Numerical simulation and stability analysis of pumping transients in the pumped-storage power plant

The pumped-storage unit (PSU) are of great significance in modern power system for its reversible operating mechanism in both power generation and water pumping directions. Aiming at the precise numerical simulation of pumping transient processes in PSU, this paper establishes a nonlinear and characteristic method-based mathematical model of the governing system of PSU in which the hydraulic behaviours of conduit pipes, surge tanks and the pump turbine as well as the mechanical-electrical characteristics of the generator-motor are taken into consideration. In this model, local hydraulic losses in model boundaries are specifically introduced to compensate for the unmodeled errors. To verify the modelling accuracy, simulation curves under both pump failure and pump shutdown conditions are compared with the practical data. Furthermore, the hydraulic oscillations in the two transient processes have been discussed specifically.