Parametric Study for the Design of the End Region of Large Synchronous Generators Based on Three-Dimensional Transient Finite Element Analysis

Large synchronous generators are a major source of electrical energy in a power system and the efficiency and reliability are important indices of their performance. As the capacity of large generators increases, the eddy current losses in the end components also rise due to the end leakage fluxes produced by the armature and field end windings. Suppressing the eddy current losses and the resultant temperature rise in the end region is one of the critical objectives in the design of large generators. This paper describes a validated 3D finite-element analysis (FEA) that incorporates the nonlinear/anisotropic core property, core loss effects and the in-plane eddy current reaction to calculate the loss distributions in the end components. Then, by employing this 3D FEA method, a parametric study is carried out to evaluate the effectiveness of various candidate designs in reducing the losses in the end region, including the stepped profile of the end core packets, the assignment of the end tooth slits, the angle of the inclined armature end windings, and the relative axial lengths of the stator and rotor.