| Abstract: | 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 compensationmethod. Furthermore, high-power consumption of the phase jump compensation increases the size and cost of adynamic voltage restorer (DVR).Methods & Results: In order to improve the compensating efficiency of DVR, an optimized compensation strategyis proposed for voltage sag of micro-grid caused by interconnection and sensitive loads. The proposedcompensation 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 basiccompensation strategies. Then, the phase jump is corrected by pre-sag compensation. And a quadratic transitioncurve, which involves the injected voltage phases of pre-sag strategy and minimum energy strategy, is used totransform 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 proposedstrategy increases the supporting time for long voltage sags. The analytical study shows that the presented methodsignificantly increases compensation time of DVR. The simulation results performed by MATLAB/SIMULINK alsoconfirm the effectiveness of the proposed method. |
