9 Minutes of Knowledge - Issue 4 - Vibration Analysis November 2022 - Page 5
TOPIC : Reg - Steam Turbine Vibration
Dear All ,
During our plant shutdown we opened Steam Turbine casing & checked the rotor & condition was good & there was no abnormalities observed in the rotor . After start up the machine behavior was different & Steam Turbine Vibrations NDE Vibrations were maintaining high & Its goes down to minimum 1.1 mils also at certain time intervals approx . for every 2 hours at same speed & then increases to 2.5 mils . This happening in both the probes at NDE side & DE side vibrations were normal ..
The below trend showing Turbine NDE ( 16VT-3447-8 & 16 ) & DE ( 16VT-3447-7 & 15 ) Vibration trend . We checked all process parameters like Steam Temp , Pressure , Flow , Vacuum , Lube oil Temp , Pressure & we are not getting any deviation in process parameters & also 10 degree phase change observed , 1X dominant , Circular orbit , No glitches observed , no rubbing indication observed . Please suggest from your end by seeing below plots .
Turbine NDE means exhaust end ? What is the configuration of this steam turbine ? Turbine NDE end connected with any compressor or generator ? Any gear coupling between the turbine and compressor / generator ? What maintenance activities were done ?
1 . Turbine NDE- Steam entry side ., 2 . Probe Location X & Y 45 degree from K phaser 3 . Turbine DE connected with Compressor . 4 Its Gear coupling . 5 . No Maintenance carried out in Steam Turbine area .
If any carbon deposition near labyrinth area may cause 1X . Need to check !
Good day , is the turbine and compressor at operation temp ? I had a similar trend and it was crabbing and at operating temps it stabled out .