Three-level control architecture for hybrid AC/DC distribution grids

The integration of DC technology into existing AC systems represents a possible response to challenges at all grid levels. As consequence, hybrid AC/DC systems emerge providing more flexibility in grid operation. To guarantee secure and efficient network operation of these systems, adequate operating points for controllable devices such as converters are required. We present a comparison of suitable hierarchical control concepts for different types of hybrid AC/DC networks with focus on medium-voltage. For this purpose, we evaluate three different OPF formulations used for regular set point updates. The OPFs are tested on an adapted 511 bus MV network based on real data. Moreover, we provide solutions to locally adapt set points and topological fall back measures in case of outages or changes of system state including an overview of different local controllers for set point attainment and retention.