[1F4] Data analysis and fault-finding case study of a 660 MW steam turbine generator set in a power station
Z Malik
EDF Energy, UK
TG2 is a GE 660 MW steam turbine generator unit at Hartlepool power station in North East England. The unit consists of a high-pressure (HP) turbine, an intermediate-pressure (IP) turbine and three low-pressure (LP) turbines coupled with an alternator and an exciter. Although the unit was previously operating normally and within the established ISO standards, recent reports indicated excessive loading on the barring gear and instances of the barring gear becoming stuck.
EDF Energy's central technical organisation conducted a comprehensive analysis of the vibration data, including online, barring, run-up and run-down data, to determine the root cause of the overloading. Data analysis revealed that the generator non-drive end (NDE) bearing (bearing 12) showed signs of tilting, reducing the clearance between the shaft and the bearing and causing friction. This friction was determined to be the cause of the overloading of the barring gear. The generator operates in a pressurised hydrogen environment and changes in pressure during operation and shutdown had a ratcheting effect on the bearing tilt and clearance reduction. The EDF Energy engineering team responded promptly and professionally, documenting the issue, raising awareness among operations and implementing a recovery plan.
EDF Energy's central technical organisation conducted a comprehensive analysis of the vibration data, including online, barring, run-up and run-down data, to determine the root cause of the overloading. Data analysis revealed that the generator non-drive end (NDE) bearing (bearing 12) showed signs of tilting, reducing the clearance between the shaft and the bearing and causing friction. This friction was determined to be the cause of the overloading of the barring gear. The generator operates in a pressurised hydrogen environment and changes in pressure during operation and shutdown had a ratcheting effect on the bearing tilt and clearance reduction. The EDF Energy engineering team responded promptly and professionally, documenting the issue, raising awareness among operations and implementing a recovery plan.
