Investigation of breakdown characteristics of N2, SF6 and SF6-N2 mixtures under pressure

Breakdown behaviour of a rod-plane gap and a plane-plane gap is investigated for N₂ and N₂-SF₆ mixtures for pressure up to 8 bar. In N₂, results show the role of the nonuniformity of the applied electrical field on U₅₀ breakdown voltage values in both polarities. Average values of reduced breakdown field associated to the guiding fields of negative streamer are measured versus the pressure in N₂. The effects of surface roughness on U₅₀ are pointed out. The critical reduced field versus pressure for N₂, SF₆ and different mixtures is measured