Analysis of the accident based on low temperature, snowstorm, ice, coagulation

When the diameter of ice covering lines is over 40-60 mm (Hunan) or even 300 mm (Guizhou), much bigger than the standard line parameter of 15-30 mm, it will lead to the collapse of towers of 220 KV/500 KV transmission systems. The paper summarizes the accidence occurred in China at the beginning of 2008 and presents optimal design philosophy for the transmission line of EHV/UHV.