Steam Turbine High Vibration Issue During Startup

Hello Guys
We performed major inspection of Harbin made Steam Turbine of 110 MW that runs on the steam of HRSG as our plant is a CCPP.
We replaced LP&HP rear and front glands seals and also replaced the all gland seals of LP diaphragms and some seals of HP diaphragms.

Some measures were also taken to corrective the alignment.

Startup of Steam Turbine was initiated after 30 hours of turning and put it on rolling but on around 600 RPM, the vibration of Brg – 3 X approached to 160 micron (254 micron is the trip value) and vibration of all other bearings also increased except generator bearings. Eccentricity also approached to 110 microns.

Machine was coasted down to 60 RPM and all vibration parameters became normal.

Machine was again ramped up and stopped around 400 − 460 RPM but after some time vibration of Brg – 1&2 increased. Speed of the machine was decreased to reduce the vibration values.

Machine was again ramped up but the machine tripped on Bearing – 2 high vibration around 900 RPM.

Machine was then rolled around 200 to 600 RPMs however today in the morning HP differential expansion approached to 5 mm (alarm is 6.5 mm) and machine was brought to turning speed however eccentricity values were still increasing.

Layout of the Steam Turbine and HMI screenshots during startup are attached.

Could you please help out what could be the possible reasons and what should be our way out.