Significance of Defects Inside In-Service Aged Winding Insulation

Christof Sumereder, Tilman Weiers

Publikation: Beitrag in einer FachzeitschriftArtikelBegutachtung

Abstract

This study aims to gain insight into the consequences of local defects in stator winding insulation; therefore, optical (microscopic) inspections and voltage-endurance tests have been carried out on in-service aged generator bars. In this context, generator bars with mica-bitumen insulations and generator bars with mica-epoxy insulations were investigated. The mica-bitumen insulations had been in service for 43 years in a 12 kV hydro-generator. The generator bars with mica-epoxy insulation had been dismantled from two identically constructed 10.5-kV generators after 35 and 36 years of service. The time to breakdown values obtained from the voltage-endurance tests were evaluated using a Weibull distribution. Apart from the scale parameter, Weibull exponent of this distribution allowed for the identification of early failures. The voltage-endurance tests carried out on replacement bars for these generators did not yield any early failures; such failures, however, were detected on both types of the in-service aged insulations. In particular, these occurred at high levels of electric stress and at delaminations between the copper conductor and the groundwall insulation. It is concluded that the interpretation of the measured time to breakdown values and their scatter depends on the level of electric stress.
Originalspracheenglisch
Seiten (von - bis)9-14
FachzeitschriftIEEE Transactions on Energy Conversion
Jahrgang23
Ausgabenummer1
DOIs
PublikationsstatusVeröffentlicht - 2008

Fingerprint

Untersuchen Sie die Forschungsthemen von „Significance of Defects Inside In-Service Aged Winding Insulation“. Zusammen bilden sie einen einzigartigen Fingerprint.
  • Zustandsbewertung von Betriebsmittel in elektrischen Netzen

    Muhr, H. M. (Teilnehmer (Co-Investigator)) & Sumereder, C. (Projektleiter (Principal Investigator))

    1/01/0231/07/15

    Projekt: Arbeitsgebiet

  • Hochspannungstechnik

    Sumereder, C. (Teilnehmer (Co-Investigator)), Schwarz, R. (Teilnehmer (Co-Investigator)), Woschitz, R. (Teilnehmer (Co-Investigator)), Pack, S. (Teilnehmer (Co-Investigator)), Lick, W. (Teilnehmer (Co-Investigator)), Muhr, H. M. (Teilnehmer (Co-Investigator)), Eberhardt, R. (Teilnehmer (Co-Investigator)), Steyn, D. (Teilnehmer (Co-Investigator)), Judendorfer, T. (Teilnehmer (Co-Investigator)), Jaufer, S. (Teilnehmer (Co-Investigator)) & Fabian, J. (Teilnehmer (Co-Investigator))

    1/01/9531/12/24

    Projekt: Forschungsprojekt

  • Hochspannungsisolierstoffe und -systeme

    Muhr, H. M. (Teilnehmer (Co-Investigator)), Woschitz, R. (Teilnehmer (Co-Investigator)) & Sumereder, C. (Teilnehmer (Co-Investigator))

    1/01/9531/12/24

    Projekt: Arbeitsgebiet

Dieses zitieren