燃气轮机进口导叶角度偏差引发的突发性振动分析

Analysis on the Abrupt Vibration Caused by Angular Deviation of Inlet Guide Vane of Gas Turbine

某台燃气轮机发电机组运行中发生了突发性振动。启动升速过程中振动稳定,带负荷初期振动有一定幅度的随机性波动。随着所带负荷的增大,波动幅度越来越大。试验发现,振动波动时信号中出现了25 Hz的低频分量。突发性振动现象和滑动油膜失稳故障很相似。综合采取了提高轴承标高、减小轴承顶隙和增大轴承椭圆度等措施来提高轴承稳定性,未能取得预期的减振效果。考虑到振动和负荷之间存在较强关联性,得出燃气轮机进口导叶角度偏差引发的失速是突发性振动的主要原因;通过调整入口导叶开度,解决了机组振动故障,得出振动与负荷之间的关联性是区分油膜失稳和失速这两类相似故障的关键特征。

An abrupt vibration fault occurred on a gas turbine generator unit.The vibration was stable in the start-up process.There was a certain range of random fluctuation of vibration when the power was low.With the increase of the power,the fluctuation range became large.It was found that the low frequency component of 25 Hz appeared in the signal when the vibration was fluctuating.The abrupt vibration phenomenon was similar to that of oil whirl of journal bearing.The methods of improving bearing elevation,reducing bearing top clearance and increasing bearing ellipticity have been taken comprehensively to improve bearing stability.However,the expected vibration reduction effect has not been achieved.Considering the strong correlation between vibration and power,it is pointed out that stall of gas turbine is the main cause of unstable vibration.By adjusting the angle of the inlet guide vane,the vibration fault is solved.The correlation between vibration and power is the key feature to distinguish oil whirl fault and stall fault.