发电机转子倾斜偏心对绕组相电流的影响

Effect of rotor inclination eccentricity on winding phase current in generators

分析了发电机转子倾斜偏心故障前后的定子绕组相电流,推导出正常情况和转子倾斜偏心故障下的气隙磁通密度,得到定子绕组相电流的解析表达式。利用有限元仿真软件建立发电机故障前后的三维模型,对相电流进行了求解计算。在模拟发电机上进行了实测,三者所得结果基本吻合。结果表明:相电流在正常和转子倾斜偏心情况下仅具有50、150 Hz等奇次倍频成分;随着转子倾斜偏心程度增加,无论是单端转子倾斜偏心故障还是双端转子倾斜偏心故障,相电流的50、150 Hz倍频成分幅值都将增大;在倾斜偏心程度相同情况下,相对于双端转子倾斜偏心故障,单端转子倾斜偏心故障显著增加了相电流的50、150 Hz倍频成分幅值。

This paper analyses the phase currents of the stator winding before and after the rotor inclined eccentricity fault in generators.Firstly,the air gap flux density under normal conditions and rotor inclined eccentricity fault is first derived,and the analytical expression for the phase current is obtained.Then a three-dimensional model of the generator before and after the fault was established by finite element analysis(FEA)software,and the phase currents were solved and calculated.Finally,the actual measurements were carried out at the simulated generator and the three obtained results basically matched.It is shown that the phase currents have only odd octave components such as 50 Hz and 150 Hz in both normal and rotor inclined eccentricity cases.With the increase in the degree of rotor inclined eccentricity,the amplitude of the 50 Hz and 150 Hz components of the phase current will increase in both single-end rotor inclined eccentricity and double-end rotor inclined eccentricity faults.With the same degree of rotor inclined eccentricity,the amplitude of the 50 Hz and 150 Hz components of the phase currents increase significantly in single-ended rotor inclined eccentricity fault compared to double-end fault.