Turbogroup analysis and diagnosis service PRE-7028
Turbomachinery requires special multi-channel equipment to record in parallel the vibration of the sensors installed on the machine.
The start-up of a turbo-alternator group (gas or steam turbine) is a transient operation that involves risk, but at the same time provides much more significant information on operating condition than what is possible to obtain in steady state.
The structural characteristics of flexible shaft rotors and the operating conditions of the unit in terms of temperature, differential expansion, eccentricity compensation, residual unbalance, grid connection, load rise, etc., pose a serious threat to the turbomachinery dynamics if there is no capacity to monitor critical variables during unit start-up.
The turbo-alternator run-in control allows to visualize in real time the vibration vectors during the run-up or coast-down, knowing in a quantitative and qualitative way its dynamic behavior to predict if it will be able to overcome the critical ones without incurring in risks of damaging bearings, steam seals and other components.
The transient recording of the vibratory signals allows characterizing the rotor dynamics at different RPM conditions (critical frequencies) and operating load (level variations), and establishing the baseline as a reference of the mechanical condition in terms of hysteresis at critical frequency steps, spectral analysis, orbital analysis, hydrodynamic lift, etc.
Run-in control and transient recording is performed simultaneously thanks to the high data processing and real-time display capabilities of PC-based systems:
- Connection of the data acquisition unit to the buffer outputs of the machine protection racks. “Retroffitting of the existing sensors on the machine.
- Temporary placement of additional probes (ICP, Eddy, …) at the most representative points of the machine (pedestals and housings), and connection to the data acquisition unit.
- Turbo-alternator launch, monitoring and data logging during acceleration ramp, critical pass through, speed and timing, grid coupling and load ramp up to steady state.
- Ramp control according to foreseeable vibration levels over critical levels, group triggering or controlled passage depending on the case.
- Validation of existing probes (GAP, noise, …), determination of warning and danger levels of the protection racks, as well as their multiplication factors at each critical step (“treshold multiplier”).
For more information, please contact Preditec’s sales department.
