Operations and Coordination of Dual-Functional DVR and Recloser in a Power Distribution System

Dynamic voltage restorers (DVRs) are devices that compensate for voltage sags/swells in power distribution systems effectively. However, the performance of DVRs may be easily endangered by large load-circuit currents. This work proposes a dual-functional DVR (DFDVR) that solves multiple problems by controlling the trigger angle of antiparallel thyristors, which are connected between the power converter and output filter. The DFDVR not only compensates for voltage fluctuation in the upstream grid but also limits fault current in the downstream grid. Moreover, the combined application of the DFDVR with a recloser is introduced. The DFDVR flexibly regulates the amplitude of the faulty current to coordinate the recloser. In addition, the coordination sequence diagrams of the DFDVR and the recloser under instantaneous and permanent faults are analyzed in detail. Simulations and experimental results verify the correctness and feasibility of the operations and coordination of the DFDVR and the recloser.