The influence of a conducting particle on a spacer on the insulation properties in SF/sub 6//N/sub 2/ mixtures

The flashover behaviour of a spacer sample with a conducting particle on the surface was investigated for several SF 6 /N 2 mixtures with SF 6 content up to 30 %. LI 1.2/50 μs and AC 50 Hz were used to stress the setup. The gas pressure ranged from 100 to 600 kPa. The particle was 0.25 mm in diameter with a length of 2 to 8.5 mm. The spacer sample was 25 mn in diameter and 45 mm in length and made out of epoxy resin filled with Al 2 O 3 . The results of the investigations show the influence of the particle length and the gas pressure on the flashover voltage for various SF 6 contents of the mixtures.