Dynamic Moisture of Energized Insulator Contamination Layers with Humidity Variation

Pollution flashover is a major accident affecting the safety of the power system and contamination is the premise of flashover. Monitoring the insulator pollution degree in an environment with low air humidity is very important for system maintenance. Winter is the general period for insulator contamination because the weather tends to be dry with less rain, but the insulator flashover generally happens in the spring or summer when its surface pollution is heavy, and the weather is wet. The traditional leakage-current-based insulator monitoring system can only detect and send the flashover warning signal when the weather is humid, which means It may only leave only a few minutes and is too late for line maintenance. To this end, the wetting of the contaminated insulator surface at non-100% relative humidity was studied in this paper. It was found that with the change of surrounding humidity, due to both effects of moisture absorption and evaporation, the water absorption of the contamination layer changed with an exponential approach function. The research results can provide some references for the future insulator contamination monitoring system.