Leakage current characteristics of polluted insulators at high altitudes

The discharge performance of air-gap and insulator string at high altitude regions is different from that of the referring standard conditions as the relative air density decreases with the increasing of altitude. This difference is one of the key question in engineering design of the external insulation. Since the leakage currents of contaminated insulators comprised a large number of noises before partial discharging, it was very difficult to obtain the valid characteristics of signals, especially under high altitude. For the purpose of obtaining surface discharge voltage and its correction in different altitudes, typical proclaim insulator was selected, and comparative experiments were conducted under different altitudes from 0m to 4000m in environmental climate laboratory. The leakage currents of porcelain is monitored and analyzed in various pollution conditions. The results are useful for the pre-warning of the contamination flashover under high altitude conditions. This study provide essential technical support for designing outdoor insulators of power systems in high-altitude regions.