1000 MW超超临界机组发电机调试期间振动问题的分析及处理

Vibration analysis and treatment of a 1 000 MW ultra-supercritical unit during the commissioning

某1000 MW超超临界汽轮发电机组在调试期间,出现发电机低转速下转轴振动大、带负荷时发生轴振突跳及热弯曲等振动故障。结合发电机结构、升速过程伯德图、轴振突跳时的时域波形、转子发生热弯曲前后的工频幅值/相位变化情况进行分析,判断振动故障原因为发电机转子存在副临界转速,#6,#7轴承轴振存在虚假值且带负荷过程中发电机转子发生热弯曲。现场通过提高机组转速、调整转子与碳刷的接触面积及热平衡方法,消除了发电组振动故障。该方法对同类型机组类似的振动故障诊断和处理具有一定借鉴意义。

There were abnormal vibrations of a 1000 MW ultra supercritical turbo-generator set during its commissioning,such as large vibration at low speed,sudden axle vibration jump and thermal bending under loading.Based on the analysis of generator structure,Bode diagram during acceleration process,time-domain waveform of sudden vibration jump of rotor shaft,and phase/amplitude variations at power frequency before and after rotor thermal bending,it is judged that the causes of abnormal vibration are the sub-critical rotating speed of generator rotor,false value of No.6 and No.7 bearing vibration,and thermal bending of generator rotor during loading.Abnormal vibration of the generating unit can be eliminated by increasing the rotating speed of the generating unit,adjusting the contact area between rotor and carbon brush and taking heat balance method.These methods have certain referential significance for fault diagnosis and treatment on units of the same type.