Modeling the Arc Splitting Process in Low-Voltage Arc Chutes

Abstract

Investigations on the arc splitting process in low- voltage arc chutes have shown that a threshold voltage has to be exceeded before new arc roots form. When an arc spot has been formed, the electrode fall is nearly constant and rather independent of the current. In simulations a thin layer of elements with a nonlinear current density-voltage characteristic surrounding the splitter plate represents the formation of new arc roots. To model this behavior a characteristic with a voltage hump at low current densities and a constant final voltage at higher current densities has been presented in former publications. In this paper, the influence of the magnitude of the voltage hump is studied. A lower voltage hump yields a smaller arc loop around the front edge of the splitter plate and an earlier subdivision of the arc. A too high voltage hump makes arc splitting impossible. A comparing simulation without any arc root model, but only with the properties of the metallic plates, shows that a realistic simulation of the arc splitting process needs special treatment of the arc roots. The results are compared and verified on the basis of experimental results. Hence, the arc splitting process is analyzed concerning arc voltage and current through the plate as well as location of the arc roots.