Synchronous generators play a vital role in power systems. One of the major mechanical
faults in synchronous generators is related to bearings. The popular vibration
analysis method has been utilized to detect bearing faults for years. However, bearing
health monitoring based on vibration analysis is expensive. One of the reasons
is because vibration analysis requires costly vibration sensors and the extra costs
associated with its proper installation and maintenance. This limitation prevents
continuous bearing condition monitoring, which gives better performance for rolling
element bearing fault detection, compared to the periodic monitoring method that
is a typical practice for bearing maintenance in industry. Therefore, a cost effective
alternative is necessary. In this study, a sensorless bearing fault detection method
for synchronous generators is proposed based on the analysis of electrical signatures,
and its bearing fault detection capability is demonstrated.
Experiments with staged bearing faults are conducted to validate the effectiveness
of the proposed fault detection method. First, a generator test bed with an in-
situ bearing damage device is designed and built. Next, multiple bearing damage
experiments are carried out in two vastly different operating conditions in order to
obtain statistically significant results. During each experiment, artificially induced
bearing current causes accelerated damage to the front bearing of the generator.
This in-situ bearing damage process entirely eliminates the necessity of disassembly and reassembly of the experimental setup that causes armature spectral distortions.
The electrical fault indicator is computed based on stator voltage signatures
without the knowledge of machine and bearing specific parameters. Experimental
results are compared using the electrical indicator and a vibration indicator that is
calculated based on measured vibration data. The results indicate that the electrical
indicator can be used to analyze health degradation of rolling element bearings in
synchronous generators in most instances. Though the vibration indicator enables
early bearing fault detection, it is found that the electrical fault indicator is also
capable of detecting bearing faults well before catastrophic bearing failure.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1145 |
| Date | 15 May 2009 |
| Creators | Choi, Jae-Won |
| Contributors | Parlos, Alexander G. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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