水轮机压力脉动信号采集方法的研究

Research on Pressure Fluctuation Signals Sampling for Hydraulic Turbine

通过对大量试验资料的分析 ,针对目前广泛使用的FFT分析法 ,介绍了在水轮机压力脉动试验过程中可能产生的信号混叠和信号频率泄漏现象 ,提出了在采用FFT分析时较为合理的信号采集方法。由于在进行FFT分析时 ,先对连续的压力脉动信号进行了有限化和离散化处理 ,从而使分析得到的频率、幅值和相位产生误差。要提高FFT分析的频率分辨率 ,必须加长数据采样时间 ;要提高高频分析的精度 ,则应提高采样频率 ,缩短采样间隔。

The Pressure fluctuation signals sampling is researched through the analysis about a lot of test data.In accordance with the method of FFT frequency analysis,the phenomenon of signals aliasing and leakiness at the turbine pressure fluctuation test is introduced.The reasonable sampling method is suggested when using FFT frequency analysis,in order to avoid some errors of analyzed results with limitation and discrefization of continuous pressure fluctuation signals.