An Advanced Droop Control Strategy for Reactive Power: Assessment in Islanded Microgrids

Inverter based islanded MicroGrids (MGs) are very fascinating but challenging ways to integrate Distributed Energy Resources (DERs) in electric networks. Active and reactive power regulation is a major issue due to the necessity of optimally exploiting the sources characteristics and controlling voltage and frequency. Focusing the attention on the reactive power control, the main needs are to regulate voltage at suitable values and ensure a proper reactive power sharing among the energy sources. The conventional control for reactive power presents relevant drawbacks and so an Advanced Droop Control strategy (ADC) is presented to approach primary voltage control and reactive power sharing among Grid-Supporting inverters in islanded MGs. The ADC strategy is presented defining its control law and the control scheme with a stability analysis. Then, an analytical procedure is developed to set the controller parameters. Following, a comparison between the ADC and droop control is performed with dedicated simulations on a common benchmark Microgrid in order to highlight the advantages of the proposed control strategy. Finally, a comparison with other advanced control techniques is proposed in order to show that ADC is able to guarantee improved performance in terms of the combined regulation of voltage and reactive power.