Transient Characteristic Analysis of Turbine Generator Based on Separated Partial Finite Element Model

This article presents an effective modeling method for electric machines to reduce the computational cost of finite element (FE) analysis coupled with circuit equations. In this method, center and end regions of the machines are separately modeled. The center of the machines is partially modeled considering their periodic structure. As a result, the total number of elements can be decreased. Moreover, the computational accuracy is kept unchanged by introducing two correction coefficients which adjust the total amount of magnetic flux across the coils. The proposed method is applied to the steady-state characteristic analysis of a turbine generator. It is shown that the proposed method can reduce the computational time to about one-third in comparison with the conventional FE model, while the computational results almost coincide with the measurements. Then, the proposed method is also applied to a time-consuming eddy current analysis of the turbine generator for estimating its transient characteristics. It is shown that the estimated transient constants of the turbine generator are in good agreement with the measured results.