Mathematical model for the harmonic analysis of electric arc currents and voltages in an electric arc furnace

This paper analyzes how the relative effective total odd and even current and voltage harmonics of an electric arc in a furnace correlate with the thermal time constant of the arc, with the valve effect, and with the asymmetrical operation. The furnace circuit model was used to theorize upon the effectiveness of using even harmonics data to diagnose the charge melting stage during initial melting; and odd harmonics to analyze the late stages. The results of mathematical modeling helped draw guidelines for the design of the charge melting diagnosis unit to be part of the electrical parameters control system; the unit design depends on the furnace type. The results could be of use in research of better control algorithms for electric arc furnaces and lade furnaces with a focus on reducing the energy costs of producing molten steel.