Characteristic Analysis Of Typical Transient Of Pumped Storage Power Station Based On Characteristic Curve

With the rapid development of China's power system,the structure of energy is constantly becoming stable and efficient.Pumped storage power station plays the role of loading peak removal and loading valley filling in the grid,with the strong flexibility,and it has a significant impact in improving the quality of the power grid.Therefore,it develops very rapidly in recent years.During the operation of the pumped storage power station,the pump turbine regulating system is the core of the pumped storage power station,and its safety and stability have an important influence on the power generation process.Especially in the process of large fluctuation,the unit parameters change dramatically and the flow regime change complexly,which has a violent influence on the operation stability of the unit.Therefore,this paper reveals the nonlinear dynamic behavior of the transition process from the point of view of the system and reflects the nature of the transition process,providing a theoretical basis for safe and stable operation of the power station.The object of this paper is the mixed-flow pump turbine regulating system.Based on the measured data of the pumped storage power station,the characteristic curve is fitted and the dynamic transfer coefficient is calculated by the external characteristic method.The change of the transfer coefficient can be used to show the characteristics of the pump turbine unit during the running process.Further,a mathematical model of pump turbine is established based on actual data to reflect the nonlinear dynamic characteristics of the system.Summing up the whole process of the research,we mainly get the following several aspects of content:(1)The dynamic transfer coefficient curve is obtained from the measured data by using the external characteristic method,and the transfer coefficient is introduced into modeling process of the pump turbine regulating system.A nonlinear mathematical model is established for the load rejection of the pump turbine.The parameters are adjusted by the PID governor,and single regulating process of previous parameters pk,ik and dk is extended to the mutual influence of three relations.So we can get the best combination of parameters for the stable operation of the pump turbine,and utilize MATLAB to analyze the impact of every parameter.(2)In this paper,we study the process from the pump operating condition to the turbine condition,and carry on the in-depth analysis on the grid connection process.The dynamic transfer coefficients of the whole process are calculated,and the operating condition of a certain point in the past is extended to the whole transition process.Based on this,the mathematical model of the whole transition process is established.The simulation results show the characteristics of the stability of the unit with the change of the guide vane opening.In addition,the Hamiltonian control theory is introduced into the pump turbine regulating system,and the parameter stabilization during the process of turning on the grid is analyzed.Utilizing the numerical simulation,we obtain the change law of the power angle in the boot process with the guide vane opening changing.The result verifies the effect of Hamiltonian theory on the stabilization of generator system parameters.(3)Because the pump turbine unit is easy to enter the anti-pump condition at the moment of the boot and this will lead to the failure of grid,the fractional theory is introduced into the pump turbine regulating system.And we study the influence of fractional modeling on guide vane opening and on system speed.By calculation of the numerical simulation,the fractional order method in the process of achieving a quick boot has the theoretical guiding significance.