With the large-scale application of microgrid

microgrids with single-phase/three-phase architecture geographically closer to one another can be interconnected to multi-microgrid systems with multi-phase architecture. For the regional autonomous multi-microgrid off the power distribution network

this paper proposes a distributed-coordinated hierarchical control strategy of multi-time scale

including second-level distributed real-time control

minute-level centralized coordinated control and hour-level dynamic island switching control. Distributed real-time control achieves power regulation with sources

loads and storages based on each microgrid's stability margin. Considering the three-phase unbalance factor as a constraint

centralized coordinated control achieves regulation of power with sources

loads and storages based on multi-objective mixed integer programming. Dynamic island switching realizes optimal resources allocation for the whole regional multi-microgrid through combined decision making. It is shown by simulation results that the proposed strategy can realize hierarchical control on multi-time scale for the regional autonomous multi-microgrid with single-phase/three-phase architecture and the coordinated control of the fluctuation of sources

loads and storages to help with the safe and efficient operation of the multi-microgrid off the distribution network. This work is supported by National Key Technologies R&D Program(No. 2015BAA06B02).