Effect of air pressure on the characteristics of AC partial arcs over the polluted insulation surface

Flashover of contaminated insulators is one of the major problems for the power distribution, especially in high altitude area. Laboratory experiments have shown that low pressure have great influences on the flashover performance of outdoor insulators. In order to investigate the influence of low pressure on the characteristics of AC partial arc, an experimental system was designed in this paper. The V-I characteristics of AC partial arc under different air pressure were obtained by adding a measuring electrode over the polluted insulation surface. And the fitting formulas between arc constant A, n and gas pressure was given based on the obtained experimental data. It can be concluded that the arc constant parameter n stayed the same when the air pressure changed. While, the parameter A increased with the increasing air pressure. This work can enrich the investigation of the mechanism of arc propagation and calculation model of insulator flashover voltage.