Analysis and Processing on Shaft Displacement Migration in 330-MW Steam Turbines

The steam turbine shaft displacement protection device can precisely reflect the working condition of thrust bearings. The gradual increasing axial displacement is observed frequently after the heating transformation was carried out in Turbine 3 of one power plant, and its variation is inconsistent with the temperature variation of thrust shoe. Through disassembling the thrust shoe and careful inspection, it is discovered that the thrust shoe is not in parallel with the thrust collar, which causes the increasing axial displacement during unit operation. Then the thrust tile repairing technology is modified and the thermal measurement points are adjusted. After such maintenance, the axial displacement is restored to the ex-factory value and the unit keeps running in a stable state.