Stability Analysis for Forebay Water Level Control of Hydropower Plant Considering Nonlinear Hydraulic Turbine

Water level control plays an important role in the operation of hydropower plants with forebay. This work explores the stability and dynamic characteristics of the hydraulic turbine regulation system under forebay water level control. First, a simulation model based on MATLAB/Simulink was established. In the turbine sub-model, a nonlinear model fitted to the full characteristic curves was established, as opposed to a linearized model commonly used in previous studies. Next, the stability region of the system was derived using the Hurwitz stability criterion based on the simulation model. A stability analysis was conducted by comparing and verifying with the time-domain simulation results. The results indicate that the proposed nonlinear model sufficiently meets the requirements for theoretical analysis. This study provides theoretical support for optimizing the water level regulation strategy of the forebay and improving the system response capability.