Computational Study of Plasma Flow in Arcing Horns During a Voltage Surge

Arcing horns are used to protect insulators from high-electric stress conditions. These horns maintain a certain gap between the horn tip such that under excess voltage or current conditions, the air between the horn breaks down prior to any flashover event across the bushing. Prior to the breakdown, a conductive plasma channel forms between the arcing horns. This are formation leads to a parallel current path that prevents high voltage build up across the insulator. In this study, we use VizSpark, a high-fidelity coupled thermal plasma flow simulator, to understand arcing phenomena in are horns in an over voltage condition. The horn geometry corresponds to DIN 42351. It is demonstrated that the initial voltage surge is followed by the gap voltage of
$\sim$
l kV that is sustained during the arcing process. Restrike events are captured in the simulation that corresponds to step change in the instantaneous arc power. The peak power of the arc is observed to be 250 kW.