The relevance between dramatic declines of air gap breakdown voltage and fog-haze weather

The severe air pollution and fog-haze weather occurred frequently in China recent years. It is necessary to study the effect of special weather on the discharge characteristic of external insulation. In this paper, automatic discharge monitoring systems are installed in Guangzhou, a Chinese economic center and haze center, to monitor the breakdown voltage of an air gap and atmospheric parameters (such as relative humidity etc.). The research shows that the probability of dramatic declines of air gap breakdown voltage (DDAGBV) during the fog-haze weather is far more than the whole year´s, but under haze weather it much lower than the average. Combined the discharge voltage and weather parameter monitored with air quality data published by Guangzhou City Bureau of Meteorology, the reason of DDAGBV under fog-haze weather is studied. Analysis shows that the DDAGBV mainly occur under the condition of higher humidity, air quality index less than 120 (air quality is excellent, good and slight pollution). Based on the comprehensive analysis, the paper put forward that the electric field distortion rather than air pollution is the main reason of DDAGBV under the fog-haze weather.