Experimental studies on the statistical breakdown characteristic of SF6

For insulation co-ordination of large gas insulated switchgear (GIS) and especially for gas-insulated transmission lines (GIL), due to their high enlargement factor, it is very important to have exact knowledge of the breakdown probability distribution function and its parameters. The reasons for using a Weibull distributed breakdown probability are explained and the resulting conclusions for insulation co-ordination are presented. Furthermore investigations were undertaken in pure SF₆ on different electrode arrangements and gas pressures. The test results of a laboratory setup and a complete switching device are presented and discussed with respect to the applicability of the Weibull distribution and the determination of its parameters