The Optimization Research Of Compensation Performance For Dynamic Voltage Restorer

With the development of economy and technology,the question that many electrical installations are affected by power quality problems becomes more and more serious.On one hand,the equipment is very harsh to the electrical energy quality requirement,on the other hand,their use can pour into the new disturbance for the power grid.Understanding the power quality problem correctly and correcting the power quality problems by the production of high-quality power quality equipment have become an urgent problem which should be solved.In the daily life,the overwhelming majority of power quality problems are the dynamic power quality problems,of which the voltage drop is the most important.The dynamic voltage restorer(DVR)is one of the preferred methods to control the voltage sag,from the economic and technical aspects such as adaptability and comprehensive cost,or the actual application situation at home and abroad.Firstly,the structural analysis of three-phase four-wire DVR for low-voltage distribution network is carrried out,and the design ideas of each unit are clarified.Secondly,The resonant problem of capacitive coupling DVR compensation is discussed.The mechanism of resonance is studied and the resonant problem is solved by adjusting the filter structure,optimizing the control strategy and overvoltage protection.For the DVR system that uses the uncontrolled rectifier to supply power,the harmonic control function is added to eliminate hannonics,without increasing the hardware device.DVR can be achieved by a single power quality control to the direction of diversification of governance.In order to improve the compensation stability of DVR,a compensation strategy of long time compensation is proposed.By setting the phase jump threshold,the transition from full compensation to in-phase compensation is realized,the pressure of detection unit is reduced,and the adaptability of DVR to the load is enhanced.A voltage drop simulation scheme is designed for the test part.The voltage dropping is realized by the impedance voltage drop generator and the optimized compensation strategy is verified.By optimizing the compensation performance of the prototype,it is found that the compensation effect is greatly improved in the actual operation,which can meet the relevant provisions of the national standard.