An Enhanced Reactive Power Sharing and Secondary Voltage Restoration Control in Islanded Microgrid

Abstract

In the islanded micro-grid, parallel distributed generators (DGs) are normally controlled with the aid of the droop control scheme. However, the droop control method is still concerned to improve the accurate of reactive power sharing and variation of frequency and voltage at the point of common coupling (PCC). This paper proposes a control scheme to solve the limitation of microgrid in islanded operation such as reactive power sharing accuracy and PCC voltage and frequency drop by using a close-loop of the virtual impedance to compensate the feeder mismatch between DGs. Therefore, the power sharing performance is improved, and the circulating current between DGs is suppressed. In order to achieve the accurate reactive power sharing and PCC voltage restoration, a secondary control is implemented in both the microgrid central controller (MGCC) and local controller by using the low bandwidth communications. The effectiveness of the proposed control method is analyzed through the simulation.