Flashover performance of ice-covered insulators

The presence of ice on the surface of insulators is sometimes the cause of severe problems in power networks. In fact, the presence of ice reduces the electrical performance of insulators in ways that can, in some circumstances, lead to flashover, resulting in power outages. The maximum withstand voltage of ice-covered insulators is distinctly inferior to that of clean insulators. The electrical performance of insulators also depends on atmospheric conditions during the formation and development of ice deposits. Temperature liquid water content, wind speed, water droplet size, conductivity of precipitation, as well as the nature and strength of the electric field are major factors influencing the type, quantity and uniformity of ice. This paper gives an account of the research carried out on the electrical behaviour of ice-covered insulators, particularly in relation to laboratory ice simulation, voltage application methods and the major intervening factors. The paper also reports on the work being done in laboratories around the world, and highlights the results obtained at the High Voltage and Atmospheric Icing Laboratory of the University of Quebec in Chicoutimi (UQAC).