抽水蓄能机组发电电动机停机过程振动分析

Vibration Analysis of Pumped Storage Generator-Motor in Shut-down Process

针对某蓄能机组,对不同工况下停机过程的发电电动机固定部件振动进行了测试,采用时域与频域分析方法对上机架、定子基座和下机架振动信号进行了分析。借助于时域信号混频幅值分析获得了停机过程中固定部件的振动混频幅值趋势;采用窗口傅里叶变换识别了停机过程中固定部件的频率成分,主要频率成分包括动静干涉频率、一倍叶片过流频率、一倍和二倍推力瓦通过频率等。分析表明,在机组停机过程中激发了固定部件共振频率。经与关键结构部件共振特性计算进行对比分析,指出了设计阶段存在考虑工况不足的缺点,导致在启、停机过程中厂房与机组存在共振的风险。

The static component vibrations of generator-motor in a pumped-storage station in shut-down processes from different working points arc measured, and the methods in time-domain and frequency-domain analysis are used to analyze the vibration signals of upper bracket, lower bracket and stator foundation. The vibration peak-to-peak value trends are obtained by analyzing time-domain signal peak-to- peak values. The frequency characteristics are also gotten by using short-time Fourier transform method. The frequencies of static components mainly include rotor-stator interference frequency, turbine blade passing frequency and thrust bearing pad passing frequencies. The time-frequency analysis also indicates that the natural frequencies of static components are excited during shut-down process. After comparing with the dynamics calculation reports of key components, insufficient considerations during designing stage are pointed out, which can lead to the resonance risk between powerhouse and units in starting and shut-down processes.