The Analysis On Response Of Torsion Vibration For Turbo-generators Shafts With Power Network Impact

With the development of electric power, the problem of shaft Torsional Vibration on turbine generators has drawn broad attention. Power system fault and operating mode changes may have a greater impact on the power network. These conditions may result in shaft torsional vibration. So it is greatly practical and significant for safe and stable operation units to analyze the response characteristics of torsional vibration with power network impact.Taking an example of torsional vibration simulator on DongFang 300MW turbine generators, the multi-spring mass model of whose shaft is established. Then the inherent characteristics of shaft torsional vibraion are calculated by algorithm of improved Riccati traditional matrix and by that of Holzer. These tesults are consistent with the test results.A new method of Riccati traditional matrix combined with Newmark-βincremental method is put forward to solving shaft response of nonlinear torsional vibration system. But there will be a linear suppose in the time-step when using this method, a method is proposed to eliminate cumulate error from this suppose. Then another model for response of torsional vibration is established. On this model, the response characteristics of shaft torsional vibration are calculated and analyzed under several typical impacts of power network. Thus, we can conclude that from this paper, the response characteristics can be described as following: all these impacts can stimulate inherent frequencies on different degrees; for the whole shaft, the responses of low pressure cylinder rotor and of generator rotor are stronger, especially of generator rotor; the same section of shaft have different response to different impacts, so we can not simply to determine which impacts will cause a stronger response and should analyze problems depending on the actual situation.Torional electromechanical systems is composed of mechanic,electric and network. Submodels of every part are introduced in this paper, then the Model unified electric and mechanic is set up. On the EMTP-RV (which is an electro -magnetic transient simulation software), the typical power network impacts are simulated, and the response of shaft torsional vibration are gained again. The response results are consistent with above results used the new method. It provides a reference for further research on the actual units.