Hierarchical Control and Experimental Verification of a Novel DC Substation

DC substation with three and more terminals is an important element for interconnected DC grid. This paper aims to explore the configurations and operation strategy of DC substation. A series of DC substation topologies have been derived in duality of classical AC substations. Among the derived counterparts, ring type DC substation is selected and developed for integrating two DC windfarms with two individual DC grids. To achieve the multiple operation aims of voltage regulation, power dispatching and fault protection, a hierarchical control is proposed. Prototype of DC substation has been built and tested in an experimental DC grid to validate the proposed topology and operation strategy.