Steam Turbine Rotor Eccentricity Problem

Probably due to rapid load swings that resulted in uncontrolled differential contraction/expansion of the rotor and turbine. The misoperation of the LP heaters may have made the problem worse. Although your eccentricity was within limits, you may have exceeded the turbine's design eccentricity rate of change; i.e., you did not allow the proper amount of time to ramp up the loading.

If the vibration continues and/or increases, it may be necessary to take the unit out of service (properly) and do an internal inspection to see if there was any rubbing between the blades and the shroud/casing, as well as the generator rotor and stator.

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It appears that after the initial event it may have been better to restart the sequence after you had determined the reason first. By running your turbine, you may of brought yourself to this situation.

your turbine ran down from 50 to 1.9MW, meaning internal pressures were suddenly reduced. You may have had condensate from heaters return to turbine causing some rotor distortion. Your eccentricity came down after closing htrs . Hts may have stuck open non return valves. Check all drn returns to casing.