Study on Partial Discharge with Water Droplets on the Circular Epoxy Resin Insulator under AC Electric Field Stress

Abstract

The partial discharge on the insulator surfaces usually occurred in the distribution system. The influence of water droplets is investigated in this paper. This experiment used a circular resin specimen under High Voltage Alternating Current (HVAC) field stress that was applied to the electrodes with a diameter of 2 mm and with a distance between both electrodes of 35 mm. For this methodology, both a single droplet and also double droplets were used on surfaces and the voltage level was adjusted by 15 kV. Results showed that, firstly, the corona phenomenon occurred around the circular electrode after the water droplets on the specimen surface were stretched to each other, but the double drops took a lower voltage level for the stretching than the single drop. In addition, the double drops acted as a bridge, allowing an electrical field to be generated from both electrodes. This pulled them, easily resulting in arcing. In conclusion, water droplets are a main factor to the aging that occurred on the insulators surfaces and this effect is presented in this experiment.