摘要
Introduction:This paper uses a dynamic voltage restorer(DVR)to improve the voltage quality from voltage sags.It is difficult to satisfy various of compensation quality and time of the voltage sag by using single compensation method.Furthermore,high-power consumption of the phase jump compensation increases the size and cost of a dynamic voltage restorer(DVR).Methods&Results:In order to improve the compensating efficiency of DVR,an optimized compensation strategy is proposed for voltage sag of micro-grid caused by interconnection and sensitive loads.The proposed compensation strategy increases the supporting time for long voltage sags.Discussion:Firstly,the power flow and the maximum compensation time of DVR are analyzed using three basic compensation strategies.Then,the phase jump is corrected by pre-sag compensation.And a quadratic transition curve,which involves the injected voltage phases of pre-sag strategy and minimum energy strategy,is used to transform pre-sag compensation to minimum energy compensation of DVR.Conclusions:The transition utilizes the storage system to reduce the rate of discharge.As a result,the proposed strategy increases the supporting time for long voltage sags.The analytical study shows that the presented method significantly increases compensation time of DVR.The simulation results performed by MATLAB/SIMULINK also confirm the effectiveness of the proposed method.
基金
supported by National Nature Science Foundation under Grant 51477070,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
