Progress in outdoor insulation research in China

A summary is presented of studies on outdoor insulation in China. Past investigations of the characteristics of outdoor insulation are described. Due to the special features of Chinese topography and the increasing severity of pollution as a result of the development of industry in China, a series of studies was made to understand the influence of atmospheric parameters-air density, humidity, and temperature-on the dielectric strength of outdoor insulation. The influence of a few factors on flashover, such as the flashover criteria for contaminated insulators, the role of local arc with respect to the pollution performance of insulators, and the pollution discharge at low pressure, are discussed. >