Coupled Flexural and Torsional Vibrations Analysis of Turbine Generator Shaft Systems Caused by Asynchronous Juxtaposition

An increment transfer matrix method based on step-by-step integration method and traditional transfer matrix method was put forward.Combined with Riccati method,the increment transfer matrix method was used in a multi-mass model.And matrix equations calculating the responses of coupled flexural and torsional vibrations were deduced.The responses properties of coupled vibrations for 120° and 180°asynchronous juxtaposition of 200MW turbine-generator set were analyzed.The results show that the responses properties of flexural and torsional vibrations caused by 120asynchronous juxtaposition are similar to that of 180asynchronous juxtaposition.When the fault happened,Former two steps inherence frequencies and whirl speed frequency of torsion are excited.And the first step inherence frequencies of flexural vibration are also excited besides whirl speed frequency.Transient electromagnetism moment peak,torsional and torsional moment responses caused by 180asynchronous juxtaposition are lower than that of 120asynchronous juxtaposition.