Coordination control of medium-voltage hybrid ac/dc distribution

Hybrid ac/dc distribution has attracted much attention recently. This study presents a medium-voltage (MV) hybrid ac/dc distribution consisting of various distributed generations connecting to the ac and dc loads. Coordination control in hybrid ac/dc distribution is a challenging issue to achieve stability especially when there is a load rejection or loss of the generation. A new decentralised control is proposed to coordinate the hybrid ac/dc distribution even when the inter-station telecommunication is not available. A new control is employed at interlinking converter (ILC) to maintain the power balance between ac and dc subgrids, and to ensure that the power quality is maintained in normal operating condition as well as in an extreme abnormal condition such as island mode. Further, a new control strategy is developed in battery storage system (BES) as a backup device to minimise the power fluctuation in the event of the shedding of the loads or generations. Another advantage of the combination of ILC and BES controllers is to provide a multiple slack terminals in both ac and dc grids, which will enhance the stability in the system. Simulation results have shown that the stability performance can be achieved in various operating scenarios.