Metallic particle movement, corona and breakdown in compressed gas insulated transmission line systems

The dynamics of wire particles in a coaxial system under AC voltage is studied using a computational algorithm. An approach for predicting the possibility of SF/sub 6/ gas insulation breakdown due to the presence of metallic contaminants is presented. The technique can be used to evaluate particle trapping effectiveness, during commissioning, of certain designs of metallic particle traps. Also described are some experiments conducted in a 70 mm/190 mm diameter coaxial conductor system in the presence of 0.45 mm diameter, 6.4 mm long aluminum wire particles. It is noted that partial discharges in gas insulated systems are indicative of a potential insulation failure. A major cause of such discharges is the presence of conducting particles in the insulating gas. Corona inception voltage, together with the corona-pulse pattern generated by metallic contaminants, can be used as a diagnostic guide in estimating the size of the conducting particles present in the system.<>