Influence of unbalanced voltages on the movement of metallic particle in a three phase common enclosure gas insulated busduct

Abstract

Sulphur Hexafluoride (SF6) is generally found to be very sensitive to field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants. A study of CIGRE group suggests that 20% of failures in Gas Insulated Substations (GIS) is due to the existence of various metallic contaminations in the form of loose particles. The presence of contamination can therefore be a problem with gas-insulated substations operating at high fields. If the effects of these particles could be eliminated, then this would improve the reliability of compressed gas insulated substation. It would also offer the possibility of operating at higher fields to affect a potential reduction in the GIS size with subsequent savings in the cost of manufacture and installation. The purpose of this paper is to develop techniques, which will formulate the basic equations that will govern the movement of metallic particles like aluminum, silver and copper in a bus duct. Simulation is carried out on particle movement with balanced and unbalanced voltages and the results have been presented and analysed.