Abstract:

Taking the warm startup failure of an S109FA gas steam combined cycle units made by an American company, GE, as an example, the reasons for temperature difference between top and bottom of high and middle pressure cylinder arranged in system is analyzed after the stop of the steam turbine. By shutting down, breaking the vacuum , stopping shaft seal and then close the high/middle pressure diverging valve, the temperature difference between top and bottom of high and middle pressure cylinder can be reduced, which can avoid the startup failure caused by upper and lower cylinder temperature difference.

Key words:

warm start, shaft vibration, high/medium pressure diverging valve, logical modification