Surface flashover characteristics of Mylar in compressed SF6

The surface flashover characteristics of solid dielectric barriers in a rod-plane configuration have been investigated in compressed SF6 at pressures up to 600 kPa for 60 Hz voltages, lightning and switching impulse voltages in order to determine the effect of the radius of curvature of the highest stressed electrode. The effect of a thin epoxy coating on the rod electrode was also investigated and found to give significant increases in the 60 Hz corona onset voltage at the higher pressures of SF6 and in the breakdown voltage for all gas pressures and voltages shapes. This work is part of a research program supported by the U. S. Department of Energy.