某超临界660MW机组异常振动分析与治理

某超临界660 MW机组运行中高中压转子热变形引起振动超标,通过现场高速动平衡进行了治理。振动治理过程中,#4瓦出现不稳定振动,#4瓦x、y方向轴振在升速至1100 r/min时开始迅速增大,至1390 r/min时轴振已达到跳机值。振动大时,振动频谱中主要为1/3倍频成分。分析认为#4轴瓦不稳定振动是由可倾瓦故障引起的,揭瓦检查发现可倾瓦瓦块与壳体之间的支撑弹簧折断,瓦壳体柱销孔磨损4 mm。更换弹簧并修复瓦块后机组顺利升速到3000 r/min。

Analysis and Treatment of Abnormal Vibration Occurred in a 660MW Supercritical Turbo-generator Unit

By high speed dynamic balance,abnormal vibration caused by the thermal deformation of high pressure rotor during operation process of a supercritical 660MW unit is dealed with.After the second dynamic balance,vibration amplitude of #4 bearing climbs rapidly when the unit starts up to 1100rpm.As the speed reaches to 1390rpm,the vibration amplitude reaches as high as 250μm,which is the threshold to let the unit shutdown.The vibration spectrum is 1/3 frequency component primarily.It is believe that unstable vibration is caused by the failure of #4 tilting-pad journal bearing.Checked up the bearing carefully and found that the spring which installed between the tilting-pad and shell has broken and the pin hole on the bearing shell is wear down at a quantity of 4mm.Repair the bearing and the unit rise to 3000rpm smoothly.