The effect of a metallic particle near a spacer on flashover phenomena in SF/sub 6/

A study of the flashover mechanism initiated by metallic particles in SF/sub 6/ gas is presented. Using a high-speed Imacon photographic camera, it was established that a metallic particle near the insulator surface plays an important role in flashover development. The influence of the particle on flashover development depends on the pressure of the SF/sub 6/ gas. At atmospheric pressure, the flashover was always initiated at a point on the particle farthest from the nearest electrode. At high pressures, it was found that breakdown develops from the electrode of relative positive polarity in the form of a leader. The velocity of the discharge crossing the gap increases exponentially when the distance between the particle and the insulator surface decreases. >