交叉小波变换在水轮机非平稳信号分析中的应用  

Application of Cross-wavelet Transform to Hydraulic Turbine Nonstationary Signal Analysis

作　　者：张进[1] 冯志鹏[2] 卢文秀[1] 褚福磊[1] 

机构地区：[1]清华大学精密仪器与机械学系,北京市海淀区100084 [2]北京科技大学车辆工程研究所,北京市海淀区100083

出　　处：《中国电机工程学报》2010年第23期84-89,共6页Proceedings of the CSEE

基　　金：国家自然科学基金项目(10702031;50705007);北京市自然科学基金项目(3102022)~~

摘　　要：水压脉动是影响水力发电机组振动的主要因素之一。分析水压脉动与机组振动之间的相关性对于研究水压脉动对机组振动的影响机制具有重要意义。该文应用交叉小波变换在时频空间中分析水轮机导轴承振动和尾水管出口、蜗壳进口、顶盖下等3个典型水压脉动之间的相关性,提取机组振动与水压脉动之间的相关性随时间和频率变化的特征。分析结果表明:水压脉动以低频为主,不同测点的水压脉动会引起机组在不同时刻产生不同频率的低频振动,其时变特征与机组运行条件密切相关。与传统的互相关分析对比,交叉小波变换更能全面精细地刻画出2个信号之间相互联系的结构特征。Hydaulic pressure fluctuation is one of major factors influencing the vibration of hydraulic turbines. Correlation analysis of the hydaulic pressure fluctuation and the vibration is important to reveal the hydaulic pressure fluctuation induced vibration. Cross-wavelet transform was used to analyze the vibration at water turbine guide bearing and the hydaulic pressure fluctuation at draft tube, spiral case and headcover in time-frequency joint domain. The time-frequency correlation between the vibration and the hydaulic pressure fluctuation was extracted. It is found that the hydraulic pressure fluctuation has low frequency feature and can induce the hydroturbine vibration at different time and frequency. The vibration amplitude and frequency are time varying and closely related with the operation conditions. Compared with the traditional cross-correlation analysis method, the cross-wavelet transform has the advantage in well characterizing the correlation between signals in time-frequency domain.

关 键 词：水轮机 水压脉动 时频分析 交叉小波变换 

分 类 号：TH17[机械工程—机械制造及自动化]