Modeling of ac arc furnace and its influence on the relay protection

This paper presents a novel model of the electric arc furnace (EAF) based on energy conservation theory. Starting from the arc energy balancing equation for the electric arc, the proposed model is able to reflect the steady-state operating characteristic of arc furnace accurately. Then the dynamic arc furnace model can be obtained by modulating the definitive model with white noises. The model is proved to be accurate and valid tested by simulation. Due to the adverse effects produced by the operation of arc furnace, it also analyzes the influence on the protective relay, which includes: the mal-operation of negative sequence relay and frequent operation of startup component. The suppressing measures with reasonable results for these problems are also presented in this paper.