We have GE twin shaft gas turbine (MS3002) with second stage variable nozzles and equipped with Speedtronic MK-II control system.
GT under went HGPI (hot gas path inspection) on Nov, 2018 and right after aforesaid maintenance, its LP shaft radial vibration and Brg#4 side casing seismic increased from 1 mm/sec to 8 mm/sec. Due to above issue we have to compromise load and consequently unit runs at lesser LP speed. Could anyone please suggest what has go wrong and cause of rise in LP shaft seismic vibration as during HGPI, maintenance done on HP rotor, combustion inspection and fuel nozzle and NOT LP SHAFT and FIELD INSTRUMENTATION.
Further, I have shared operating parameters on various dates before and after HGPI maintenance for review and confirm parameters are appropriate or otherwise.
Meanwhile, we have checked undermentioned.
1. GCV, SRV and NCV stroke checking and found appropriate.
2. HP speed settings check and found as per Control specs.
3. PCD TX range, calibration found as per recommended settings.
4. Second stage Variable Nozzle operation / stroke check which is smooth (-5 Deg to 15 deg)
5. P2 pressure calibration checked and found appropriate.
6. LP and HP speed pickups checking.
7. Temperature and nozzle control settings verified.
8. Dry-run test for unit startup sequence complete simulation, which is normal.
Looking forward affirmative response as usual and we would welcome in case of any query.
Regards,
Haroon
GT under went HGPI (hot gas path inspection) on Nov, 2018 and right after aforesaid maintenance, its LP shaft radial vibration and Brg#4 side casing seismic increased from 1 mm/sec to 8 mm/sec. Due to above issue we have to compromise load and consequently unit runs at lesser LP speed. Could anyone please suggest what has go wrong and cause of rise in LP shaft seismic vibration as during HGPI, maintenance done on HP rotor, combustion inspection and fuel nozzle and NOT LP SHAFT and FIELD INSTRUMENTATION.
Further, I have shared operating parameters on various dates before and after HGPI maintenance for review and confirm parameters are appropriate or otherwise.
Meanwhile, we have checked undermentioned.
1. GCV, SRV and NCV stroke checking and found appropriate.
2. HP speed settings check and found as per Control specs.
3. PCD TX range, calibration found as per recommended settings.
4. Second stage Variable Nozzle operation / stroke check which is smooth (-5 Deg to 15 deg)
5. P2 pressure calibration checked and found appropriate.
6. LP and HP speed pickups checking.
7. Temperature and nozzle control settings verified.
8. Dry-run test for unit startup sequence complete simulation, which is normal.
Looking forward affirmative response as usual and we would welcome in case of any query.
Regards,
Haroon
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