Hydraulic-mechanical-electric Coupled System Modeling And Stability Analysis

Modeling of hydraulic-mechanical-electric system is an important foundation for mutual influence optimal operation of hydropower stations to study the hydraulic,mechanical,electrical system,however,in the present study of hydroelectric system,due to hydraulic,mechanical,electrical systems have differential equation solution and big difference,and the involved device is quite complex and covers a wide range of knowledge,it is difficult to establish detailed hydraulic-mechanical-electric model.Each system has different research directions,in most cases,electrical systems and hydraulic systems are usually experted in their respective fields of research and analysis,but due to different emphases in the study of each system,a number of relatively small impact factors that would be normally simplify and neglect appropriately.The mismatch of model precision and lack of hydraulic-mechanical-electrical system model are the main reasons for restricting the transient study and improvement of simulation precision on hydroelectric system.Therefore,this paper uses state-space system eigenvalue analysis method to calculate the eigenvalues of the coefficient matrix A and summarize the distribution of all eigenvalues and stability analysis.An integral coupled hydraulic-mechanical-electric system is established in Matlab/Simulink environment.Based on this model,the interaction between systems is studied and simulation results are given and analyzed.The main contents of the thesis are listed as follows:(1)Hydropower that units of hydraulic,mechanical,electrical system model is researched,The process of hydraulic,mechanical and electrical motion transition is comprised,which is based on coupling model MATLAB/Simulink platform.(2)Through the study of hydraulic,mechanical,electrical system model,This paper has finished the mathematical model of each system and used state-space system eigenvalue analysis method to calculate the coefficient matrix eigenvalues of A.All the features of the distribution of roots are used to analyze the performance of the control system.And the results are compared with the simulation graphics verified.(3)The influences of electrical and hydraulic system on coupled system are based on single machine infinite simulation system,which include the impact of electrical disturbance,constant mechanical power model and parameters of excitation system.The effect of the hydraulic system model is studied,which include the impact of hydraulic disturbance,hydraulic system models and hydraulic system parameters.