Influence of Bouncing Metal Particle on Surface Charge Accumulation of A Real Size Epoxy Insulator under DC Voltage

In order to investigate the influence of bouncing particle on surface charge accumulation on a real size insulator under DC voltage, a coaxial electrode system was designed to allow the test under -30 kV in air. A particle jet was applied to produce different bouncing patterns of linear metal particles during the DC charging process, and the charge distribution was measured by a Kelvin type probe. The results indicated that surface charges were accumulated in shape of speckle and the bouncing particle had a much greater impact on the charge accumulation than the immobile metal particle. The position and polarity of charge speckles were determined by different particle bouncing patterns. It is considered that the competition among the surface, the air and the bulk conductions are affected by the bouncing particles, which leads to different surface charge accumulation behaviors.