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 m agnetic 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 ar c dynamics and their effect on spacer-surface damage in an 8 m experim ental GIS. A mild-steel flange and aluminium disc piece were made to h old the test epoxy-resin spacer and to have an access to take arc phot ographs in an open-to-air configuration at the open end of the GIS, wi th special spacer-electrode arrangements to study the arc lift off and push onto the surface during flashover on both sides of the spacer. T he principle of arc dynamics is discussed, along with, experimental ar rangements, results obtained from arc photographs and the effects of t he arc path on spacer-surface damage.