Abstract
In many high voltage gas-insulated switchgears (GIS), flashover voltage is decreased in case of including conducting particles. In particular, the decrease is very severe, when the particles move to and attach on an insulator in GIS. The reason is that surface flashover voltage is usually lower than gaseous flashover voltage in comparatively high pressurized SF6 gas. Some methods for flashover voltage prediction, one of which was proposed by authors, were already proposed of gaseous flashover. However, concerning the surface flashover, only few methods have been proposed.
In the present paper, the prediction method for gaseous flashover of SF6 gas including conducting particles proposed by authors is extended to the prediction method for the surface flashover with particles attached on an epoxy insulator. The characteristic quantities at particle tip are reformed with two supplementary factors included in order to estimate the phenomena peculiar to the surface flashover. It is revealed through comparison with experimental results that the proposed method is useful to predict the flashover voltage along the epoxy insulator of GIS including particles.
