Study Of Voltage Fluctuation And Flicker Caused By Electric Arc Furnace Suppression Method

Iron and steel enterprises have always been used a lot of electric power, AC electric arcfurnace is an important steel-making equipment, due to its outstanding economic, widely presentin the metals industry. But electric arc furnace consumes a lot of electric power, and have lowpower factor, and its operating characteristic determines it will cause a great impact to powersupply system, and easily lead to voltage fluctuation and flicker of the electric grid. The flickerproblems caused by the electric arc furnace, not only directly affect the economic efficiency,product quality and safety of equipment of the steel company, but also affect the periphery ofcorporate and user using power and lighting. The hazards caused by electric arc furnace ismainly due to irregular and random arc caused the reactive power of the power system volatilitychange. Therefore, reactive power compensation can suppress the voltage fluctuation and flicker.The1970s, many steel companies at home and abroad use the static var compensator for theelectric arc furnace reactive power compensation and obtain a good compensation effect and thesignificant economic benefits. Sharply due to electric arc furnace current changes quickly, SVCresponse speed is relatively slow, and compensation devices response speed directly effectvoltage fluctuation and flicker suppression. Therefore, the performance of SVC can no longermeet the increasingly stringent requirements of the power quality. As SVC’s new generationproduct, the static synchronous compensator can quickly and smoothly absorb reactive power,improve power factor, and effectively solute voltage fluctuation and flicker, voltage unbalance,harmonic pollution of power quality problems. But the study for STATCOM focus on thetransmission system reactive power compensation and its control method is current indirectcontrol. The STATCOM used for industrial load compensation in our country is still relativelysmall and the technology is not mature. So this article using STATCOM compensate reactivepower for the electric arc furnace. According to the characteristics of arc furnace load, design aSTATCOM control system based on current direct control with fast response, good trackingperformance.First briefly describe the instantaneous reactive power theory, dynamic reactive powercompensation principle, basic structure of STATCOM, then establish a STATCOM mathematicalmodel for direct current control. Describe the basic working principle and control algorithm ofSTATCOM, usingi p iqmethod assay reactive reference current based on three-phaseinstantaneous reactive power theory; Combining the advantages of Fuzzy control of gooddynamic characteristics, strong robustness and PI control of fast response, no static errors, designfuzzy PI control of STATCOM control algorithm to improve the control accuracy. Finally, usingMATLAB simulation analysis, simulate results show that the STATCOM can rapidly track thereactive power change and demonstrate the rationality and feasibility of the control method.