Highlighting Capacitive Phenomena in the Discharges Propagation on the Insulators Surface Immersed in Fluids

The aim of this article is to highlight the involvement of capacitive phenomena in the mechanisms of discharge propagation on the insulators immersed in fluid, in the presence of a divergent electric field, under different types of voltages. Insulators issued from different materials and different fluids (liquids and gases) are investigated. The role of the relative dielectric permittivities (dielectric constants) of both constituents of the interface and the thickness of the insulator in the propagation mechanisms is demonstrated. The length of radial discharges and the number of their branches increase when the thickness of the insulator reduces and/or the relative dielectric permittivity of the insulator or that of liquid increases.