某机组轴系振动突变的原因分析及处理

Analysis and Treatment of Sudden Fluctuation of Rotor Vibration in a Turbine Unit

某330 MW汽轮机因振动突然增大而跳闸。从振动机理出发,对可能的原因逐项进行分析,最终确认停机的根本原因是动静碰磨。在自动发电控制(AGC)和一次调频投入的情况下,GV1的阀门控制卡端子板电容老化烧损,导致GV3随负荷频繁大幅波动,引起1号和2号轴承油膜刚度变化,使轴承振动发生大幅波动,激发了高压转子二阶振动,最终使得轴封处发生动静碰磨。研究成果可为汽轮发电机组轴系振动突变原因的分析提供参考,为今后类似故障的处理提供借鉴。

An unplanned trip caused by sudden increase of rotor vibration occurred in a 330 MW steam turbine.According to the mechanism of vibration,the possible causes were analyzed,and it was confirmed that the root cause of shutdown was rubbing between rotating and stationary components.When the automatic generation control(AGC)and primary frequency modulation were put in,the capacitance of the valve control card terminal board of GV1 was burnt due to ageing,which caused great fluctuation of GV3 with the load,thus the oil film stiffness of No.1 and No.2 bearing was changed,leading to great vibration fluctuation of bearing.Therefore,the second order vibration of high pressure rotor was excited,resulting in the rubbing between rotating and stationary components at the shaft seal finally.The research results can provide reference for the cause analysis on the sudden fluctuation of rotor vibration in turbine generator unit and treatment of similar faults in the future.