Mitigation of voltage fluctuation for an industrial customer with arc furnace

This paper investigates the voltage fluctuation problem of a large steel plant in Taiwan and presents the mitigation strategy by applying the static VAr compensator (SVC) and cogenerator. The fluctuation of real power and reactive power consumption by an arc furnace has been measured and recorded during the steel production process. The dynamic load model of the AC arc furnace is derived and simulated in the CYME software package for load flow analysis. The block diagrams of SVC controller and the excitation system of the cogenerator are included in the computer simulation to solve the response of reactive power compensation according to the voltage fluctuation of the control bus. To maintain the electric service reliability of the arc furnace when an external utility fault occurs, the tie line tripping and load shedding is implemented to prevent the tripping of the cogenerator after system disturbance. It is found that the dynamic load behavior of the arc furnace in the isolated industrial power system can be well compensated by the cogenerator with adaptive control of exciter and governor to generate proper reactive power and real power according to the fluctuation of bus voltage and system frequency respectively.