Assessment of droop-controlled islanded microgrid maximum loadability

This paper presents an algorithm for determining the maximum loading factor of droop-controlled islanded microgrids. The problem is formulated as an optimization problem to consider both the static voltage stability constraints and the small-signal stability constraints. A detailed microgrid model is adopted to reflect the special features and operational characteristics of droop-controlled islanded microgrid systems. The proposed problem formulation considers the system reactive power requirements and the different possible load characteristics. The optimization problem is subject to different system operational constraints including; the power flow constraints, voltage and frequency regulation constraints and unit capacity constraints. Different numerical case studies have been carried out to test the effectiveness and the robustness of the proposed algorithm.