大型汽轮发电机组扭振试验中激振方法的研究

目前大型汽轮发电机组轴系扭振特性的现场试验中广泛采用稳态不对称短路变频激振法，该方法能有效地测得轴系的低阶固有频率，而难于或测不到高阶固有频率。为寻求其中的原因和规律性，本文用模态分析方法，以２００ＭＷ汽轮发电机组为对象，对轴系扭振试验过程中的动态响应进行了数值仿真，计算结果与现场测试结果完全一致，研究同时表明，在一定试验参数下，高阶振型也是能够被激起的，这些结论对现场试验有指导意义。

The Investigation of Excitation Methods in Torsional Test of Large-scale Steam Turbine Generator

Presently,the method of steady state unbalanced currents is widely used in the field test of torsional vibration characteristics of large-scale steam turbine generator rotor system. The natural frequencies of lower modes can be derived effectively by this means, but the higher modes can not be determined easily. To find the cause of this phenomenon, modal analysis technique is employed in this paper to simulate digitally the dynamic response in the torsional vibration test of 200MW steam turbine generator rotor system. The calculations are consistent with the field experimental results that the higher modes are difficult to be excited by this method. The research also indicates that the higher modes can be excited in certain experimental parameters. This conclusion provides an effective tool in future field tests.