Power Oscillation Suppression Strategy of Unbalanced Grid Based on EVCS-SMES Hybrid Energy Storage System

This paper proposes a power oscillation suppression strategy for unified power quality conditioner (UPQC) based on a hybrid energy storage system (HESS) consisting of the electric vehicle charging station (EVCS) and superconducting magnetic energy storage (SMES) during voltage unbalance. The proposed strategy provides dual protection for the grid side and load side, with the protection principles are analyzed respectively. The results show that the UPQC based on HESS has excellent compensation performance under unbalanced conditions. Meanwhile, the SMES protects the EVCS on the DC-side from power oscillations, and improves EV charging quality.