Mechanical fatigue characteristics of high voltage generator insuration

This paper presents the deformation and fracture behaviors of stator windings subjected to static and repeated bending loads, and the reliability of newly developed insulation systems. The flexural deformation characteristics are revealed on the curved end portion of the stator windings for a 1300 MVA water cooled generator. The fatigue characteristics are examined on the test bar with three different kinds of the developed insulation systems. Comparing those results with thermal strain calculated, it has been confirmed that insulations have sufficient mechanical strength to endure thermal cycles in service.