REDUCED-ORDER SHAFT SYSTEM MODELS OF TURBOGENERATORS

Two very simple, sufficiently accurate reduced-order shaft system mode ls-Truncated Modal model and Aggregated Mass Model-used in turbogenera tor torsional oscillation analysis are presented in this paper. The fi rst is developed by taking the exact duplicate of the transient behavi or of the original as far as the low-order modes are concerned. While the second is established by fitting the low-order mode shapes of the original. They can be implemented into the existing programs without a ny difficulty, while the fidelity of which can easily be adjusted by c hanging their orders.