Numerical Thermofluid Simulation on 10 kA-class High Current Fault Arcs in Air Contaminated with Metal Vapor from Evaporation of Metal Electrodes in Open Air

Abstract

This paper describes the behavior of an arc discharge in open air contaminated with metallic vapor between cathode and anode for kA-class high current using the numerical model. This simulation is related to a fundamental study on an arc discharge in high energy arcing fault (HEAF), which can be found occasionally in electric equipments like nuclear power plants. In this model, evaporation of metal cathode and anode, and metal vapor contamination to the arcs were taken into account. Using this model, the temperature, the pressure rise and the mass fraction of metal vapor in arc plasmas established between Fe electrodes were calculated for ac current of 15 kApeak in open air. The results show that arc temperature reached to more than 25000 K with 10wt% concentration of Fe vapor from electrodes in 15 kApeak arcs.