Optimal Dispatch and Techno-economic Evaluation of Mixed AC and DC Distribution Networks with High Penetration of Photovoltaic Panels

Abstract

AC and DC hybrid power distribution can increase the flexibility of the power system, thereby increasing the consumption rate of renewable energy. Power electronic transformer (PET) is modeled as the key interface between AC and DC network connected at the bus of mid-voltage distribution system with high penetration of photovoltaic (PV) panels. This paper evaluates the cost-effectiveness of the PET-based AC and DC distribution network with power system reliability constraints. A combined optimization of PET configuration and operation is formulated as a two-stage optimization problem for minimizing the operating cost and power losses. The optimal configuration and operation of mixed AC and DC network are solved iteratively in the two-stage algorithm. The economic performance of PET-based network is compared to a corresponding AC distribution system. A 33-bus test system is simulated with distributed PVs and PETs installed at the buses of mid-voltage AC network. The simulation results show the merits of mixed AC and DC network in terms of operating cost and PV integration.