Numerical calculation of end region electromagnetic field of large air-cooled turbogenerator

The objective of this paper is to solve the problems in the calculation of electromagnetic field in the end region of a large air-cooled turbo-generator. Firstly, a mathematic model used for the calculation of electromagnetic field in the end region of large air-cooled turbo-generators is presented. The solved region in full model, combining the end zone with the stepped stator core, is extended to the stator and rotor core. The spatial locations of end structures, the actual shape of the stator and rotor end windings as well as their influence on the calculation of the end zone field are considered accurately. With the combination of 2D and 3D magnetic field method, the boundary condition is determined. Taking QF-150-2 air-cooled turbo-generator as an example, the end field, including effects of the eddy current, is calculated under no-load and full load conditions. The reliability of the method presented in this paper is verified.