Flashover arc motion and its effects on spacer-surface damage in gas-insulated systems

Breakdown or flashover arcs in gas insulated systems (GIS) produce a magnetic force which influences the path of the arc and has a decisive effect on the spacer-surface damage experienced during flashovers. An experimental arrangement was developed to study breakdown/ flashover arc dynamics and their effect on spacer-surface damage in an 8 m experimental GIS. A mild-steel flange and aluminium disc piece were made to hold the test epoxy resin spacer and to have an access to take arc photographs in an open-to-air configuration at the open end of the GIS, with special spacer-electrode arrangements to study the arc lift off and push onto the surface during flashover on both sides of the spacer. The principle of arc dynamics is discussed, along with, experimental arrangements, results obtained from arc photographs and the effects of the arc path on spacer-surface damage