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Evaluation of the degradation of generator stator ground wall insulation under multistresses aging / Zhidong, Jia in IEEE transactions on energy conversion, Vol. 23 n°2 (Juin 2008) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 23 n°2 (Juin 2008) . - pp. 474 - 483 Titre : Evaluation of the degradation of generator stator ground wall insulation under multistresses aging Type de document : texte imprimé Auteurs : Zhidong, Jia, Auteur ; Xiang, Peng, Auteur ; Zhicheng, Guan, Auteur Année de publication : 2008 Article en page(s) : pp. 474 - 483 Note générale : Energy conversion Langues : Anglais (eng) Mots-clés : Weibull  distribution;  ageing;  electric  breakdown;  electric  generators;  machine  insulation Résumé : The actual stator bars of an 18 kV/300 MW generator were used for accelerated multistress aging tests to investigate the degradation of ground insulation. An aging system with combined stresses including thermal, electrical, mechanical vibration, and thermomechanical factors was used to test the aging of stator bar specimens. The nondestructive parameters including partial discharge (PD) quantities and dissipation factor parameters were measured during aging test in order to evaluate the degradation of stator ground wall insulation. At the end of the aging test, an AC breakdown test was performed on the bars in order to obtain the remaining breakdown voltage (BDV) after their nondestructive data had been measured. The changes of nondestructive parameters indicated that the degradation of ground wall insulation. For example, the changes of skewness of indicated the shape of voids in ground insulation changes from flat to narrow, and even exhibits treeing, which is dangerous to insulation because it shortens the effective distance of insulation between high voltage and the ground. The results obtained are summarized as follows. The BDV data fit a Weibull distribution. The correlation between the dissipation factor, the PD parameters, and the breakdown voltage were analyzed, among which the skewness of the average discharge had the most correlation with breakdown voltage. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4505392&sortType%3Das [...] [article] Evaluation of the degradation of generator stator ground wall insulation under multistresses aging [texte imprimé] / Zhidong, Jia, Auteur ; Xiang, Peng, Auteur ; Zhicheng, Guan, Auteur . - 2008 . - pp. 474 - 483. Energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 23 n°2 (Juin 2008) . - pp. 474 - 483 Mots-clés : Weibull  distribution;  ageing;  electric  breakdown;  electric  generators;  machine  insulation Résumé : The actual stator bars of an 18 kV/300 MW generator were used for accelerated multistress aging tests to investigate the degradation of ground insulation. An aging system with combined stresses including thermal, electrical, mechanical vibration, and thermomechanical factors was used to test the aging of stator bar specimens. The nondestructive parameters including partial discharge (PD) quantities and dissipation factor parameters were measured during aging test in order to evaluate the degradation of stator ground wall insulation. At the end of the aging test, an AC breakdown test was performed on the bars in order to obtain the remaining breakdown voltage (BDV) after their nondestructive data had been measured. The changes of nondestructive parameters indicated that the degradation of ground wall insulation. For example, the changes of skewness of indicated the shape of voids in ground insulation changes from flat to narrow, and even exhibits treeing, which is dangerous to insulation because it shortens the effective distance of insulation between high voltage and the ground. The results obtained are summarized as follows. The BDV data fit a Weibull distribution. The correlation between the dissipation factor, the PD parameters, and the breakdown voltage were analyzed, among which the skewness of the average discharge had the most correlation with breakdown voltage. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4505392&sortType%3Das [...]