Study On AC Flashover Performance And Preventive Measures Of Iced Post Insulators

There are much investigations of icing flashover performance of line suspension insulators while there a few ones of substation post insulators. Under the same icing conditions, the sheds of post insulators are more easily bridged by icicles because of their configuration compared with those of suspension insulators, which results in that the icing flashover voltages of post insulators decrease obviously. There are many icing flashover accidents in the Southern of China in 2008. With the exploitation of abundant electric resource, the icing of post insulators will be one of key factors restricting the construction of UHV electric network. Therefore, the study on AC flashover performance and preventive measures of iced post insulators is of important significance.Based on the present investigations in China as well as other countries, a great of tests and analyses of iced 110kV post insulators have been carried out in a large multi-function artificial climate chamber, as well as the iced post insulators equipped with RTV sheds have been conducted in the thesis.In the paper,the conclusion of the flashover voltages of iced post insulators are affected by salt deposit density, freezing-water conductivity, icing quantity and density of ice was bing up according to the result of experiment, The relationship between the minimum icing flashover voltage of post insulator and influence factor are introduced.There are difference among the icing flashover voltages for the post insulators with various shed shapes. Under the light icing conditions, the post insulators with the large-and-small sheds have higher icing flashover voltages than those with the equal-diameter sheds. But after the sheds are bridged by icicles, there are small difference among the icing flashover voltages because the the partial arc develops along the icicles.The result of experimentation in this paper make clear that RTV sheds will restric the bridging of icicles and the partial arc develops along the insulator surface, which can availably improve the icing flashover voltages. But PRTV paint have not obvious effect to improve the icing flashover voltage of post insulator...