Centralized Unbalanced Dispatch of Smart Distribution DC Microgrid Systems

This paper proposes three new operation strategies such that a set of dc microgrids in distribution systems can cooperate pursuing particular objectives: 1) loss reduction; 2) full unbalance compensation; and 3) partial unbalance compensation. Loss reduction is a regular strategy for distribution utilities operating their systems efficiently by optimal dispatch of three-phase in/out powers of dc microgrids. Full and partial unbalance compensation strategies can solve single- or two-phase overloading problems of substation transformers temporarily and slow down their aging process. To validate the performance of the proposed operation strategies, several steady-state studies are performed in the IEEE 123-bus test system. According to the simulation results, the operation losses can be reduced by up to 34% with 15.2% DG penetration. The maximum single-phase loading of the substation transformer can be reduced by up to 30%.