A Practical Electric Arc Furnace Model For Flicker Assessment

The main flicker source is the irregularly fluctuating loads, specially the AC electric arc furnace (EAF). The random time-varying and nonlinear behavior of the arc is quite difficult to model analytically. The most EAF models are not feasible for flicker planning studies, that is, industry accepted methods to predict voltage flicker levels have not been fully developed. The pre-assessment of flicker produced by an AC arc furnace is a difficult exercise at the approach that should be taken when assessing a feasibility study for loads which may cause disturbance to the supply waveform. Therefore, the feasibility study considering an adequate arc furnace model may help to reduce the likelihood of facilities modifications after they enter into operation. In this regard, this paper aims to develop a simple and useful AC arc furnace model for flicker assessment during the stage of feasibility analysis. Even though the electric arc has a stochastic behavior, it will be noted it has a standard characteristic. Then, the proposed model, implemented in the Alternative Transients Program, is based on the interharmonic characteristic of a real AC EAF. An example system, considering an actual EAF, is used to validate the proposed model by comparing the short-term index of flicker (\(P_\mathrm{st}\)) from measurement and computer simulation on time-domain.