给水泵汽轮机振动分析与处理

Analysis and Treatment of Feed Pump Turbine Vibration

某电厂与600 MW汽轮发电机组配套的给水泵汽轮机2号轴承在运行中轴振动随负荷升高而逐渐增大至89μm,超过报警值80μm,其间进行2次现场动平衡试验均未能解决其振动问题。为此,分析了产生振动的原因,通过振动测试发现轴承振动主要以基频为主,结合给水泵汽轮机运行参数及机组低转速下的状态进行分析,认为振动故障的根本原因是轴颈偏移值过大,次要原因是系统泄漏导致转速上升使不平衡激振力增大。根据检查结果,对事故进行了处理:调整好盘车齿套与给水泵汽轮机侧半挠性联轴器同心度后,重新铰孔,配制新螺栓,更换再循环阀的阀心与阀座,打磨涡流传感器测点位置,最终使汽轮机振动问题得以解决。

The axle vibration of Bearing 2 rosc to 89 μm（surpassing the warning value of 8（1 μm）with the load increase during thc operation of feed pump turbine for 600 MW turbo-unit in some power plant, during which time locale dynamic balancing was conducted twice but still failed to solve the problem. Therefore, the reasons for the vibration were analyzed. It was found by vibration test that the vibration consisted chiefly of fundamental frequency.An analysis was made combined with the opcration parameter of feed pump turbine as well as the state of unit at low rotary speed. It was concluded that the primary reason of the problem was the excessive journal drift： the second reason was the excessive raise of unbalanced exciting force caused by the escalated rotary speed due to system leakage. Treating measures were taken accordingly, i.e. adjusting the concentricity of the gear bush of barring and the semi-flexible coupling on the side of feed pump turbine, rereaming the hole, prcparing new bolts, replacing the valve core and valve seat of recycle valve and polishing the measuring point of vortex flow transducer, thus solving the vibration problem of turbine.