The Study Of Low-frequency Vibration Of Large Hydroelectric Stator

In recent years,with the increase of domestic hydropower installed capacity and the increase of stand-alone capacity,the stability of large hydro-generator sets has become the forefront of hydropower research.since 2007,the Three Gorges right bank,Longtan,Xiaowan,Laxiwa and a large number of large hydro-generating units have been put into operation,through the test found in these power plant unit stator base,core parts are varying degrees of low frequency vibration.at present,the general understanding of this low-frequency vibration is determined by the decision,the rotor is not round and eccentric caused by,but how to take effective measures to control,there is no quantitative technical solutions,it is necessary to carry out large hydroelectric power Machine stator low frequency vibration research,put forward a reasonable vibration control standard.Firstly,the finite element analysis method is used to calculate the unbalanced electromagnetic force of large hydroelectric generating units with Xiaowan power station as an example.The electromagnetic force of 100 Hz and 2.5Hz at different air gap length is calculated,and the influence of air gap deviation and roundness deviation on electromagnetic force is analyzed.Secondly,the finite element analysis method is used to simulate the effect of low frequency electromagnetic force on the stiffness and mode of stator structure.Combined with the basic principle of transient dynamics,from the perspective of low-frequency vibration generation mechanism,select a node of the stator structure,with 1-fold,2-fold and two frequency excitation and as excitation force to obtain the stator structure The response under each excitation force.Finally,combined with the time domain and frequency domain analysis of the data measured by the prototype of Xiaowan Hydropower Station,the relationship between the stator vibration and the unbalanced magnetic tension of the hydro turbine generator is determined by comparison with the numerical results.The relationship between the unbalanced magnetic tension and the distance between the unbalanced magnetic tension and the center of the air gap,eccentricity and the distance between the magnetic pole and the distance between the magnetic field and the distance between the magnetic field and the distance between the magnetic field and the center of the magnetic pole are calculated by using the mathematical tool MATLAB to calculate the unbalanced magnetic tension of the stator of Xiaowan Hydropower Station.Through the analysis of low frequency vibration of large hydroelectric generating units,the main causes of low frequency vibration are obtained.It is of great significance for the determination of the vibration standard of the existing operating units,which provides the theoretical basis and reference for the analysis and analysis of the vibration of the large hydroelectric generating units.It also has reference significance for the vibration analysis of other types of units.