Case 1 : Steam Turbine Vibration Issue

Location : Malaysia


The Plant combine cycle turbine has fully operated for about two years is comprises of dual gas turbine and single unit of steam turbine. The machine experience signification vibration on turbine bearing no.2. of its steam turbine unit which was observed from the online monitoring display. From the feedback of operation, unit reaching it critical on start-up condition and the vibration was amplified which almost to trip level (254um pp). On Friday 12th Aug 2016, a set of continuous measurement of 37.5MW steam turbine unit was conducted during unit full speed based load, staggered load, full speed no load and coast down. Methods of analysis include spectrum analysis, time waveform analysis, trend, orbital pattern and shaft centreline (SCL) movement. SCL’s calculation was performed based on input from latest inspection report by EPCC. All information on the bearing clearance are obtained and use during SCL analysis study. Results of data analyzed show that unit shaft vibration is above industry commissioning limit and not suitable for long-term operation with several issues.

Steam Turbine Power: 37.5MW