Mechanical Fatigue Characteristics of High Voltage Generator Insulation

This paper presents the deformation and fracture behavior of stator windings subjected to static and cyclic bending loadings, 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 bars with three different kinds of the developed insulation systems. Comparing those results with calculated thermal strain, it has been confirmed that the insulation systems have sufficient mechanical strength to withstand thermal cycling in service.