An Efficient Droop Control Strategy for Reactive Power Sharing Improvement and Stability Margin Enhancement in Islanded Microgrids

In islanded microgrids, distributed generation (DG) units employing the conventional droop tend to have a remarkable mismatch in the reactive power-sharing accuracy. This issue mainly arises from mismatches in line impedances. Besides, the imbalance in reactive power sharing can potentially compromise the overall stability of the system. Thus, this article proposes a control strategy that utilizes communication links to adaptively tune reactive power droop gains <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{n}_{\mathrm{q}})$</tex> to achieve accurate reactive power sharing among DG units while enhancing the stability margin of the microgrid. Unlike previous studies that mainly focused on the active power droop gain to control the stability of microgrids, this study offers a novel examination of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{n}_{\mathrm{q}}$</tex> parameter by highlighting its influence on both the stability margin of microgrids and the reactive power-sharing accuracy. The proposed approach was tested on a 34-bus microgrid benchmark and compared to three widely used control strategies: the conventional droop control, virtual impedance-based control, and a modified droop control introduced in the literature. The proposed control approach showed superior performance compared to other controllers and managed to achieve precise reactive power sharing while improving the stability margin by 137% compared to the conventional droop benchmark.