Study Of Vibration Problem Of A Large-scale Turbo-generator Stator End Winding Excited By Electromagnetic Force

Stability and reliability of stator end winding and its structure in a large turbo-generator can affect operating conditions. Winding vibration excited by electromagnetic force may lead to accidents.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 200MW large turbo-generator.The results obtained can provide theoretical basis for solving practical problems. The mainwork can be outlined as follow: 1. Based on Fourier expansion of current density, with separation of variablesmethod, we getexpressions of magnetic introduction intensity and formulas ofelectromagnetic force. Through numerical simulation, wecan find the lawof electromagnetic parameters varying andgive the locationwhere maximumelectromagnetic force occurs. 2. Through a model, which is used to study complex oscillation of the end winding, we obtain nonlinear magnetoelastic vibration equations with electromagnetic forceand friction force interaction. Meanwhile, we get double-direction vibration equations under electromagnetic force. 3. Fundamental resonance of one degree of freedom as well as two degrees offreedom is studied by multiple scales method. Through response equations,we analyzestability and bifurcation of the steady-state solution. The numerical resultsshow new phenomena of the system and point out the effect of current and friction coefficients on the system nonlinear behaviors. Besides, stabilitycriteria of combination resonance are established by analyzingthe double-direction vibrationequations. 4. Through a model of stiffened laminated composite conical shell, electromagnetic 6 第一章绪论vibration of whole end winding is studied.Expressions of electromagnetic forceand related elastic constants are derived. Generalized equations of inherent vibration as well as control equations are obtained by Galerkin integration and orthogonality of each mode.Through numerical calculation, we discuss the effect of support numbers and current value on vibration characteristics. 5. Based on elastic bent beam theory, magnetoelastic vibration equations of end collector ringof the statorare set up. Electromagnetic force in the equations isderived. Using analytic method and finite element method respectively, we discussinherent property of the collector ring in different restrictive conditions.Also,inherent property of diversion water pipe in different conditions is analyzed by finite element method. Also, conditions that avoid resonance are represented.