摘要
该文对基于级联逆变器的动态电压恢复器(DVR)进行了电压跌落补偿策略研究,通过不同跌落程度下的补偿策略分析,推导出DVR补偿时注入有功和负荷功率因数之间的关系。功率因数越低,DVR补偿时消耗的能量越小,越容易实现纯无功补偿。据此,该文对DVR接入系统的拓扑结构加以改进,在负荷端并联一个可调电抗器,电压跌落补偿时投入使用,暂时降低负荷功率因数,以保证DVR在补偿时消耗能量最小。仿真结果表明,暂时降低负荷功率因数的最小能量补偿策略可以有效降低DVR补偿时注入的能量,扩大纯无功补偿的电压跌落范围,延长补偿时间。
A method for sag mitigation based on a cascaded inverter DVR（Dynamic Voltage Restorer） with energy storage capability is studied.Through the analysis of phasor diagram and sag mitigation in different situations,the functional relation between DVR compensation capability and load power factor is obtained.It is found that energy consumption is more less with little load power factor and the pure reactive compensation is easier to be achieved.According to these conclusions,the topological structure of DVR connected to the system is improved in this way that a thyristor switched adjustable inductor is added in parallel with the load which is carried out when the DVR is compensating sags.Minimum power consumption is achieved with temporary reduction of the power factor by the thyristor switched adjustable inductor.Simulation results show that the proposed method can effectively reduce the power injection in compensation by DVR,enlarge the voltage sag range of pure reactive compensation and longer effective compensation duration.
出处
《电气自动化》
2010年第4期63-65,共3页
Electrical Automation
