一种补偿电网电压凹陷的DVR优化补偿策略

An optimized compensation strategy of DVR for gird voltage sag compensation

针对电网中敏感负荷引起的电压凹陷问题,以及提高动态电压恢复器(DVR)的补偿质量,提出了一种优化的综合补偿策略。首先,详细分析了DVR三种基本控制策略的补偿电压与功率流动,推导出最大跌落支持时间;然后,提出了一种跌落前补偿向最小能量补偿过渡的优化综合补偿策略,利用一次过渡曲线将跌落前补偿的电压幅值与相角逐渐过渡到最小能量补偿的值,物理意义明确,减小电压相位跳变的同时增加补偿时间。算例分析结果表明,该法较单一补偿方法显著增加了DVR的补偿时间。仿真结果验证了该方法的有效性。

To solve the voltage sag problems of grid caused by sensitive load and improve the compensation efficiency of dynamic voltage restorer （DVR）, an optimized comprehensive strategy is proposed. 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 transition curve, which involves the injected voltage phases ofpre-sag strategy and minimum energy strategy, is used to transform pre-sag compensation to minimum energy compensation of DVR. 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. This work is supported by National Natural Science Foundation of China （No. 51477070）.