电机定子结构及其绝缘介电常数的频率特性对定子绕组电容值的影响

确定电机定子线棒的高频参数对于研究局部放电信号在电机绕组中的传播特性及研究PWM逆变器驱动的交流电机的定子绕组电压分布有重要意义。文中对大型汽轮发电机定子线棒的电容做了比较详细的研究，内容包括：对电机定子线棒复合绝缘等值介电常数的频率特性的测试研究、采用数值计算方法计算出用铝箔纸裹住的电机定子线棒的多导体传输线模型的单位长度电容、线棒股线间薄绝缘对电容的影响、对铁心硅钢片叠片间隙对电容的影响等。其数值计算结果与之前测量得到的电容值比较吻合，这也证明了通过测量开路阻抗、短路阻抗来得到电机定子线棒分布参数的试验方法是有效的。

THE EFFECT OF STRUCTURE AND FREQUENCY CHARACTERISTIC OF DIELECTRIC CONSTANT ON CAPACITANCE OF ELECTRICAL MACHINE STATOR WINDING

Determining the electrical machine stator windings parameters at high frequency is significant for analyzing the propagation of partial discharge signals in windings of electrical machines and voltage distribution on stator windings of AC electrical machine driven by PWM inverters. This paper describes the research on capacitance of large turbine generator, including the measuring result of frequency characteristic of dielectric constant of stator windings insulation material, calculating result of capacitance of per unit length of stator windings wrapped in aluminum paper by numerical computation, the effect of insulation thin layer among strands of stator bar on its capacitance, the effect of iron core laminations space on its capacitance etc. The result of numerical computation coincides with the measured, and also shows that the experimental method of getting stator windings parameters by measuring open circuit impedance and short circuit impedance is effective and reasonable.