Transient Time-delay Stability Analysis of the Distributed Coordination in AC Microgrids

Microgrids, as the promising solutions to the sufficient employment of various energy sources, have attracted numerous attention recently. By the coordination of multiple microgrids, distributed generators can be unified as an organic system reasonably and properly, enhancing the individual reliability and the resource dispatch. While the microgrid cooperation interlinks different microgrid units, time delays during the information exchange remain to be uncertain risks for the whole system, which should be explicitly investigated considering potential oscillations incurred by time delays. To addresses this gap, this paper establishes a transient time-delay model for the stability analysis of coordinated microgrids with the distributed control strategy. The physical dynamics and cyber latency are integrated into the proposed state-space model, which forms a convenient interface for the stability analysis. In addition, the time-delay impact channel is revealed from the insights of the system structure illustrating the time-delay impact systematically. Case studies demonstrate that time delays would induce unstable impacts for the microgrid with coordinated generators, which also correlates with the power allocation within the microgrid.