Handling the variability of renewable energies is a key for power systems towards de-carbonization and sustainability, and hybrid power system (HPS) is a promising solution for enhancing power generation by aggregating various energy resources. Meanwhile, the development, implementation and influence of variable speed pumped storage technology has been increasing all over the world. In this paper, a preliminary study on dynamic performance of variable speed unit (VSU) for hybrid photovoltaic-pumped storage power system is conducted. The main method here is numerical simulation based on timescale of seconds, by adopting MATLAB/Simulink. First, a mathematical model of the HPS is established, and a VSPSP and a photovoltaic power system are included. Then, the dynamic performance of the VSU in the HPS is simulated and discussed based on a quantitative comparison between the VSPSP and the FSPSP. The focus is to assess the two aspects: combined power output of the HPS and actuator movement. The results demonstrate the capability and advantage of applying the VSPSP for balancing photovoltaic power variation. Meanwhile, there is no fundamental distinction between the VSU and the fixed-speed unit (FSU) for the regulation movements that indicates wear and tear, despite the physical process and mechanism of active power regulation are different for the two types of pumped storage unit. The model and results could provide understandings on the detailed dynamic behaviors of HPS with VSPSP and photovoltaic power systems, for further supporting the operation and performance evaluation of HPS with multiple renewable energies.
Keywords variable speed pumped storage plant, photovoltaic power, hybrid power system, dynamic performance, Simulation