Large-scale 3D electromagnetic field analysis for estimation of stator end region loss in turbine generators

In indirectly hydrogen cooled turbine generators used in high-efficiency combined cycle power plants, improving the energy efficiency and increasing the power density are required for one of the solutions of the global environmental problems. When the output current is increased for achieving the high power density, the stray load loss at the stator end region is increased by the leakage flux from the armature and field coils. Therefore, in the case that the stray load loss at the stator end region is increased when the output capacity is increased, it is necessary to evaluate the temperature under the condition of the leading power factor load. In this paper, we analyzed the loss density distribution at the end region structures using the large-scale 3D electromagnetic field analysis to establish the temperature reliability in the 870MVA indirectly hydrogen cooled machine, which is the largest class capacity in the world. Using the loss density distribution obtained by the analysis, the thermal analysis is then performed. The analysis results show good agreements with the measured values.