Formation of Islanded Droop-Based Microgrids with Optimum Loadability

This paper proposes a new model for the optimal partitioning of active distribution networks into a number of islanded microgrids. The objective of the developed model is to maximize the minimum value of maximum loadability amongst formed islands to create resilient islanded microgrids against unexpected local disturbances and power mismatches. The model takes key aspects such as the operation of islanded microgrids using droop control, system tie-lines, and line capacity limit into consideration. An ear decomposition-based method is proposed in order to preserve the radiality of formed islands. Besides the formulated exact optimization model, which is a nonconvex formulation, two convex mixed-integer models are introduced to achieve a trade-off between solution accuracy and computational time. The numerical results demonstrate the effectiveness and robustness of the proposed models in forming droop-controlled islanded microgrids with optimum loadability.