A customer operating a biomass fired powerplant contacted Maintenance Partners about a vibration alarm that was generated by the steam turbine control system.
Initial Data Analysis
The initial analysis of the data trends provided showed that the vibration was generated inside the steam turbine – possibly caused by friction.
Any contacts between rotor and stator (even if initially small) create local heating spots by friction.
These heating spots initiate a deformation of the shaft and as a consequence a residual unbalance, which further increases the heating.
This is called the Newkirk phenomenon is auto-amplifying and eventually leads to the trip of a turbine. A detailed vibrational analysis can be used to identify this phenomenon.
Detailed Vibration Analysis
By studying the Nyquist diagrams, the vibrational specialists of Maintenance Partners were able to locate the origin of the problems and could validate the necessity to open the turbine.
The inspection of the steam turbine confirmed that oil mist particles had entered the first labyrinth of the gland steam stuffing box. The oil mist particles had carbonized, creating contact points.
Maintenance Partners installed an online vibrational monitoring device, connected to a remote connection. Specialists from MP Belgium and France then joined in efforts for remote diagnosis.
A team of technicians then opened the turbine and clearly identified the problem.
First analysis on Friday and turbine opened on Wednesday !
After the inspection, the rotor was sent to Maintenance Partners’ Rotorshop for repair and balancing.
For more information about our remote monitoring solutions for steam turbine generator sets, please visit this page.
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