Stability and robustness of a coupled microgrid cluster formed by various coupling structures

Abstract

A standalone microgrid (MG) may frequently experience overloading owing to insufficient power generation or excessive renewable-based generation, which can cause unacceptable voltage and frequency deviations. Such problems are conventionally alleviated by load-shedding or renewable curtailment. Alternatively, autonomously operating MGs can be provisionally connected to facilitate temporary power exchange. The power-exchange link among the MGs can be of different types, e.g., three-phase ac, single-phase ac, or dc-link and power electronic converter-interfaced. All these topologies can facilitate power exchange, but they differ with regard to stability and robustness. In the present study, the stability and robustness of such structures are investigated, and the effects of factors such as the length of the interconnecting line among the MGs, the amount of power supplied to the troubled MGs, and the number of coupled MGs are compared. The stability and robustness of the structures are evaluated in Matlab.