Mode Transition Strategy for Three-phase/Single-phase Multi-microgrids Under Fault Condition of Distribution Network

When the fault occurs in distribution network, it is critical for stability operation of multi-microgrids (MMGs) to transit seamlessly to regional autonomy state. In this paper, the passive-to-islanding transition strategy is proposed based on centralized-distributed control. At first, when the static switcher of multi-microgrid switches off, the decentralized autonomous control is executed in each sub-microgrid immediately to reduce the power delivered by main power sources. Then, the power output of loads and photovoltaic sources are allocated based on mixed integer programming obtained by using fast particle swarm algorithm, and are recovered centrally. In the end, the simulation result indicates that the proposed strategy can achieve the seamless switching for three-phase/single-phase MMGs under the fault condition of distribution network.