Nanosecond streak photography of discharge initiation on ice surfaces

This paper presents an exploratory experimental study of discharge initiation on surface of ice. The phenomena underlying these processes are, as yet, poorly understood. To elucidate the initiation process in particular, ultra high-speed streak photography was used to observe and analyze the first visible discharges and a number of parameters were investigated. It could be shown that ambient temperature, conductivity of ice surface and the presence of imperfections on the ice surface influence not only the critical voltage for discharge initiation, but also the velocity of discharge development. Some parameters could be identified, which should be investigated further. The present paper is the first stage of a long-term research effort in this new field. This study should enable further experimental investigations and mathematical simulations to gain better understanding of ice surface discharges, specifically in the context of electrical insulation integrity of support insulators in power systems operating under severe atmospheric conditions.