Enhancement of Frequency Regulation in AC-Excited Adjustable-Speed Pumped Storage Units during Pumping Operations. - Tan, Shuxin; Yan, Wei; Zhao, Lei; Zhang, Xianglin; Man, Ziqiang; Lu, Yu; Liu, Teng; Zhong, Gaoyue; Liu, Weiqun; Shi, Linjun (Energy Engineering, 2025)