| There are often reports on flashover accidents caused by ice adhesion of the insulators, and the reason is that the insulation performance of the iced insulators decreased apparently. While with the development of the EHV(extra high voltage) and UHV(ultra high voltage) power transmission, it is sometimes inevitable for the corridor and substations to cross the iced, contamination and high altitude areas, which are complex in environment, thus, research on the flashover property of the EHV(extra high voltage) and UHV(ultra high voltage) iced insulators is of great theoretical and engineering application meaning.Based on the research of foreign and domestic scholars,1000kV post insulator and500kV bushing flashover characteristic test is done in artificial climate test laboratory of UHV AC test base of SGCC. The following work is done in the dissertation:the ice flashover voltage of the post insulators has close relationship with the conductivity of the iced water, and the ESDD etc; analyze of the influence of energized icing to the ice condition of the post insulators; analyze of the flashover process of the post insulators in the substations; the influence of contamination degree to the flashover voltage of the post insulator. The ice flashover model is proposed, with which the flashover voltage is verified. The test result shows that under heavy ice adhesion no matter the ESDD,1000kV post insulator and500kV bushing flashover voltage is lower than rated voltage roughly10-30%.500kV bushing’s gradient of ice flashover voltage is lower than500kV post insulator, but higher than1OOOkV post insulator. The ice flashover model predictions and experimental results compared to the mean error of less than8%, the accuracy of the model prediction is guaranteed. Obenaus flashover model is used for EHV and UHV post insulator’s flashover voltage prediction is feasible. The research results can be a reference for EHV/UHV post insulator’s configuration and the flashover voltage’s prediction. |
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