Machinery Health
Keep the Boss Happy:
Look Inside a Turbine
Health
During Startup
Deane Horn
An automated monitor provides a live, continuous picture of exactly what
is happening inside a turbine for protection, prediction, performance
monitoring, and integration of the data with process control.
Machiner y
Process control brings a turbine, used to drive a boiler
feed pump, online after a hot outage. As load is
steadily applied, technicians maintain a close watch
on process parameters, vibration alarms and vibration plots
when, all of a sudden, the overall vibration begins climbing
abnormally.
The lube oil supply temperature is running cool, so the
techs bring up an orbit plot for deeper investigation. The
orbit plot is a little erratic, and phase is moving around (not
normal). Next, they pull up a live spectral plot for quick
confirmation of what they suspect is happening inside that
turbine. They’re not surprised to see a vibration peak at 0.48
times the turbine speed (see Figure 1).
Their monitoring equipment is unique because it allows
them to view different plots of transient data from the turbine as it is being brought up to operating speed. The live
data presentations yield real-time information that leads to
instant recognition of a developing problem before a “trip”
occurs. That knowledge might just prevent a catastrophic
failure.
Continuous online monitoring of essential turbomachinery represents technology well beyond vibration monitoring systems that provide only periodic snapshots of the
operation of a piece of equipment. The advanced architecture allows users to continuously view live, as well as record,
over 60 hours of data simultaneously from up to 32 sensors
for later retrieval and analysis.
This information can be critical for protecting the
turbine, predicting its future operation for maintenance or
repair planning, improving performance, and taking immediate action when necessary. This is a level of sophistication
never previously available from a single vibration monitoring system.
Field-based intelligence processes the vibration waveforms into useful frequency and amplitude content (FFT
spectral data). Preconfigured spectral parameter calculations
