Enhancing the performance of multi-microgrid with high penetration of renewable energy using modified droop control

Abstract

Currently, Microgrids (MG) have given high attention due to their ability to increase power systems reliability and controllability. Also, small-scale renewable units are increasing according to the distribution of renewable energy. In this paper, a hybrid MG (H-MG) is proposed. This H-MG includes AC and DC buses, two voltage levels, linear and nonlinear loads, and different distributed generators such as diesel, wind, and PV besides storage units. Modified angle droop control is utilized in the coupling inverters between DC-MG and AC-MG because it leads to a much smaller standard frequency deviation than conventional droop control. Also, to enhance the intermitted sources of energy sharing and the system characteristics of damping, an additional control loop is introduced. Where, both the voltage angle and the voltage magnitude are corrected by adjusting the output of the droop controller. Moreover, due to the high R/X ratio of the study system as in rural area, the proposed angle droop control is enhanced by using some transformation to amend both the feedback gains and the droop equations to account for the high coupling between active and reactive power and enhance power-sharing in such case. Various simulation studies are executed and compared with the related works to show the efficiency and quality of the proposed MG operation.