320 MW机组的振动分析与解决

天津大港发电厂2号机组2004年12月锅炉改造投产以来一直存在轴瓦振动超标的问题.利用在机组甩负荷试验期间,对2、3、4号瓦振动超标进行了现场动平衡处理.从最终的效果看,造成3、4号瓦振动异常的原因并不是转子的残余不平衡引起的,主要原因是由于低压转子轴承座系悬臂支撑方式,相对来说动刚度较低,同时末级叶片司太立合金严重冲蚀,导致蒸汽激振力增加,致使机组在30 MW负荷以下或空负荷时瓦振正常,在30 MW以上机组振动随负荷升高而增大.

Vibration Analysis of 320 MW Unit and Its Remedy

Excessive vibration of bearing liner for unit 2 in Dagang Power Plant exists since the boiler was renovated and put into service in Dec. 2004. During load rejection of the unit ,dynamic balance was made to reduce the excessive vibration for bearing liner 2,3,4 at site. The result shows bearing liner 3,4 excessive vibration was not caused by unbalance of rotor but by supporting method of LV rotor bearing seat. Its dynamic rigidity is lower,last blade stellite alloy was heavily eroded which caused the increasing vibration of steam, and as a result,the bearing liner vibration is normal when load is less than 30 MW or at zero,while vibration is greater when the load is above 30 MW and increasing with the rise of load.