Numerical Modeling and Simulation of a Variable Speed Pumped Storage Unit along with Experimental Verification

This article studies the method of constructing a refined numerical model of water, machinery, and electricity for a variable speed pumped storage unit based on the MATLAB platform. Firstly, the overall model architecture of the variable speed pumped storage unit is introduced, including the hydraulic mechanical subsystem and the electrical subsystem. The hydraulic mechanical subsystem mainly consists of modules such as water pump turbines, upstream and downstream reservoirs, pressure pipelines, pressure regulating chambers, and speed controllers, while the electrical subsystem includes modules such as doubly fed induction motors, inverters, and power grids. Subsequently, the mathematical models and control strategies of the doubly fed induction motor and inverter in the electrical side model were elaborated, as well as the modeling methods of the water pump turbine, pressure pipeline, regulating chamber, upstream and downstream reservoirs, and governor in the hydraulic mechanical side module. Among them, the water pump turbine adopts the improved Suter curve processing method, while the pressure pipeline and regulating chamber are modeled based on the characteristic line method (MOC). Experimental comparisons were conducted using the empirical platform of variable speed pumped storage units at the National Key Laboratory of Hydraulic Engineering, Wuhan University. The experimental results show that under the two control strategies of power priority and speed priority, the model simulation results are highly consistent with the physical experimental results, with a maximum error of no more than 10%, verifying the reliability and accuracy of the model.