A Novel Design and Control Strategy of DVR for Fault Current Mitigation

This paper proposes an innovative topology and control algorithm of dynamic voltage restorer (DVR) for limiting the fault current in a grid connected power system. The method takes into account the effect of both balanced and unbalanced fault conditions affecting sensitive loads. The DVR acts as a voltage restorer during voltage sag conditions and as a fault current limiter during fault conditions. The fault current limiting (FCL) mode of DVR is analysed with two topologies, one with conventional crow bar switches and the other with out of phase DVR (OPDVR) in which an out of phase series voltage is injected into the grid. Analysis of the method is carried out in MATLAB/Simulink environment. The results obtained with the proposed method indicate that OPDVR has better performance as compared with the conventional FCLDVR mode of operation.