An optimal secondary voltage control strategy for islanded microgrid

Abstract

In this paper, an optimal secondary voltage control (SVC) strategy has been proposed for an islanded microgrid(MG).The proposed strategy consists of multi-objective optimal function, power flow equality constraints and three sets of inequality constraints. The multi-objective function aims to minimize voltage errors of selected buses and reactive circulating currents among voltage modulation units by taking full advantage of both droop-controlled and PQ-controlled DER units connected in the MG. Power flow equations for the islanded MG were considered as equality constraints. Limits of DER capacities, bus voltages and power flows on distribution lines, must be met during the process of solving this proposed control strategy iteratively using interior-point algorithm. Finally, simulation results have been presented validating the proposed SVC scheme, illustrating good voltage regulation while minimizing reactive circulating current in islanded MG.