Abstract: Aiming at the faults of large vibration amplitude and high bearing shell temperature in the inadequate valve management programs of 600-MW steam turbines, the frequency spectrum of the excitation force of one regulating stage blade is calculated with Matlab and compared with the natural frequency of the high-pressure rotor in different valve management programs. Then the bearing dynamic characteristics are calculated with Matlab programs in different valve management programs and input into Ansys. Finally, the stability indices of different valve management programs are obtained and the optimal valve management program is determined. Based on the above results, two improved regulating stage admission structures corresponding to fixed and unfixed peak regulation ranges are put forward, which provides a new thought for the design and manufacture of new units and for the flow path retrofit of the old ones.

Key words: steam turbine, valve management program, excitation force, shafting stability, regulating stage admission structure