Vibration Characteristics And Structural Analysis Of End Winding On Large Turbogenerator Stator

The vibration of turbogenerator in the running process may have negative impact on the service life.If it takes place resonance or high level vibration amplitudes under double working frequency electromagnetic forces,it may result in structural damage and other serious consequences.So the natural frequencies of certain mode shape need to avoid the resonance frequencies region and the vibration amplitudes of end winding under rated load electromagnetic forces need less than the specified value in the design stage.So it is important to study the vibration problems so as to provide more reasonable designing basis for projects.This thesis makes researches on a 600 MW large turbo-generator.The results obtained can provide theoretical basis for solving practical problems.The structural optimization schemes has extremely important theoretical significance and practical engineering value.The main work can be outlined as follow:First of all,through a model of stiffened laminated composite conical shell,natural vibration of whole end winding is studied.Expressions of related elastic constants are derived.Generalized equations of inherent vibration are obtained by Galerkin integration.Through numerical calculation,we discuss the effect of support numbers on natural vibration characteristics.Second,a three-dimensional fine finite element model of the stator end winding,which consists of all the structural components and connection details among them,is set up by means of ABAQUS/CAE.The lower orders of natural frequencies and modes are analyzed by means of the obtained three-dimensional numerical models.The finite element model and simulation method are validated by the consistence of the numerically determined natural frequencies corresponding to the modes with elliptic shape with those measured by the modal test.With the finite element model,parametric study on the natural frequencies and modes of the end winding is performed.At last,based on the objectives of the natural frequencies corresponding to elliptic modes avoiding the resonance frequencies region,the structural optimization schemes of end winding are investigated incorporation with the results of parametric study on the natural vibration characteristics.