The method of dynamic volt-ampere characteristics is described. The influence of the constant component of the electrode current on the resistances estimating accuracy for different furnace zones and the current and voltage constant components of the arc is noted. The improved algorithm for determining these parameters and results of its testing in a laboratory experiment with charge metallized additive for steel smelting are presented. It is shown that the scale addition does not have a negative effect on the process, but, on the contrary, causes a slight decrease in the value of the constant component of the arc and promotes the slag foaming.