Dynamic Measurement of Surface Discharge under Different Gaseous Environments and Pressures

This paper is concerned with the application of the Pockels technique for measuring high voltage surface discharge under local conditions similar to those found in practical gas-insulated-switchgear. A 160 mum thick bismuth silicon oxide (BSO) crystal was utilized as the sensor to quantify charge distribution generated from a needle electrode under two cycles of AC voltage. Results obtained from using SF₆, N₂ and their mixtures as an insulating gas are compared with those of air. The effects of gas pressure on discharge behavior are also investigated and discussed with reference to the availability of initiatory electrons, the electron mean free path and Paschen´s curve.