A Dynamic Voltage Restorer (DVR) based interface scheme for microgrids

This paper deals with the issues related to the interconnection between the microgrid and main network. The Dynamic Voltage Restorer (DVR) is proposed as an interface between the main network and microgrid in order to improve reliability and limit fault currents. The performance of DVR is demonstrated during fault conditions in two different locations, firstly in the main grid and then within the microgrid. The DVR is used to inject a voltage during a fault in the main grid isolating the microgrid from the fault and ensuring normal operation. Secondly, a novel technique is proposed employing the magnetizing inductance of the DVR series transformer in order to minimize the contribution of the grid currents during a fault within the microgrid. The proposed technique is evaluated using MATLAB/SIMULINK and shown to possess additional advantages when compared to traditional fault current limiters.