大型汽轮发电机轴电压和共模电压仿真建模研究

Modeling of Large Turbo-generator Shaft Voltage and Common Mode Voltage

针对励磁变二次侧星形连接的传统轴电压仿真模型不能揭示励磁变三相对地电容不平衡导致轴电压增大的局限性,首次建立了励磁变二次侧角形联结的大型发电机静止励磁的轴电压数值仿真模型,对静止励磁轴电压主要成分及其防治措施进行了仿真分析,并与1000MW发电机轴电压现场实测比对,得出静态励磁系统输出共模电压高频奇次谐波是大型汽轮发电机的主要轴电压源的结论。对励磁变二次侧角形联结的大型发电机的共模电压及轴电压进行了仿真,发现励磁变三相对地电容不平衡将导致共模电压畸变及轴电压增大,并仿真研究了相应的抑制策略。

This paper established large static excitation generator shaft voltage numerical simulation model with excitation transformer secondary side delta connection. Comparing with the field shaft voltage test results of a 1000MW generator, the main component of the static excitation shaft voltage and its control measures are analyzed. It is concluded that the high frequency harmonics of the common mode voltage of static excitation system output is the main source of shaft voltage. Simulation on the common mode voltage and shaft voltage under the condition of static excitation transformer secondary side angle connection and three-phase capacitance imbalance were carried out, and the common mode voltage distortion and shaft voltage increase in the case of the excitation transformer three capacitance imbalance were found and suppression measures were simulated.