Optimum Droop Parameter Settings of Islanded Microgrids With Renewable Energy Resources

Droop control is a key strategy for operating distributed generation (DG) islanded systems, i.e., islanded microgrids (IMGs). The droop parameter settings of the DG units can significantly impact the ability of an IMG to feed its demand. This paper proposes a new probabilistic algorithm for determining the optimum choice for such droop settings for the individual DG units in a distribution network in cases when a microgrid central controller is unavailable. The proposed algorithm adopts a constraint hierarchy approach to enhance the operation of IMGs by satisfying the operational constraints of the system and expanding its loading margin. The new algorithm takes into consideration the variety of possible IMG configurations that can be initiated in a distribution network (multi-microgrids), the uncertainty and variability associated with the output power of renewable DG units as well as the variability of the load, and the special features and operational philosophy associated with droop-controlled IMG systems. Simulation studies show that the proposed algorithm can facilitate the successful implementation of the IMG concept by reducing the customer interruptions and enhancing the IMGs´ loadability margins.