空冷汽轮发电机端部电磁场与涡流损耗研究

Research of end fields and eddy current losses for air-cooling steam-turbo-generator

针对大型空冷汽轮发电机端部磁场分布和各结构件的涡流损耗难以准确计算的问题,对大型空冷发电机端部结构进行三维实体建模,建立了电机端部三维非线性瞬态涡流场的数学模型,阐述了对激励源的选择和结构件建模的方法,较全面地考虑了材料特性、结构件形状等因素对电机性能的影响。以一台200MW空冷汽轮发电机为例,用有限元法对其在额定工况下的端部电磁场分布和结构件中的涡流损耗进行计算。将所得的结果与实测值进行比较,分析表明误差在工程应用的允许范围内,表明此种方法可以用于大型空冷汽轮发电机的端部电磁场与涡流损耗的计算当中。

It is difficult to accurately calculate the distributions of end-electromagnetic fields and the eddy current losses of end structures in air-cooling steam turbo-generators, so the mathematical model of 3 D end-transient magnetic fields based on 3D full-model of the end of the steam turbo-generator was shown in this paper. The options of excitation source and the means of constructing model were introduced, and the effects of the material characteristics and shapes of structures were fully considered in this model. Finally, taking a 200MW air-cooling steam turbo-generator as example, the accurate calculation of distributions of end-electromagnetic fields and the eddy current losses of structures in end region of air-cooling steam turbo-generators with the finite element method were given in the paper. The results was compared with the measured values, and the error of the enginerring application was in the allowable range. It proves that the method can be used in the calculation of the end of the electromagnetic field and eddy current loss for large air-cooled turbo generator.