1998 Volume 118 Issue 1 Pages 77-84
The effect of particles' shape on partial discharge inception electric field was investigated in oil immersed insulating system. Particles' shape effect can be evaluated by shape- parameter for copper particles. Various particles were evaluated in material, size and density on partial discharge inception electric field. The metallic particle causes the initiation voltage of partial discharge to be lower than the dielectric particles. However the property can be deteriorated by dense dielectric particles remarkably. The motion of dense dielectric particles was observed with high speed camera at the instance of partial discharge initiation. It is found that partial discharge depends on the motion of particles rather than the bridge formation of particles across the gap. Positively charged particle arrives at pressboard on negative electrode to cause partial discharge.