Investigation of streamer propagation along insulating surfaces

Solid insulation materials are used in high voltage gas-insulated devices for mechanical stability reasons or for the separation of different compartments of the device. While solids have generally higher breakdown strength than gases, the weakest parts are often the solid-gas interfaces of the insulation. This contribution presents first measurements of characteristics of surface flashover in a specially constructed setup. The studied samples are epoxy rods with embedded electrodes, especially designed for localized electrodeless streamer inception and discharge propagation along the surface. The capacitances of the overall system are tuned such that current measurements of the discharge can be performed. In this research we focus on the initial phase of discharge propagation – the formation and development of streamers. The main results are the streamer inception voltage and the evolution of the current shape in nitrogen at different pressures