Quantitative Comparative Study On Simulation Method Of Torsional Vibration Response Of Large Turbo-Generator

In the power system,various disturbances will produce the torsional vibration of the shafting,and the torsional vibration of the turbine generator shaft has become one of the important issues affecting the safe production of electric power.In this paper,the torsional vibration of large steam turbine generator sets is studied.Based on the structural characteristics of a 600 MW unit shafting,the effects on torsional vibration natural frequency,response waveform and amplitude under the electromagnetic torque addition method(uniform distribution electromagnetic moment and concentrated distribution electromagnetic),different simulation methods(Riccati transfer matrix method and finite element method)and different boundary condition types(Electromagnetic torque excitation,torsional angular excitation,torsional angular velocity excitation,torsional angular acceleration excitation)are analyzed and compared.Research shows that the three methods are used to analyze the inherent characteristics of torsional vibration of shafting.Compared with the finite element method,the use of periodic symmetric boundary conditions can effectively simplify the calculation of the shafting modal frequency,improve efficiency,and save computation time;The transfer matrix method has higher computational accuracy than the finite element method in lower order modal calculations;For the response analysis,the results of the two electromagnetic torque addition methods have the same trend and amplitude,and the relative error is small.In the simulation analysis,the two electromagnetic torque addition methods can be used equivalently;In the analysis of the excitation form,the fatigue life loss of the shafting is higher than that of the electromagnetic moment excitation under the angular velocity excitation.The fatigue life loss of the shaft coupling is the largest under the torsional angle excitation,and the fatigue life loss of the coupling is the smallest under the excitation of the torsional angular acceleration.In the comparison of the two analytical methods,the transfer matrix method has great advantages in computational efficiency.The conclusions of this paper can provide some reference for the torsional vibration response and fatigue damage assessment of large units.