Improved Dielectric Strength of SF6 Gas with a Trichlorotrifluoroethane Vapor Additive

This paper presents a new approach to improvement in the dielectric strength of SF6 gas insulation. Experiments show that the addition of a small amount of trichlorotriflouroethane (R113) vapor cannot only increase the breakdown voltages within the corona stabilization region, but also improve corona onset voltages of SF6 in highly nonuniform field gaps. This additive is found superior to those used by other investigators in improving corona stabilization. Experimental results also show that the explanation of the effect of additives on corona stabilization suggested hitherto, should be reconsidered.