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Recently our GT (67.5MW) tripped of grid disturbance (hand tripped). There are 2 GBCs in service (each supporting individual gts). GBC is centrifugal type (2BCL 408) 2.5MW motor capacity, 17750 m3/Hr gas handling capacity machine. on Tripping 2 GBCs tripped. While starting it was not possible to bring them into service after 2 or three startups. Because there was high vibration alarms only at High speed shaft of gear box. On inspection the active thrust pads of high speed shaft were found damaged, in addition to thrust collar metal loss (on both machines). Is there any chances of Antisurge valve malfunctioning? surprisingly there was no damages in the thrust pads of HP, LP compressor bearings.
what would be the probable cause/how to avert such incident in future? Following points may also be kept in mind. During tripping the 24V dc support was not there. possible oil starvation (gravity feed) during coasting down.
what would be the probable cause/how to avert such incident in future? Following points may also be kept in mind. During tripping the 24V dc support was not there. possible oil starvation (gravity feed) during coasting down.
