水轮发电机组空载状态下非线性运动特性分析

Analysis of Nonlinear Motion Characteristics of Hydrogenerator Unit under No-load Condition

鉴于不同类型的电磁力会对转子的稳定运行产生影响,从实际水轮发电机组运行特性出发,利用变阶数微分方程对发电机转子系统进行参数化建模,选定变步长求解器进行计算,结合轴心轨迹图及频谱图分析了不同电磁力对轴系摆度的影响,分别探讨了两种气隙对机组轴系摆度的影响程度。对比两工况的计算结果,发现均匀圆周电磁力有助于提高转子运行的稳定性;而在发电机几何不对中而引起的非均匀电磁力作用时,转子的运行状况有较为复杂的变化,不利于机组安全稳定运行,计算结果与现场检测数据互相印证。

Different electromagnetic forces will have different impacts on the stable operation of the rotor.Variable order differential equation was used to establish the parametric model of the generator rotor system based on the actual operation characteristics of hydraulic turbine generator unit.And the variable step size solver was selected for calculation.Then the influence of different electromagnetic forces on the shafting swing was analyzed by analyzing the orbit of shaft center and frequency spectrum.The influence degree of two kinds of air gap on the shafting swing was discussed.Compared with the calculation results of the two working conditions,it finds out that the uniform circumferential electromagnetic force helps to improve the stability of the rotor operation;When the non-uniform electromagnetic force caused by the geometric misalignment of the generator acts,the operation condition of the rotor has more complex changes,which is not conducive to the safe and stable operation of the unit.The calculation results and the field test data are mutually verified.