某300MW机组高中压转子振动故障的准确诊断

Accurate Diagnosis of Abnormal Vibration of High-Medium Pressure Rotor in a 300-MW Unit

针对某300 MW机组运行中高中压转子振动爬升问题,通过分析冷态和热(温)态转子振动特性差异和转子弯曲量的减小等异常情况,诊断振动故障源于转子存在裂纹,热态下导致转轴刚度的降低和平衡状态的恶化。抽转子探伤检查发现转轴确实出现严重的裂纹,证实了诊断结论的准确性。及时停机检查和发现裂纹避免了机组继续运行可能发生的断轴毁机灾难性事故。文章还分析了该转子裂纹的产生过程以及对火电机组深度调峰和灵活性运行可能对转子安全性产生的影响。

Aiming at the problem of vibration climbing of the high-medium pressure rotor during the operation of a 300-MW unit, this paper analyzes the abnormal situations such as the differences in vibration characteristics of the rotor between cold and hot （warm） states and the decrease in rotor bending and concludes that the vibration problems are caused by the cracks in the rotor, which lead to the decrease of the rotor stiffness in the hot state and the damage of the rotor balance. The rotor detection shows that there are severe cracks in the rotor shaft. The detection confirms the accuracy of the diagnosis. The timely shutdown and maintenance as well as the detection of the existence of the cracks, have prevented the unit from potential shaft break and collapse. Moreover, the producing process of the rotor cracks and the possible impacts of in-depth peaking load and flexible operation of thermal power units on the rotor safety are also studied in this paper.