Abstract: In the distribution system，voltage sag or swell will cause unexpected power load outage. Dynamic Voltage Restorer（DVR）is usually used to compensate the grid voltage. DVR detection unit should have good dynamic performance to detect voltage amplitude and phase changes in order to trigger DVR in the rapid compensation of distribution network voltage fluctuations. In order to improve the power quality in power system，a DVR control strategy based on double loop vector decoupling control was proposed to improve the dynamic performance of DVR in compensation process. The experimental results show that the proposed control strategy can correct voltage sags more quickly than the traditional method，make DVR achieve better dynamic performance，and ultimately improve the power quality of the grid.

Key words: dynamic voltage restorer（DVR）, vector control algorithms, voltage sag, voltage swell