超临界660MW机组可倾瓦故障引起异常振动分析

ABNORMAL VIBRATION CAUSED BY TILTING PAD FAULT IN 660 MW SUPERCRITICAL UNITS WITH AIR COOLING

某超临界660MW空冷机组4号轴承异常振动导致机组跳闸,其振动频谱以1/3倍频低频分量为主。分析认为,4号轴承的异常振动是由4号可倾瓦轴承上瓦弹簧折断引起。弹簧折断后,瓦块受力不均倾斜与折断弹簧对角的瓦块磨损,使瓦块受到的支撑力不稳定,从而引起轴承壳体不稳定振动。此类故障较为罕见,所引起的异常振动也较特殊。

Trip occurred in a 660 MW supercritical air cooling unit due to abnormal vibration on NO.4 bearing.The vibration spectrum mainly consists of low frequency component like third frequency doubling.Breaking of spring for upper tile of the NO.4 tilting pad bearing was considered as the basic reason.As soon as the spring broke,the adjacent tile suffered uneven stress,so it inclined and touched the tile at the diagonal position of the broken spring,causing abrasion and making the tiles suffer unstable supporting force.Therefore,unstable vibration of the bearing shell occurred.After repairing the metal on bearing shell and the shell pin hole,as well as changing the spring,the unit obtains a stable operation.