Hydraulic interference stability analysis and optimization of control strategies in pumped storage power plants with complex water conveyance systems

To address the unclear hydraulic interference propagation mechanism and the challenge of optimizing control strategies in complex water conveyance systems for pumped storage units, we construct a mathematical model of a one-pipe-two-unit and one-pipe-four-unit pumped storage power plant based on the method of characteristics and full characteristic curves. The influence of water conveyance system structural parameters on hydraulic interference stability is investigated. The results indicate that under one-pipe-two-unit layout, it can reduce the impact on the disturbed units by selecting the unit corresponding to the branch pipe with a larger water flow inertia time constant T_w as the interference unit. The analysis on one-pipe-four-unit system reveals that using two units on the same water conveyance branch as interference units can reduce the maximum rotational speed of the disturbed units. Finally, a governor parameter optimization model is developed aiming at the two configurations based on the NSGA-Ⅲ algorithm and the TOPSIS decision-making method. The optimized guide vane control strategy reduces the speed regulation time by 10. 59% and 12. 57% for the one-pipe-two-unit and one-pipe-four-unit configurations, respectively. These findings provide theoretical references for improving the hydraulic interference stability of pumped storage power plants operating under complex water conveyance systems.