Magnetic-solid coupling nonlinear vibration of generator set stator system 1 Qiu Jiajun Li Wenlan School of Mechanical Engineering, Tianjin University, Tianjin Plus 0072 Stator double-shell system Mountain 4+25, 8 o'clock magnetic-coupling double resonance. The obtained amplitude-frequency response equation is numerically calculated. The results show that the maximum amplitude of each mode is reduced compared with the relative steady-state operation. This is different from the vibration law of the generator rotor shaft system.
The two-phase short circuit is a relatively common species in the asymmetric operation state of the generator set, and a large inrush current is generated at this time. When the two-phase short circuit occurs, the vibration of the turbine generator shaft shaft system is significantly intensified compared with the rated normal operation state. Based on the actual project of the Xiaoxia Project, this paper analyzes the magnetic-solid coupling nonlinear vibration of the stator system in the two-phase short circuit for the strong model of the 24th hydroelectric generating unit and the double-shell system.
1The mathematical model of the nonlinear vibration of the magneto-coupling of the stator system. The electromagnetic force of the inner surface of the stator core during the two-phase short-circuit is the magnetic-solid coupling nonlinear vibration equation of the stator double-shell model, which is the factory, which is the vibration component of the stator double-shell model. The heart is the inner diameter of the stator core, and the pair is the generalized mass of the inner casing of the stator, which is the first mode shape of the radial vibration of the stator core.
2 Stator system magnetic-solid coupling double resonance When considering the interaction between the stator core radial vibration displacement and the air gap magnetic field, the electromagnetic force acting on the inner surface of the stator core contains the nonlinear component of the vibration displacement, and Equation 1 is the nonlinear vibration. equation. As long as the electromagnetic force acting on the inner surface of the stator core is given, the nonlinear vibration equation of the magneto-coupling of the stator system in the corresponding operating state is obtained. The multi-scale method is used to analyze the magnetic-solid coupling double resonance of the stator system under the combined action of the parametric excitations at 4+206,88, and the steady-state equation is obtained. Through analysis, the steady-state equation has two solutions, namely the amplitude of the fourth-order mode and the eighth-order mode. Either zero at the same time or neither zero. When 6 is simultaneously zero, only the eighth-order mode is excited, and the solution of the steady-state equation is strongly correlated with resonance, which is discussed in detail in Table 3. When 4. is not zero, the mode is stimulated at the same time, and the solution of the amplitude-frequency response equation is 1 national 973 key basic research plan project, 99802039 special funds are funded, 2 is the coefficient of the equation, by power generation The electromagnetic parameters of the machine and the structural parameters of the double-shell system are determined. 3 Calculation results analysis The numerical solution of the equations is carried out, and the frequency response curves of the various modes participating in the double resonance in the corresponding operating state are obtained.
1 is the frequency response curve of each mode in the relative steady state operation. 2 is the frequency response curve of each mode mode when the positive and negative sequence currents are maximum when the two phases are short-circuited. The resonance interval of the two-phase short circuit and the maximum amplitude of each mode are reduced compared with the relative steady state operation state, which is related to the vibration of the hydro-generator rotor shaft system given in Document 1. The rules are different.
4 Conclusion There are two solutions to the double resonance of the stator system in the case of two-phase short circuit, and the maximum amplitude of the resonance interval and the various modes participating in the resonance are reduced compared with the relative steady state operation state, and the power generation is The vibration law of the rotor shaft system is different.
1 Chen Guiqing, Qiu Jiajun. Parametric strong resonance of large hydro-generator units during asymmetric operation. Huang Huai Academic Journal, 1999, 522 Qiu Jiajun, Li Wenlan. The influence of boundary constraints on the solid and frequency of the hydro-generator stator system. Large motor technology, 998, 13725
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