Hydraulic Turbine Guide Vane Closing Law Optimization And Predicting The Transition Process Using Inversion Analysis

With the transformation and development of our economy and society and the continuous promotion of the strategic goal of"carbon peak,carbon neutralization".As an important source of renewable energy,hydropower station plays an important role in China’s economic development,energy supply,environmental protection,natural disaster prevention and control and local economic development.During the operation of hydropower plant,optimizing the closing rule of guide vane is a main control measure for the transition process of large fluctuation under extreme conditions of hydropower plant,and is also one of the key methods to solve the operation safety and regulation of hydropower plant units.The evaluation index of guide vane closing law is optimized to make the water hammer pressure and speed of unit more reasonable during the transition process and meet the requirement of adjustment guarantee calculation.Based on the measured data of several hydropower stations and starting from the closing law of turbine guide vanes,this paper is based on the actual measurement data of several power plants,starting from the hydraulic turbine guide vane closing law,simulation modeling of different working conditions of the transition process of hydropower plants,based on which the optimization of the hydraulic turbine guide vane closing law and inversion prediction of the transition process are carried out and new methods are proposed,and the innovative points of the paper include:（1）In order to ensure the operational safety of hydropower plants under large fluctuation conditions such as turbine load shedding,a multi-objective optimization model of hydraulic power plant guide vane closure law is constructed with a"single-tube,double-engine"hydropower plant as the research object,a global optimization method for solving the model is discussed,and the cuckoo-coupled gray wolf optimization algorithm is applied to optimize the hydraulic turbine guide vane closure law.The results demonstrate the effectiveness of the model and the method,considering the constraints of each link and introducing a constraint violation strategy for the solution.（2）A new comprehensive robustness evaluation method is proposed by combining three control and protection parameters as evaluation indexes:ξmax,βmax and Hsmax,with the aim of studying the influence mechanism of different vane closing laws on the hydraulic transition process and the robustness of the vane closing laws:ξ_max,β_max and H_smax as evaluation indexes.The robustness evaluation results obtained by using this evaluation method.The robustness evaluation results obtained by using this evaluation method are basically consistent with the actual results,which can verify the reasonableness and reliability of the constructed evaluation method and provide a more suitable comprehensive evaluation method for the selection of guide vane closing law of medium and high head hydropower units.（3）Based on the improved SSA-VMD-WT denoising method,the measured signal of the load rejection condition of the hydropower station is processed,and the unit speed change process and the pressure change process of the spiral case and draft tube inlet obtained from the actual hydropower station engineering simulation are compared and analyzed through the hydropower station transition process simulation software.The results are in good agreement and the accuracy of the inversion simulation is high,which can meet the accuracy requirements of the prediction of the extreme control transition process of the power station,Provide basis for safe and stable operation of the power station.