Three-dimensional finite element analysis of large electrical machine stator core faults

• Published in: IET electric power applications 2014-02, Vol.8 (2), p.60-67
• Main Authors: Ho, Choon W, Bertenshaw, David R, Smith, Alexander C, Chan, Trina, Sasic, Mladen
• Format: Article
• Language: English
• Subjects: Applied sciences; catastrophic failure; condition monitoring; condition‐monitoring sensors; cores; dimensional finite element models; Electrical engineering. Electrical power engineering; Electrical machines; electromagnetic behaviour; Exact sciences and technology; fault current distribution; fault signal; Faults; Finite element analysis; Finite element method; Insulation; inter‐laminar insulation faults; laminar constraints; large electrical machine stator core faults; machine windings; Mathematical analysis; Mathematical models; Miscellaneous; Position (location); sensing systems; sensitivity profiles; sensors; Stators; Three dimensional; three‐dimensional finite element analysis; winding insulation
• ISSN: 1751-8660; 1751-8679; 1751-8679
• DOI: 10.1049/iet-epa.2013.0065

Faults in the stator cores of large electrical machines can both damage local winding insulation and propagate to catastrophic failure. This study develops three-dimensional finite element models of inter-laminar insulation faults in order to obtain a deeper understanding of the electromagnetic behaviour of core faults and the sensitivity of sensing systems. The problem of developing a model that adequately reflects the laminar constraints of the structure, while remaining computable is addressed, together with eliminating images from boundaries. The model was validated by experimental measurement and results shown to be closely matched, with the fault current distribution also predicted. The sensitivity profiles for various fault positions and lengths were determined, which enables condition-monitoring sensors to be more specific about the location and true threat that a fault signal may pose to the machine.