The Hydraulic Influence On The Main Shaft System Stability Of Turbine Generator

With the development of economy, we need more electrical energy, andhydroelectric power has gradually aroused our attention. But the stability problem of ithaunts the people. Especially turbine generator unit shaft influenced by high water head,large flow and powerful electromagnetic field, and the law is not clear. Therefore, it isvery necessary to study the stability of turbine generator unit shaft system.The finite element method and transfer matrix method are used to calculate thenatural frequency and prove the correctness of the results. The influence of additionalwater mass, electromagnetic stiffness and gyroscopic effect on natural frequency isstudied. The results show that: the gyroscopic effect is the main influence factor, theelectromagnetic stiffness is secondly, additional water quality is the minimum. All thefactors are worthy of attention.The influence of hydraulic impact, electromagnetic force and initial conditions isstudied. The results show that: the influence of additional water mass on the vibration isnot very significant. When the vibration is stable，the amplitudes of generator rotor andturbine runner are similar and the amplitude of the turbine runner is slightly big. Theamplitude of frame is far smaller, and the extreme of their speeds are similar. Liftingphenomenon and b10are the main factors, the increasing of them will accelerate declineof frame’s speed. Frame’s speed changes the fastest, and runner’s speed ranks second,and rotor’s speed changes the slowest. The instantaneous impact which is given to therotor causes the biggest influence, which is given to the frame causes the least influence.The extreme speed of the runner is many times more than others. Rise of11can causeamplitude decline. Rise of21has the same effect, but11is more obvious than21.Rise of21increases the number of vibration before curve monotonically decreasing inthe time domain and narrows the resonance zone width in the curve of amplitude-frequency; In the curves of amplitude-frequency, the extreme of resonance proportionallyreduces with f1decreasing, the decline of f1also narrow resonance zone width.Figure50; Table5; Reference54...