Abstract:

The processes of unit startingup and the high and medium pressure rotors bending accident were introduced. The vibration was measured on the site. The reasons of the bending accident of high and medium pressure rotors of turbine No.14 in a power generation company were analyzed. According to the preliminary judgment, the reasons of the bending accident of high and medium pressure rotors are that the mechanical properties of the high and medium pressure rotors are unstable, the local dynamic/static clearance is decreased due to long term operation of the unit, the control of the steam temperature and pressure in the steam sealing system is irrational, the rolling decision after tripping is incorrect, that is to roll the turbine as soon as the turbine shut down and do not turn the turbine sufficiently to release the bending caused by the heat stress, which is against the rule of the file ‘25 Key Requirements to Prevent Serious Accident in Power Production’， and so on.

Key words: high and medium pressure rotors, bend, mechanical properties, dynamic/static clearances