Volume 8, Issue 6, November 2019, Page: 145-151
Characteristics of Indicators for Insulation Deterioration in 26 kV Generator Stator Windings
Soo-hoh Lee, Power Generation Laboratory, Korea Electric Power Corporation (KEPCO) Research Institute, Dae-jeon, South Korea
Hee-dong Kim, Power Generation Laboratory, Korea Electric Power Corporation (KEPCO) Research Institute, Dae-jeon, South Korea
Tae-sik Kong, Power Generation Laboratory, Korea Electric Power Corporation (KEPCO) Research Institute, Dae-jeon, South Korea
Received: Sep. 23, 2019;       Accepted: Oct. 16, 2019;       Published: Nov. 4, 2019
DOI: 10.11648/j.epes.20190806.11      View  12      Downloads  5
Abstract
This study conducted and analyzed the results of non-destructive tests (AC current, dissipation factor, and partial discharge tests) and a destructive test (overvoltage test) on 26 kV-generator stator windings with a ground fault. The target generator was a steam turbine generator in operation for over 30 years, and ground fault in windings occurred because of the rapid and instantaneous temperature rise in the copper conductor owing to the partial loss of generator cooling water. By comparing the non-destructive test data measured during the planned preventive maintenance period two years before the ground fault and the data gathered just after the ground fault, the study conducted an in-depth analysis of the effect of moisture on insulation diagnosis factors. If both the dissipation factor and capacitance data increased when compared to those of previously estimated values at same applied AC voltage level, it represented that the insulation materials absorbed moisture. Moreover, it was further developed that both of the dissipation factor and capacitance surge voltage were detected when the discharge started whereas the concerned surge voltage for AC current was detected when the discharge was proceeded in some extent. It is expected that a wider understanding of insulation diagnosis factors developed from this study will contribute not only to a more reliable diagnosis data analysis but also a stable power supply by preventing accidents in advance.
Keywords
Insulation, Stator Winding, Generator, AC Current, Dissipation Factor, Capacitance, Partial Discharge, Overvoltage
To cite this article
Soo-hoh Lee, Hee-dong Kim, Tae-sik Kong, Characteristics of Indicators for Insulation Deterioration in 26 kV Generator Stator Windings, American Journal of Electrical Power and Energy Systems. Vol. 8, No. 6, 2019, pp. 145-151. doi: 10.11648/j.epes.20190806.11
Copyright
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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