水轮机非平稳振动信号的小波分析

Wavelet analysis on non-stationary vibration signal of hydraulic turbines

基于水电站机组振动的现场试验研究,利用小波分析方法在时域和频域上同时具有良好局部化性质的特点,对开停机这一典型非平稳过程信号进行小波分析。通过将信号分解到不同频带内,并对分解信号作振源分析和统计分析,以获取优势频率等有用信息。试验结果表明,水流脉动压力和尾水涡带摆动是引起开机过程中机组强烈振动的主要原因,同时也证明了小波是处理非平稳信号的最有力的工具。

According to the research on the field test for the vibration of hydraulic generating units, a typical non - stationary signal of on - off operation is analyzed by wavelet method with its characteristics of good location properties in both time and fre- quency. The signal is decomposed into different frequency bands, and then source analysis of vibration and statistical analysis on the decomposed signals are conducted to obtain the useful information such as dominant frequency. The result indicates that strong vibration in starting process is mainly caused by flow fluctuating pressure and swing of tailrace eddy.