An Advanced Control Strategy for a Weak Grid-Connected DG for Enhancing Voltage Support During Co-occurrence of Sag and Swell

This project proposes an advanced control strategy tailored for weak grid-connected Distributed Generation (DG) systems to enhance voltage support during simultaneous sag and swell events. Weak grids are susceptible to voltage fluctuations that can disrupt power supply and compromise grid stability. In this paper proposed work presents a flexible reactive power control to enhance the voltage support during the CVSS in the phases of the system. It generates phasewise current references for controlling appropriate reactive power subjected to safe current limits when the voltage sag, swell, and coexistence are detected in the phases. Under normal system operation, the behavior of the proposed control is the same as conventional. The proposed control is implemented on the grid-tied three-phase four-leg inverter, and the experimentation results show the effectiveness of the proposed control. by using matlab/Simulink software 2018a.

Keywords: Current control, grid-tied converter, phasewise current control, voltage sag, voltage support, voltage swell, weak grid.