Partial discharge and breakdown mechanisms in ultra-dilute SF/sub 6//N/sub 2/ gas mixtures

With the goal of reducing SF/sub 6/ gas usage, we investigated partial discharge (PD) and breakdown (BD) mechanisms in ultra-dilute (0 to 1%) SF/sub 6//N/sub 2/ gas mixtures. The experimental results and discussions are given in this paper. In particular, we focused our research on the transition characteristics of the electrical insulation performance with an extremely small amount of SF/sub 6/ content, the PD behavior on the applied voltage, and the relation among prebreakdown streamer, return stroke and BD. Moreover, we discussed the PD and so mechanisms with reference of space charge behavior. From these results, the transition threshold at which the influence of SF/sub 6/ gas on the discharge characteristics began to appear, was clarified to be SF/sub 6/ content k=10 ppm for a total pressure of 0.1 MPa.