chemistry, insulation and essence laws of the discharge process, including the Fixed value model and Stochastic model of the electron avalanche processes, conditions of self-sustaining discharge, the physical courses and phenomena of the streamer appeared, evolved and up to breakdown, meanwhile, the mathematical representing are also involved.In the light of practical operation conditions of the SF₆ being utilized in the power system, the experimental model are made up for simulating the uniform, quasi-uniform and nonuniform electric fields, respectively, so that the breakdown characteristics of the SF₆,N₂ and F6/N₂ mixtures are demonstrated to which the 50 Hz and impulse voltages applied under the different compressions and partial pressure ratios.Experiment results are shown as follow:The uniformity of the electric fields applied on the experimental model system insulating with the single N₂ gas has greatly affect to the insulation breakdown, however, the effect of compressive stress is not prominent, and for the single SF₆ as an insulating media, uniformity has important effect on the dielectric strength, and with the gas compression increasing, the breakdown voltages trend to be falling, and for the SF₆/N₂ mixtures, the effect is very...