Anomalous creeping flashover characteristics in N/sub 2//SF/sub 6/ mixed gas under single pulse voltage

Creeping flashover characteristics for the needle electrode-plane electrode filled with N/sub 2//SF/sub 6/ gas mixtures have been investigated. In the case of the needle-plane configuration, the flashover voltage was enhanced by an admixture of SF/sub 6/ into N/sub 2/. On the other hand, by the insertion of a solid dielectric barrier between the needle and the plane, only the negative creeping flashover voltage was reduced drastically by the admixture of SF/sub 6/ gas into N/sub 2/ gas, and a highly emissive region at the top of a creeping corona was found in N/sub 2//SF/sub 6/ gas mixture. This behavior is strongly affected by the creeping corona extension process, depending on the creeping distance and the gas pressure.