Research On The Effect Of Nonlinear Load Of High Energy Consumption On Power Quality And Its Control Measures

With the development of the national economy,a large number of high energy users in promoting,which bring the rapid increase of the power consumption and a large number of power grid power quality problem at the same time.So it is very urgent to analyze and control the power quality of high energy consuming users.In this paper,a case study of Taizhou Casting Co.,Ltd is an example of the power quality problem.Through the research,it is found that the harmonic problem is the most serious.The harmonic current produced by induction heating power composed of electronic rectifier equipment and the nonlinear arc furnace load,the rectification unit is the modern power electronic rectifier equipment.In the rectification process,it will produce a lot of harmonic currents.On the other hand,the nonlinear load arc furnace changes the resistance characteristic quickly,and will produce harmonic currents.The harmonic current have a great effect to the power system stable and safe operation of electrical equipment and power quality.Firstly,this paper introduces the specific index of power quality,and then analyzes the types of nonlinear devices and the power quality problems brought by various nonlinear devices.Through the analysis and comparison,it is found that the harmonic problem is the most serious problem in a series of power quality problems.Then,the simulation models of the two most typical nonlinear loads are constructed by MATLAB,which show that the model can accurately reflect the influence of typical nonlinear loads on power quality.Then,the effect on the power quality of grid new nonlinear load calculation by Taizhou Ship Equipment Casting Co.,Ltd is calculated,and a predictive analysis method for harmonic current,voltage fluctuation,flicker and three-phase unbalance is presented,the prediction results show that the company needs to take corresponding measures to control harmonic potential problems.At last,the working principle and circuit topology of active power filter are introduced,and the commonly used harmonic control methods are studied.Then we have carried on the simulation analysis to the harmonic detection method,after comparing the commonly used control methods,we decided to use the hysteresis control method.On the basis of this,the simulation model of three-phase APF system is built by simulink of MATLAB,and the induction heating load composed of three-phase rectifier bridge and electric arc furnace load are carried out for Taizhou Ship Equipment Casting Co.,which shows feasibility and effectiveness of the proposed harmonic control measures.