Novel geometry in low-voltage circuit breakers

Abstract

The simulation and analysis of the complex phenomenon of an electric arc propagation in low voltage chambers was investigated. The objective was to compare the effect of different geometries in the time required to achieve the extinction of the electric arc. The analysis is performed by electromagnetic field phenomena numerical simulations coupled with computational fluid dynamics and energy transfer. The aim is to propose a novel geometry that will improve the functioning of the electric arc propagation and extinction. The chamber consists of two electrodes of materials iron (cathode) and aluminium (anode), splitter plates of iron, and a fluid domain of air. The electric arc is modelled as a plasma column of 100 A of DC (Direct Current) flowing through air initially at 1 × 104 K, and atmospheric conditions for the fluid domain. Temperature-dependent properties are considered in the model. The simulations are performed by changing the configuration of geometric parameters in the proposed model and comparing the surface force along the plasma column. Once the geometries that exert a higher force were selected, a multiphysics transient simulation of the movement of the arc was performed and the extinction time was noted. A 13% of improvement in the extinction time was obtained in a geometry with lower displaced splitter plates occupying the same space, without the need to add any extra materials or extra costs to the original design.