发电机转子弯曲振动问题分析与处理

Diagnosis on Vibration Problem of Generator with Bending Rotor

某水电厂水轮发电机组由于运行故障,造成发电机转子塑性弯曲,机组检修后启动振动超标。通过对机组启动、加励磁、升负荷过程振动频谱的监测分析,判断引起振动异常的原因包括原始的弯曲和加励磁后的临时热弯曲。二者相互关联,共同引起机组在升速和带负荷过程中振动幅值的大幅爬升。根据诊断结果确定处理方案,先将发电机转子铣直后重新进行现场平衡,最终将转子的振动控制在合格范围内,彻底解决了振动异常问题。通过对弯曲发电机转子的振动特性分析和处理,分析了转子弯曲情况下的平衡响应变化及热弯曲情况变化等。

Over-vibration occurred during startup of a hydro-generator unit because of permanent bending of rotor caused by operating failure.The fault diagnosis was carried out by studying the vibration spectrum under different operating conditions including speed up,excitation,load up and full load.Result shows that permanent bending and thermal bending after excitation are the main reasons leaded to the high vibration amplitude of the generator.Relevant approach of on-site balancing after straightening rotor is conducted to keep the shaft vibration at the safety level.By analyzing the vibration characteristics of a bending rotor,the balance response and thermal bending changes are summarized.