Hydraulic Coupling Suppression Control Method for Complex Hydraulic Systems Based on Feedforward Synergetic Compensation of Guide Vane Opening

With the increasing scale of cross-basin hydraulic engineering and cascaded hydropower stations, hydraulic systems exhibit complex characteristics such as long-distance, nonlinear, and multivariable coupling. The dynamic interaction among hydraulic parameters can easily induce pressure oscillations and flow fluctuations, posing a serious challenge to the safe and stable operation of the system. To address the control problem caused by the impact of hydraulic coupling on the output of complex hydraulic systems, this paper proposes a synergetic feedforward control method based on the rate of water level change in the surge tank. This method uses the rate of water level variation as a real-time indicator of hydraulic coupling intensity and, through theoretical derivation, establishes an analytical relationship between the guide vane opening compensation and the rate of water level change for each unit. For complex topological configurations, the feedforward weight coefficients are separately derived for single penstock–single machine systems and single penstock–two machine systems. Theoretical analysis shows that the proposed method automatically resets to zero under steady-state conditions, fundamentally eliminating the issue of steady-state opening deviation. It also exhibits phase-leading characteristics, enabling it to act in advance during the early stage of a disturbance. In addition, filtering is applied to suppress wave spikes that occur under certain parameter settings. Simulink simulations have verified the effectiveness of this method in mitigating hydraulic coupling, and the influence of key parameters on control performance has also been analyzed.