国产600MW汽轮发电机组轴系动平衡研究

Dynamic Balancing of the Shaft System for a Domestic 600 MW Turbo-Generator Set

针对国产600MW汽轮发电机组运行中普遍存在的轴系异常振动问题,分析了振动现象、振动特征、振动机理及其原因,并对现场动平衡问题的处理方法进行了总结.结果表明:国产600MW高中压转子由于结构不对称存在较大的振型干扰,现场对转子进行动平衡时应考虑各阶振型的干扰系数,尤其是一阶配重对二阶振型的影响;部分机组低压转子轴承座振动超标的原因为采用坐缸式轴承座的支承刚度不足,现场可以通过精细动平衡来消除;发电机转子振动主要呈现三阶振型,现场校正三阶不平衡的方法就是在低-发对轮或发-励对轮上加重,且在动平衡分析时应注意区分振型畸变;集电小轴的振动受发-励对轮的安装工况影响较大,现场对其进行动平衡分析时应考虑发-励对轮下张口对加重响应的影响.

Aiming at the vibration problems frequently occurring in operation of domestic 600 MW turbo-generator sets,an analysis has been carried out on the vibration phenomenon,feature,mechanism and the causes,while various countermeasures for on-site dynamic balancing summarized.Results show that large vibration disturbance exists in domestic 600 MW high-and medium-pressure rotors due to their asymmetric structures,to overcome which,the disturbance coefficient of various vibration modes and orders should be considered during on-site dynamic balancing process of rotors,especially the influence of one-order weighing on two-order vibration mode.The abnormal vibration occurring in low-pressure cylinder of some domestic sets are caused by insufficient rigidity of supports for relevant bearing seats,which may be handled by fine dynamic balancing on site.The vibration of generator rotor is mainly of the three-order mode,which may be corrected by adding balancing weight on the shaft coupling between low-pressure rotor and generator rotor,or on the shaft coupling between generator rotor and exciter rotor,in consideration of the distortion of vibration mode.The vibration of electricity gathering shaft is highly affected by the installation quality of the shaft coupling between generator rotor and exciter rotor,for which attention should be paid to the influence of weighing response at bottom opening of the shaft coupling between generator rotor and exciter rotor,during corresponding dynamic balancing analysis on site.