Özet:

Recent repeated flashovers and power outage incidents in an (400/132) kV substation, located in the Ad Diwaniyah Province, have called for extensive investigations to evaluate the effect of subsequent deposition of sandstorm and free carbon particles (soot) on the performance of HV insulators and probable flashover occurrences. In the Ad Diwaniyah Province, the insulators of the transmission lines and substations are normally subjected to sandstorms (once or twice per year). Moreover, rapid brick industry expansion (10 brick factories constructed and operated over the last ten years) within the area of the Shafeyea, where, the (400/132) kV substation is located, has also led to a noticeable industrial pollution. Porcelain and polymeric insulators were exposed to sand and soot polluted environments and the effect of pollution severity on the flashover characteristics was investigated. Flashover voltages were measured under various simulated polluted environments for both porcelain and polymeric insulators. Obtained results show that the deposition rate of soot particles is highly increased when both porcelain and polymeric insulators are already polluted with sand particles regardless of whether the sand particles are charged or not. However, moistening was found very critical to pollutant layer build-up and consequently increases the severity of pollution.

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