Research And Application On Torsional Vibration On-Line Monitoring System Of Turbine Generator

With the rapid development of China’s power system and the in-depth adjustment of the energy structure,in order to improve the overall operating efficiency and economy,the turbine generator sets are developing towards large capacity and high parameters,and the torsional vibration of the guide shafting system is gradually prominent.At the same time,in recent years,in order to absorb wind,light,water and other clean energy in northwest and southwest regions,to a certain extent,it promotes the bundling and grid connection of new energy with thermal power and nuclear power units,so it will bring new challenges to the torsional vibration research of turbine units.After studying the basic torsional vibration model,this paper analyzes the advantages and disadvantages of the continuous mass model and the concentrated mass model as well as their application occasions,the finite element method and the transfer matrix method of modal calculation.Firstly,the multistage lumped mass model and transfer matrix method were used for torsional vibration modeling,and Newmark was used for transient response analysis.Secondly,the typical torsional vibration faults such as torsional interaction and short circuit caused by energy exchange imbalance in the electromechanical system are analyzed.Then,in order to improve the measurement accuracy of torsional vibration signal and the ability of monitoring and identifying faults of torsional vibration,a half-pulse periodic torsional vibration measurement method based on instantaneous angular velocity was proposed,and the sampling rate of the torsional angle was twice that of the traditional method.The correctness of the encoder model is verified by the preliminary simulation,and the applicable conditions are given:the relative sampling rate of torsional vibration signal C≥10.The measurement error caused by the vibration of the sensor bearing is analyzed,and the measurement method of removing the interference of the bearing is given.The effectiveness of the method is verified by numerical simulation and experiment,and the essential difference between the bearing vibration and the real torsional vibration signal to the speed pulse frequency modulation principle is analyzed.Finally,an on-line monitoring system for torsional vibration of a turbo-generator shafting system is designed and developed,which is applied to a domestic nuclear power turbine unit.