Effects due to metallic particle contaminations in SF6/N2 Gas Insulated Busduct

Sulphur Hexafluoride is an insulating and switching gas found for the development of metal clad high voltage substations in the year 1960s. Since SF₆ has found to be a green house gas contributing to the global warming of the atmosphere and also highly toxic and corrosive components are formed when SF₆ is subjected to an electric discharge. 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) are due to the existence of various metallic contaminations in the form of loose particles. Diluted SF₆/N₂ mixtures could be a substitute to pure SF₆ as insulation medium for high voltage gas insulated systems. They promise to have a lower environmental impact than a system insulated with pure SF₆ for the same rating. The main issue concerning the practical use of such mixtures is their behavior in the presence of particle contamination. In this paper, particle movement is determined in Gas Insulated Busduct (GIB) with Sulphur Hexafluoride and Nitrogen gas mixtures as insulating medium. In the gas mixture, conducting particle material considered for this study are Aluminium and Copper.