Simulation And Study Of Hydraulic Transient For Non-Pressure And Pressurizd Diversion System Of Hydropower Station On Matlab/Simulink

In recent years,with the shift of China’s hydropower energy development focus and the development of inter-basin water diversion projects,the construction of cascade hydropower stations and long diversion power stations has gradually increased.The water diversion system of these two types of power stations often uses a complex water diversion system combining non-pressure and pressurized.Compared with the traditional water diversion system,the hydraulic transient of the non-pressure and pressurized diversion system of hydropower station generation system is more complicated.Previous studies have focused on the transition process of water diversion systems with non-pressure or pressurized.There are few research results in the joint calculation of the complex system as a whole.Therefore,the research on the hydraulic transient of non-pressure and pressurized combined water diversion power generation system has important theoretical value and application prospects.In this paper,the mathematical models of the non-pressure open channel,the pressurized pipeline,the turbine regulation and the electrical subsystems are studied.Then based on Matlab/Simulink platform,the overall numerical model of hydropower station combined with non-pressure and pressurized water diversion system is established.And the simulation model is used to study the transition process of the non-pressure and pressure combined diversion power generation system.The specific research contents and results of this paper are as follows:In the first part,according to the characteristics of the diversion power generation system combining non-pressure flow and pressurized flow,the whole water electromechanical system is divided into three parts.Using simulation modeling software Matlab/Simulink visually models each system and encapsulates them into subsystem modules,which enhances the versatility and flexibility of the model.Finally,the simulation calculation model of the hydropower station transition process combined with the nonpressure and pressurized water diversion system provides a reliable tool for subsequent analysis and research.In the second part,using the established simulation model of hydropower station combined with non-pressure and pressurized water diversion system to analysis the hydraulic transient: the large fluctuation,small fluctuation and hydraulic disturbance transition process.The influence of the open channel water fluctuation on the transition process of the diversion power generation system is analyzed.The results show that the power plant regulation guarantee parameters obtained by the joint simulation of non-pressure and pressurized are more dangerous than the calculation results obtained by neglecting the influence of open channel.For the small fluctuations and hydraulic disturbance of the power station,due to the slow decay of the open channel water fluctuation,it will affect the running unit for a long time,which leads to the wake wave of the unit speed regulation process,so the unit adjustment time is increased more than the unit adjustment time obtained by ignoring the influence of the open channel.In the third part,simulation of the complex diversion power generation system of “open channel + pressure tunnel + surge tank + pressurized pipeline” is carried out,and the differences between the transition process of the power station when considering the influence of open channels and ignoring the influence of open channels are analyzed in depth.The superposition of the fluctuation of the mass wave of the open channel gravity wave and the water volume of the surge tank is verified,and studies the influence of the open channel size on the wave superposition.The results show that the degree of superposition is mainly related to the period of the two wave.When the two fluctuation periods are close,the fluctuation amplitude of the surge tank water level and the open channel water level is the largest during the transition,and the effect of fluctuation stacking on the unit is most significant.Finally,the numerical simulation model is used to study the small fluctuation and hydraulic disturbance transition process of the open channel to the pressurized water diversion system with surge tank.The results show that the fluctuation period of the surge tank increases when the influence of open channel is considered,and the speed wake is changed.During the change process,the unit speed adjustment time increases and the turbine system adjustment quality decreases.In this paper,the numerical simulation overall model of hydropower station combined with non-pressure and pressurized water diversion system is established.The transition process of non-pressure flow and pressurized flow combined water diversion power generation system is calculated and analyzed in detail.Based on the model,the influence of the open channel water level fluctuation on the transition process of the power station is studied,and the fluctuation law of the mass wave because of the open channel gravity wave and the surge tank are research,which provides theoretical guidance for the design of the open channel size in the actual project,and similar complex water diversion power generation for the future.It has important reference value and application prospect for the construction and safe operation of similar complex water diversion power generation systems in the future.