水电站机组及厂房振动信号精细分频分析

发布时间：2018-01-08 08:41

本文关键词：水电站机组及厂房振动信号精细分频分析　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：水电站机组振动及其诱发的厂房结构振动是涉及水电站的安全稳定运行的重大问题。已投产的大型水电站都出现了不同程度的振动问题,对电站的正常运行和工作人员的安全造成了威胁;随着现代水轮机组向高水头方向发展,其动力学特性会出现一些新的特点,对机组安全稳定运行造成影响的未知因素也会相应增多。因此,对水电站机组和厂房结构的振动规律进行研究,可以为以后水电站的设计和运行提供参考,是水电建设工作中十分有价值的研究课题。本文结合一高水头、长隧洞的引水发电电站,通过对其进行现场真机试验采集振动信号,并对信号进行精细分频分析,达到研究其振动规律的目的。主要研究内容及结论包括:(1)通过对该电站振源的分析,发现其机组及厂房的振动信号具有频域范围广、振源频率较明确、各振源能量悬殊等特点;针对以上特点,结合小波变换和小波包变换理论,建立了一种精细分频的分析方法。(2)采用精细分频方法,对该电站变负荷真机试验的机组和厂房结构各个关键测点的振动信号进行了分析,将其分解成多个在频率域上相对单一的振动信号,以解释该水电站机组及厂房的振动原因。分析结果表明,0~1Hz频带在多数测点的振动信号中占据了主要能量,尤其表现在测点顺河向和垂向的低负荷工况的振动信号中;低频的水力振源是引起该类电站振动的主要原因。(3)在前人研究的基础上,对该电站压力管道水体的振动特性进行了研究,分析了其产生水体共振的可能性。分析结果表明,该电站压力管道水体自振频率为0.45~0.9Hz,与尾水涡带0.463~0.927Hz的频率范围存在部分重合区域;因此,该电站存在水体共振的可能性。(4)通过对密集模态判别方法的总结,以及对仿真信号模态识别的试验,选出了对信号加逆衰减指数窗,再进行精细分频这一适合密集模态分离的方法,对所研究的水电站厂房的振动数据进行了模态识别。
[Abstract]:The vibration of hydropower unit and its induced vibration of powerhouse structure is an important problem which involves the safe and stable operation of hydropower station. The large hydropower stations that have been put into production have different degrees of vibration problems. Posed a threat to the normal operation of the power station and the safety of the staff; With the development of modern hydraulic turbine unit towards high water head, some new characteristics will appear in its dynamic characteristics, and the unknown factors which will affect the safe and stable operation of the unit will increase accordingly. The research on vibration law of hydropower unit and powerhouse structure can provide reference for the design and operation of hydropower station in the future and is a very valuable research topic in hydropower construction. In the power station of long tunnel, vibration signals are collected by real machine test in the field, and the signal is analyzed by fine frequency division. The main research contents and conclusions include: 1) through the analysis of the vibration source of the power station, it is found that the vibration signal of the unit and workshop has a wide range of frequency domain and the frequency of vibration source is clear. The characteristics of energy disparity of each vibration source; According to the above characteristics, combining the theory of wavelet transform and wavelet packet transform, an analysis method of fine frequency division is established. The vibration signals of each key measuring point of the unit and powerhouse structure of the power station with variable load are analyzed and decomposed into several relatively single vibration signals in the frequency domain. In order to explain the vibration reason of the unit and powerhouse of the hydropower station, the analysis results show that the 1Hz frequency band occupies the main energy in the vibration signals of most measuring points. Especially in the vibration signal of the low load condition along the river and the vertical direction of the measuring point; Low frequency hydraulic vibration source is the main cause of the vibration of this kind of power station. Based on the previous research, the vibration characteristics of the water body of the pressure pipeline of the power station are studied. The possibility of water resonance is analyzed. The results show that the natural vibration frequency of the water body of the power station is 0.45 ~ 0.9Hz. There is a partial overlap region with the frequency range of 0.463 ~ 0. 927 Hz in the tailwater vortex zone. Therefore, the possibility of water resonance in the power station. (4) through the summary of the method of dense modal identification and the experiment of simulation signal modal identification, the signal with inverse attenuation exponent window is selected. Then fine frequency division, which is suitable for intensive modal separation, is used to identify the vibration data of hydropower plant.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV734

【相似文献】