PD CHARACTERISTICS OF SF6-N2 (10:90) GAS MIXTURES WITH METALLIC PARTICLES

Conducting particles in a coaxial duct are responsible for a large part of the failures registered in gas insulated systems. Electrical insulation performance of Gas Insulated Systems (GIS) is adversely affected by metallic particle contaminants. These particles get into the system accidentally during GIS assembly and they start vibrating during shipment. As five particles, they move under the action of electric field and then can adhere to the conductor or insulating spacers. These free conducting particles cause high field distortions. These particles produce surface charges due to partial discharge activities. Co-axial duct placed in a high pressure chamber is used for the purpose. This paper deals with the effect of Copper and Nichrome particles introduced inside the co-axial duct on the Partial Discharge characteristics of the co axial duct in SF6-N2 gas mixture in the ratio 10:90 at gas pressures of 0.1MPa. The discharge characteristics as a function of the voltage are discussed in this paper.