A Novel γ Control for Enhancing Voltage Regulation of Electric Springs in Low-Voltage Distribution Networks

Electric springs (ES) have been reported as a distributed means to address the voltage instability issues at the point of common coupling (PCC) in low-voltage distribution networks (LVDN). In the reported research works on the control methods of the ES, it is generally assumed that the grid networks are predominately inductive. This assumption is fundamentally flawed as the line impedances are significantly resistive in LVDN, which leads to deteriorated voltage regulation effects. To address this, a novel gamma control method is proposed to enhance the voltage regulation performances of the ES in LVDN. A comprehensive steady-state model of the ES-based smart load considering different Thevenin's equivalent line impedances is developed in this article. Equivalent regulation points and optimal operating regions of this smart load are derived analytically. The proposed control embeds a smart load model and enables adaptive control boundaries of the ES, which can avoid the suboptimal or positive-feedback operations in the PCC voltage regulation. Besides, a hysteresis proportional integral (PI) controller is designed to mitigate the voltage flickers. Experimental and simulation results have been provided to verify the effectiveness of the proposed gamma control.

Automated summary

Electric springs (ES) are suggested as a solution for voltage instability in low-voltage distribution networks (LVDN). However, existing control methods for ES assume predominantly inductive grid networks, which is flawed as LVDN has significantly resistive line impedances. To address this, a novel gamma control method is proposed to enhance the voltage regulation performance of ES in LVDN. A comprehensive steady-state model of the ES-based smart load considering different line impedances is developed and optimal operating regions are derived analytically. The proposed control incorporates a smart load model and enables adaptive control boundaries, avoiding suboptimal or positive-feedback operations in voltage regulation and mitigating voltage flickers with a hysteresis proportional integral (PI) controller.