This paper presents a new technique to characterize electrical arc furnaces through the measurement of electric power, stationary and transient states, and the imbalance of these systems. The nonstationary behavior of the voltage and current signals in electric arc furnaces is considered, and analysis techniques of power quality in the time domain are used. ATPDraw (Electromagnetic Transient Program) was used to validate the characterization of the electric arc furnace, and the simulation results were compared with the measurements taken in a local steel manufacturing facility.