Review of high voltage gas breakdown and flashover of insulators in compressed sulfur hexafluoride

Compressed SF₆ gas is the main high-voltage insulation medium in gas insulated equipment. Recent progress in studies of high-voltage breakdown in uniform, quasi-uniform, and nonuniform field systems is described. This includes time lags to breakdown, the effect of particle contamination, and the flashover of insulators. Significant progress has been made in developing models for calculating the breakdown voltage in uniform fields. Nonuniform field streamer and leader models have also been developed and have been applied to particle initiated breakdown. Recommendations are given for future work to clarify the mechanisms and critical parameters, particularly for the flashover of insulators