Trends and correlation analysis in diagnosing turbine rotor bow

Permanent rotor bow in a steam turbine is a serious failure which usually demands a time-consuming and costly repair. Its vibration-related symptoms are not specific and qualitative diagnosis typically has to employ results obtained during transients.In a 230 MW power steam turbine, gradual dynamic...

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Main Author: Tomasz GAŁKA
Format: Article
Language:English
Published: Silesian University of Technology 2009-01-01
Series:Transport Problems
Subjects:
Online Access:http://transportproblems.polsl.pl/pl/Archiwum/2009/zeszyt3/2009t4z3-1_05.pdf
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author Tomasz GAŁKA
author_facet Tomasz GAŁKA
author_sort Tomasz GAŁKA
collection DOAJ
description Permanent rotor bow in a steam turbine is a serious failure which usually demands a time-consuming and costly repair. Its vibration-related symptoms are not specific and qualitative diagnosis typically has to employ results obtained during transients.In a 230 MW power steam turbine, gradual dynamic behavior deterioration was observed, immediately after commissioning. Increase of the fundamental component of rear intermediate-pressure turbine bearing vertical vibration was detected, with the time constant of the order of months. Permanent rotor bow, exceeding 200 m, turned out to be the cause. Rotor repair resulted in a dramatic improvement of dynamic behavior, which, however, soon began to deteriorate again. Vibration spectra had been detected in the off-line mode since commissioning, which allowed to determine vibration time histories.Vibration trends analysis does not provide sufficient information to determine root cause, but allows for eliminating a number of possible malfunctions that give similar symptoms. In particular, the possibility of a sudden random-type damage due to human error is eliminated, which in fact is the most common cause of a permanent bow.Analysis of vibration amplitude correlation between vertical and axial directions reveals very strong correlation between fundamental components in the turbine under consideration, as well in the other one, in which similar failure has been observed. Third unit of the same type, apart from qualitatively different vibration trends, is characterized by correlation factors lower by a few times.This particular case is indicative of the importance of evolutionary symptoms (vibration amplitude time dependence and increase rate, as well as correlation factors) in qualitative diagnosis. Such symptoms can be very useful in distinguishing between possible failures which result in similar changes of machine vibration behavior.
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spelling doaj.art-94769b2e31d44aca8afeacfbabde84592022-12-22T00:41:12ZengSilesian University of TechnologyTransport Problems1896-05962009-01-0143 part 14351Trends and correlation analysis in diagnosing turbine rotor bowTomasz GAŁKAPermanent rotor bow in a steam turbine is a serious failure which usually demands a time-consuming and costly repair. Its vibration-related symptoms are not specific and qualitative diagnosis typically has to employ results obtained during transients.In a 230 MW power steam turbine, gradual dynamic behavior deterioration was observed, immediately after commissioning. Increase of the fundamental component of rear intermediate-pressure turbine bearing vertical vibration was detected, with the time constant of the order of months. Permanent rotor bow, exceeding 200 m, turned out to be the cause. Rotor repair resulted in a dramatic improvement of dynamic behavior, which, however, soon began to deteriorate again. Vibration spectra had been detected in the off-line mode since commissioning, which allowed to determine vibration time histories.Vibration trends analysis does not provide sufficient information to determine root cause, but allows for eliminating a number of possible malfunctions that give similar symptoms. In particular, the possibility of a sudden random-type damage due to human error is eliminated, which in fact is the most common cause of a permanent bow.Analysis of vibration amplitude correlation between vertical and axial directions reveals very strong correlation between fundamental components in the turbine under consideration, as well in the other one, in which similar failure has been observed. Third unit of the same type, apart from qualitatively different vibration trends, is characterized by correlation factors lower by a few times.This particular case is indicative of the importance of evolutionary symptoms (vibration amplitude time dependence and increase rate, as well as correlation factors) in qualitative diagnosis. Such symptoms can be very useful in distinguishing between possible failures which result in similar changes of machine vibration behavior.http://transportproblems.polsl.pl/pl/Archiwum/2009/zeszyt3/2009t4z3-1_05.pdfrotor bowsteam turbinemachine vibrationturbine-generator unit
spellingShingle Tomasz GAŁKA
Trends and correlation analysis in diagnosing turbine rotor bow
Transport Problems
rotor bow
steam turbine
machine vibration
turbine-generator unit
title Trends and correlation analysis in diagnosing turbine rotor bow
title_full Trends and correlation analysis in diagnosing turbine rotor bow
title_fullStr Trends and correlation analysis in diagnosing turbine rotor bow
title_full_unstemmed Trends and correlation analysis in diagnosing turbine rotor bow
title_short Trends and correlation analysis in diagnosing turbine rotor bow
title_sort trends and correlation analysis in diagnosing turbine rotor bow
topic rotor bow
steam turbine
machine vibration
turbine-generator unit
url http://transportproblems.polsl.pl/pl/Archiwum/2009/zeszyt3/2009t4z3-1_05.pdf
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