Research On Comprehensive Characteristic Curves Model Of Hydraulic Turbine And Transient Process Calculation For Hydraulic Unit

Hydraulic turbine is one of the important power equipment in electric power production.The operation of hydroturbine is directly related to the safe operation of hydropower station.China is a great country with lots of generation or under construction in the large and medium-sized hydropower station,so the comprehensive detailed studies on the characteristics of the hydraulic turbine has important engineering significance.The inside of the water turbine hydraulic flow is very complicated,Model synthetic characteristic curve obtained by model test mainly reflects the static characteristic in turbine performance at high efficiency,while turbine characteristic need to be considered in the study of hydroelectric generating set control and calculating of transient process of hydropower station and so on,which requires extension and high precision of model synthetic characteristic curve and mathematical modeling.According to the high efficiency area characteristic curve of the turbine,runaway characteristic curve and zero torque characteristic curve when the opening,combined with the theory of Francis turbine flow field analysis and a large number of mathematical relationship between the model test of turbine characteristic parameter,then expanding the features of high efficiency area on this basis,besides setting up hydraulic turbine characteristics mathematical model based on the double cubic B spline.Francis turbine is the most common hydroturbine type,applying the theory and method to obtain the turbine characteristic of several kinds of typical specific speed,then establishing the universal database of Francis turbine characteristics,finally optimal point consistent principle is applied to make the characteristic database applicable for hydroturbine with any specific speed.The calculation of transient process for hydraulic unit involves modeling and solving two parts.The nonlinear model of hydraulic turbine,the time-delayed differential equations group of pressure water diversion system,the equation of motion and actuator equation,in mathematics,general its abstract into a composed of ordinary differential equation and algebraic equation of differential algebraic equations,namely DAE(differential algebraic equation).So the calculation of the transient process is transformed into solving the problem of DAE issue.Using the discretization method and elimination method or directly called the ODE solver method to solve such problems Hessenberg-type 1 DAE issue.Considering the different DAE system of rigid strength,in-depth study of the most effective method.In order to facilitate the calculation of transition process,developing the visual calculation simulation platform of transient process for hydropower station,incuding universal characteristic database of Francis turbine and considering several water diversion system,and designing the calculation parameter input interface of the transient process of hydropower station alone with the GUI interface of dynamic real-time display.Taking a specific power plant as an example,For two typical big oscillation transient process as load rejection and start-up process,which obviously reflects the changes of the parameters in the transient process and its track in the characteristic feature.