A Wireless Load Sharing Strategy for Islanded Microgrid Based on Feeder Current Sensing

摘要

To solve the reactive power sharing issue in droop control application, many solutions have been developed based on the basic wireless manner. However, existing wireless methods cannot eliminate reactive power sharing errors effectively, especially in load change situations. In this paper, a wireless reactive power sharing method that employs feeder current sensing and adaptive virtual impedance control is proposed for islanded microgrid. To improve reactive power sharing accuracy of virtual impedance method, an equivalent feeder concept is introduced, which can reflect the mismatch in connecting circuits equivalently. Through fast feeder current sensing, distributed generation units can calculate their respective equivalent feeders in real time. With the cooperation between real-time calculation and virtual impedance control, the proposed method achieves both accurate and fast performance in reactive power sharing. Compared with communication-based methods, the proposed wireless control provides the same high accuracy in reactive power sharing; meanwhile, its response speed to load change is much faster than that of other methods. Moreover, the proposed method can work as normal even though load changes during the transient process. Matlab simulation and real-time digital simulator test are used to validate the feasibility of this method.