Development of Fast Response Technology Using Data Center On-Line UPS

Data centers in South Korea are expected to grow rapidly, particularly in the Seoul metropolitan area, raising concerns over declining grid flexibility and power system stability. This study proposes a control strategy to utilize the electrical load supported by data center on-line Uninterruptible Power Supply (UPS) systems as a flexibility resource for grid stabilization. The response speed and short-term energy storage characteristics of on-line UPS were analyzed and compared with those of Energy Storage Systems (ESS). Dynamic simulations were conducted under various Korean power system operating scenarios to evaluate frequency and voltage stabilization effects. The results show that a 1.05 GW UPS load-shedding event achieves frequency nadir and recovery performance comparable to a 1GW ESS deployment, while also contributing to voltage stabilization in metropolitan areas. In addition, the potential to alleviate certain generation constraints in the East Coast region was identified. To assess the power quality impact of UPS transfer, Electromagnetic Transient (EMT) analysis and field tests were performed, confirming no harmful effects on data center IT loads. This study demonstrates that UPS-based load-shedding in data centers can serve as a rapid flexibility resource at a level comparable to conventional ESS solutions.