Analysis and handling of bearing vibration of No.1 steam turbine-generator in Huarun Pengcheng Power Plant

The problem of high shaft vibration during generator rotor's 2nd critical speed and exciter rotor's 1st critical speed was always existed since the No.1 turbine-generator set was commissioned in 1996. The vibration affected the operation of load regulation seriously. Many efforts were made to try to solve the problem, but there was no result because of the complexity. By means of comparing the vibration mode with the dynamic balance tests, the root reason was found to be the bigger 2nd mode mass unbalance of the generator rotor which was caused by poor rotor dynamic balance quality in manufacturer. In an overhaul of the No.1 set in May 2004, a fine 2nd dynamic balance for the generator rotor was made after separating the exciter rotor from the generator rotor in field. Then the vibration was thoroughly settled.