汽轮发电机磁路饱和与磁场畸变共同作用对运行的影响

Influences of Interaction Between Magnetic Saturation and Magnetic Field Distortion on Turbine Generator Operation

以300 MW汽轮发电机为实例,以有限元方法为工具,研究大型汽轮发电机在临界失稳条件下磁路饱和与磁场畸变共同作用的本质特点及其对运行的影响。通过对比分析不同饱和程度和不同功角下的磁场分布、磁密波形及感应电势等,发现两者共同作用不仅会导致产生相同气隙电势所需的合成磁势发生变化,而且还会引起磁密波形对称性及其谐波含量的显著变化;进一步研究了这些变化对给定负载下的励磁电流、气隙磁场方向、电势波形和定子铁心齿部磁密波形的影响。上述结果为进一步研究发电机在非正常运行条件下的模型和参数提供重要参考。

Taking 300MW turbine generator as an example, the paper studied the natural characteristics of the interaction of magnetic saturation and magnetic field distortion and its influence on operation under critical instability condition by means of finite element method.By comparing and analyzing magnetic field distribution,magnetic flux density waveform, inductive electric potential and so on under different saturation degrees and power angles,it is found that their interaction not only causes changes in resultant magnetomotive forces producing the same air-gap potential,but also leads to the prominent changes in symmetry of magnetic flux density waveform and its harmonics content.Further research is done about the influences of these changes on the field current,the direct of air-gap magnetic density,potential waveform and magnetic flux density of stator teeth under the given load conditions.The above results can be helpful to further study on models and parameters of generators under abnormal conditions.