Voltage flicker analysis and mitigation - case study in ac electric arc furnace using PSCAD/EMTDC

Voltage flicker, a phenomenon of light intensity fluctuation is caused by large and rapid industrial load changes. The ac electric arc furnace is one of the major sources generating voltage fluctuations, deteriorating the power quality. In the present work, the voltage fluctuations produced by a 4 tone ac EAF and its effect on the 11 kV/0.566 kV distribution system is analyzed. The EAF load is modeled based on field measurement data obtained from the ac EAF at a modern steel manufacturing plant, Chennai, Tamil Nadu, India. Voltage flicker mitigation studies are carried out with and without static var compensator. Controlling the firing angle of the SVC eliminates the low frequency voltage oscillations due to EAF load currents in the distribution system. The PSCAD/EMTDC software is used for modeling and simulation and the results are presented.