| 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 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. |
