Modelling of a DC arc furnace for optimal integration with the supply system

DC are furnaces have gained increasing favour with steel makers all over the world. DC arc furnaces have advantages over their conventional AC counterparts because of their greater supply-friendly nature. Although DC are furnaces still generate flicker, the stochastic component in their harmonics arc reduced and their demands on the supply network are much more compatible with the supply than that of AC arc furnaces. In spite of the relative advantages, however, the input characteristics of DC furnaces still need to be quantified in order to achieve optimal integration with the supply system. System measurements on a 25 MVA DC arc furnace with its filters are correlated with results obtained by numerical integration, and with that obtained through a frequency-domain analytical model that employs harmonic superposition. The behaviour of induction motors is also investigated in this model, when they are subjected to the voltage distortion produced by a DC furnace.