Effectiveness of applying pressure regulation valve to hydro turbine governing system and its multi-objective control optimization under load rejection

Pressure regulation valve is taking a growth share of the hydropower market due to its low construction cost, short construction period and high maintenance convenience, the control problem of pressure regulation valve is attracting more and more attentions in the engineering community. This paper studies the integrated control law of pressure regulation valve and guide vane in hydropower stations. Firstly, a refined hydro-turbine governing system model is established to describe the nonlinear hydro-mechanical-electrical characteristics of the system as well as the hydraulic characteristics of pressure regulation valve. Then, the effectiveness of applying pressure regulation valve to hydropower stations is validated via comparative simulations. Result indicates that pressure regulation is able to significantly reduce the pressure oscillations in volute but has little effect on the draft tube pressure. Then, a novel multi-objective optimization strategy for the joint operation of pressure regulation valve and guide vane is proposed, which optimize rotational speed and volute pressure. Optimization result indicates that the control performance can be significantly improved by the proposed optimization strategy, the optimized joint operation scheme reduces the maximum increase of volute pressure and rotational speed by 29.8 and 5.9%, respectively.