大型水轮发电机转子偏心下电感参数的有限元计算

FEM analysis of the inductance parameters in a large hydro-generator with eccentricity

由于实际生产中,大型水轮发电机的转子往往存在不同程度的偏心现象,造成气隙磁场分布畸变,直接影响发电机运行,故为探讨发电机偏心下的运行性能,需要计算转子偏心时的电机参数。采用二维磁场有限元法,计算了大型水轮发电机在转子偏心下的磁场分布以及定子和转子绕组的自感、互感参数。有限元分析和磁导法计算结果比较表明:转子偏心造成定子支路间、定转子支路间的电感不再对称,偏心朝向处的定子支路自感和定转子支路互感变大,反向处则变小。

Some eccentricity always exists in hydro-generators which results in changes of the air gap magnetic field and influences the generator operation. The effect of the eccentricity can be analyzed by modeling the generator. A 2D finite element method （FEM） was used to model the magnetic field distribution with the eccentricity, self-inductance parameters and mutual-inductance parameters included. Comparison of the inductances calculated using the FEM and the magnetic conductance method showed that the inductance in the stator winding branch or between the stator and the rotor winding branch in the hydro-generator are no longer symmetrical because of the eccentricity. Both the inductance in the stator winding branch where the air gap is smallest and the mutual inductance between this stator winding branch and the rotor winding branch will increase, while the inductances in the opposite direction will decrease.