Comparative Study of Operating Characteristics of Doubly-Fed Variable-Speed Pumped Storage Unit Under Two Different Control Strategies

A Variable Speed Pumped Storage (VSPS) unit is able to effectively suppress fluctuations of the power system arising from the extensive incorporation of renewable energy facilities, whereas the most commonly applied unit is the one adopting a doubly-fed induction motor (DFIM). To investigate the support characteristics of doubly-fed VSPS unit under different control strategies, this paper establishes a nonlinear model and builds the control system, which is composed of an electrical control system and a hydraulic control system. Then based on the established model of the system, two control strategies of the VSPS unit are developed. Finally, a comparison of the unit's active power and speed response performance between the two control strategies is drawn by MATLAB/Simulink simulation. The advantages and disadvantages of each control strategy and their respective applicability are also analyzed, which provides a theoretical foundation supporting the design and operation of VSPS unit.