Study On Influence Analysis And Treatment Plan Of EAF On Power Quality Of Power Grid

The steel industry has always been the lifeblood of the national economy.Since the 13 th Five-Year Plan,the state has paid more attention to environmental protection and has required the complete elimination of steel-making equipment with low energy efficiency and high pollution.It has also promoted the rapid development of electric arc furnaces in the direction of large capacity and high power.However,as a typical impact load,the power quality problem caused by the large-capacity electric arc furnace connected to the grid is very serious.Therefore,based on the analysis of power quality problems in electric arc furnace system,the research on harmonic and reactive power compensation on grid side has important social environmental significance and academic value.This paper firstly gived a brief introduction to the development of electric arc furnace,process flow,electrical equipment,and electrical characteristics.Then,with 80 tons of electric arc furnace as the research background,the data of the power supply equipment and the electric arc furnace production line were collected,and the electric energy quality test of the electric arc furnace production line before the treatment was carried out.The test data was carried out according to relevant national standards and test results were given.A nonlinear time-varying resistance model of the arc is established,and power qulity of the electric arc furnace was analyzed in combination with the electrical system model.The comparison between the simulated data and the measured data showed that the established arc model can truly reflect the harmonic characteristics and voltage fluctuations and flicker problems of the arc furnace.The three-phase arc coupling law was analyzed by changing the input of one phase arc length.Simulation showed the characteristics of the arc voltage and current during the melting period and refining period by adjusting the three-phase arc length.The reactive current detection method and control strategy of common load were introduced.Based on this,the positive and negative double-sequence current inner loop decoupling control strategy for electric arc furnace load was proposed.The SVG simulation model is established by triangular wave comparison method.The SVG was used to compensate the balanced load and the unbalanced load.The voltage and current in compensated system were basically in phase,and the power factor was improved,which verified the effectiveness of the SVG model.In order to improve the power quality problem caused by electric arc furnace,this paper proposed SVG+FC comprehensive compensation scheme.Firstly,we verified the effectiveness of the scheme by simulation.Then we showed governance effect by the power quality test results when the actual equipment has been put into operation.