Shu Lichun

DC flashover performance of iced insulators under pressure and pollution conditions

In an artificial climate chamber, DC flashover tests of insulator strings were performed under various ice, pressure, and pollution conditions. Based on these results, curves for the relationship between the DC flashover voltage of the insulator string and the pressure, the ice weight, and the pollution degree are given and analyzed. It is shown that, under the same ice weight and the same pressure, the DC flashover voltage of the precontaminated iced insulators is lower than that of clean insulators. The larger the pollution degree, the lower is the flashover voltage. Under the same pollution degree and the same pressure, the DC flashover voltage of the precontaminated iced insulators decreases as the atmospheric pressure decreases.<<ETX>>

AC flashover performance and voltage correction of 27.5 and 110 kV iced composite insulator at 4000/spl sim/5500 m high altitude districts

Based on the test results carried out in the multi-function artificial climate chamber of Chongqing University (China) on two types of composite insulator, this paper discusses the effects of atmospheric pressures or altitudes, contamination level and ice amount secreted on the minimum AC flashover voltages of composite insulators, and analyzes the flashover performance of the composite insulator in icing, contaminating and low pressure conditions. The authors therefore put forward a correction method of flashover voltages.