Progress in Vacuum Flashover Mechanism: Validity of ETPR Theory

In this paper, the literature on vacuum flashover and mechanisms are reviewed, and the development of the Electron triggered polarization relaxation (ETPR) theory is the main content. New evidence is provided to prove the validity of the ETPR theory. Polymer composites show sine-variations in vacuum flashover with the filler content increase is a substantial supporting for ETPR theory. The trap depth and polarization variations corresponding to the transitions of the topological relationship of fillers in the polymer matrix are considered to be the leading causes of the regular variations of flashover. An experiment of grain ejection is designed to verify the application of ETPR. The findings can provide a better understanding of the essential role of dielectric on the flashover, which also supplies a base for surface insulation on the gas atmosphere.