Modelling and control of doubly fed variable‐speed pumped storage units for grid power regulation

With the expending scale of the power grid and the substantial development of renewable energy generation system, the demand for power quality is becoming more and more significant. The doubly fed pumped storage can be an effective method to control the power of the power grid and restrain the power grid fluctuation caused by renewable energy generation. First, this study introduces the structure of doubly fed pumped storage unit, and analyses the mathematical model of reversible hydraulic pump turbine, doubly fed induction generator (DFIG) and control strategy of the converter. On the basis of the model of reversible hydraulic pump turbine and DFIG, control strategies of the dq decoupling and synchronous rotating coordinate system are studied to output the active and reactive power. Second, the models of generating mode and pumping mode for the doubly fed pumped storage unit are established. Third, for the grid power regulation, active power and speed control strategy in generating mode, pumping mode are put forward. Finally, the model of doubly fed pumped storage unit of 300 MW is established in MATLAB/Simulink. The proposed control strategy is verified by the simulation results.