| With the use of various non-linear electric loads,China's power grid structure is becoming more and more complex,and the phenomenon of multiple power quality problems appearing simultaneously in the same distribution network or power load is gradually increasing,bringing a great deal to users in the power grid influences.At present,the main way to solve this problem is to use different types of power quality devices to manage the corresponding power quality problems.However,multiple power quality problems are commonly encountered in the power grid,it is usually necessary to use a variety of power quality management devices to regulate the corresponding power quality.However,the lack of relatively uniform technical standards between various power quality devices increases the difficulty of coordination between devices and also increases the total cost of equipment.The Unified Power Quality Conditioner(UPQC)can effectively handle power quality problems in the power grid,such as voltage drops,three-phase unbalance,and current distortion caused by harmonics.However,in recent years,the Zhenjiang area distribution network studied in this paper has caused a large number of non-linear loads,resulting in frequent voltage drop and harmonic problems.For this reason,the power quality of the distribution network will be treated by UPQC.In this paper,the power requirements of different loads in the 10 kV distribution network in the development zone are studied.Based on this,the current 10 kV voltage qualification rate and harmonic distribution are analyzed.Secondly,the basic structure of UPQC and The working principle is analyzed.By comparing the voltage type and current type structure commonly used by UPQC,the voltage type structure with better performance is selected,and the control algorithm of the series link and parallel link of UPQC is designed.Then,the control strategy of UPQC is designed.Through the design of the voltage on the series side and the current control strategy of the parallel side,the basic control of the converter operation is completed,and the PID control strategy adopted in the DC side link is insufficient.The LADRC control strategy is adopted to improve the accuracy of the DC side voltage control,and MATLAB simulation is used to verify whether the designed control strategy is effective.Finally,the experimental platform of UPQC was built.The device designed by the experimental analysis can effectively control the power quality.After confirming that the designed system can effectively control the power quality,it will be put into operation and the results of data analysis after commissioning are used to verify the effectiveness of the designed device for power quality management. |
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