大型水轮发电机转子偏心对单元件横差保护影响的分析

为了研究转子偏心对大型水轮发电机单元件横差保护的影响,采用多回路分析与有限元分析相结合的方法,建立了转子偏心下水轮发电机的数学模型,对发电机内部磁场进行有限元计算,得到了发电机在转子偏心下的电磁参数,然后通过多回路分析计算,获得了不同转子偏心率下单元件横差电流。计算结果表明,转子偏心故障达到一定程度时,单元件横差不平衡电流会超过保护动作定值,引起单元件横差保护的动作。

Analysis of the Effect of Eccentricity on Single Element Transverse Differential Protection in Large-sized Hydro-generator

To study the effect of eccentricity on single element transverse differential protection, multi-loop theory and finite element method are used to set up the mathematical model with eccentricity and obtain the expression of electromagnetic parameters. Based on the expression, the single element transverse differential current in several eccentricities is calculated. The result shows single element transverse differential protection would operate when the eccentricity reach some extent.