The Distinguishing Quality of Water Droplets on Insulating Surface under AC and DC Electric Field Stress

Abstract

This paper presents the comparison of water droplets on insulating surface under alternating current (AC) and direct current (DC) electric field. Besides that, it is demonstrated about the insulator deterioration under both electric field stressed due to an ageing and partial discharge (PD) phenomenon. The vital parameters factors are water droplets conductivity, droplet volume, surface roughness and droplet positioning that they cause to occur the electric field intensification. The field is intensified at the interface between the droplet, air and insulating material. Thus, the PD occurred due to electric field intensification increases with the deformed droplet. The deformation of water droplet under AC electric field stress is more intense than DC field. The electrostatic forces change the droplet shapes and spread them along the electric field direction. The local electric field intensification provokes the PD giving way to reduction of hydrophobicity of insulator surfaces. In addition, the PD activity could appear as a trigger for a surface breakdown. And the localized arcs cause damage to insulating material then finally leads to deterioration of insulation materials and the pollutant contamination.