Diagnosis and numerical simulation of insulation ageing in generator stator

A numerical model is set up for calculation of the 3D stator temperature fields of a large hydro-generator using the theory of heat transfer. The corresponding boundary conditions are determined and the discrete representation of isoparametric element method with hexahedron and eight nodes is deduced. A SF300-48/1230 hydro-generator is taken as an example for calculation of the 3D stator temperature field with the insulation of strands taken into account, and the computed results agree with the measured results very well. Then the influence of shelling gap and different coefficient of heat conductivity on stator temperature field after stator insulation aging and shelling is analyzed by using numerical simulation method. Finally, the distribution of temperature field in the stator winding and iron core before/after insulation aging are presented to provide theoretical basis for real-time temperature monitoring and heat faults diagnosing of generator.