汽轮机轴承故障引起的不稳定振动特征分析

Analysis of unsteady vibration symptom caused by turbine bearing fault

针对2台汽轮机轴承故障下的振动特征分析,指出不稳定振动是这类故障的典型特征。故障初期振动的波动较小,中后期逐渐增大,至不可控,不稳定振动与负荷关系不大。第2台机组故障实例分析表明,不稳定振动发生后频谱图中会出现较大的低频分量。2台机组在出现大幅度轴振波动的同时瓦振均较小,机组状态监测时应重点监测轴振变化,进而保护机组安全。

The symptom of vibration caused by bearing fault of two turbine units is analyzed in the paper. It is pointed that the unstable vibration is the typical symptom of this kind of bearing fault. The amplitude of the unsteady vibration is small in early state and become large in later period. There is no relationship between the vibration and load. The case analysis shows that sub-synchronous frequency occurs in the vibration frequency spectrum in case of bearing fault. Shaft vibration is small when bear vibration is big for the two units. It is important to monitor shaft vibration and its trend for the safety and reliability operator of the unit.