大型水电站地下厂房振动特性反馈研究

发布时间：2019-06-19 09:09

【摘要】：近年来，在全球经济增长、气候变化与水资源日益紧张的形式下，水力发电作为一种可再生的清洁能源备受中国政府的重视。在过去的半个多世纪里，我国的水利水电事业得到了快速的发展，并取得了丰硕的业绩。但随着一大批大规模、高水头、大容量西部水电开发项目的建成与运行，水轮发电机组振动与水力脉动诱发的厂房混凝土结构的振动问题越来越突出，甚至危及水电站及周围建筑物的安全。本文结合某大型水电站地下发电厂房实际工程情况，对其进行现场实测数据分析与数值模拟分析，主要包括的研究内容有：（1）基于一大型水电站机组与厂房结构的变负荷、开停机、甩负荷和发电机升压工况运行试验的振动实测数据，研究了机组与厂房结构的幅值特性和频率特性以及不同工况下振动位移或脉动压力的变化规律并对振动状况作出评价。（2）由于水电站厂房结构是一种复杂耦联的非线性系统，其振动问题属于复杂的动力学问题。本文采用相关性分析理论对地下厂房结构进行振源识别、水-机电-结构耦联振动特性以及机组振动与水力脉动的传递规律的分析。在此基础上，利用相关向量机回归算法进行厂房结构的振动预测。（3）水电站厂房结构振动的激振力难以测得，给结构模态参数识别带来了困难。为此本文提出一种基于环境激励的厂房结构模态参数识别法，即将EEMD，RDT和STD相结合的方法，由于EEMD有效缓解了模态混淆问题，较EMD方法更有助于结构低阶振动模态参数的识别。（4）利用有限元分析软件(ANSYS)建立电站地下厂房结构三维模型，，对其进行了自振特性分析与共振校核。基于厂房结构实测振动位移数据，采用谐响应动力分析，对厂房机墩的垂直动荷载进行了反馈研究，并计算了厂房结构在动荷载作用下的响应；同时计算了厂房结构在水力激励下的共振频率、振动响应及应力。
[Abstract]:In recent years, under the form of global economic growth, climate change and water resources, hydropower, as a renewable clean energy, has been paid more and more attention by the Chinese government. In the past half century, the cause of water conservancy and hydropower in China has been developed rapidly and achieved fruitful achievements. However, with the completion and operation of a large number of large-scale, high-head and large-capacity western hydropower development projects, the vibration of hydro-generator set and the vibration of concrete structure induced by hydraulic pulsation are becoming more and more prominent, and even endanger the safety of hydropower stations and surrounding buildings. In this paper, the field measured data analysis and numerical simulation analysis are carried out according to the actual engineering situation of the underground power plant of a large hydropower station. The main research contents are as follows: (1) based on the measured vibration data of the operation test of the unit and powerhouse structure of a large hydropower station, start and stop, load rejection and generator boost condition, The amplitude and frequency characteristics of the unit and the factory building structure and the variation of vibration displacement or fluctuating pressure under different working conditions are studied and the vibration condition is evaluated. (2) because the powerhouse structure of hydropower station is a kind of complex coupled nonlinear system, its vibration problem belongs to complex dynamic problem. In this paper, the correlation analysis theory is used to identify the vibration source of underground powerhouse structure, the coupled vibration characteristics of water-electromechanical structure and the transfer law between vibration and hydraulic pulsation of the unit are analyzed. On this basis, the correlation vector machine regression algorithm is used to predict the vibration of the factory building structure. (3) it is difficult to measure the excitation force of the structural vibration of hydropower station powerhouse, which brings difficulties to the identification of structural modal parameters. In this paper, a modal parameter identification method of factory building structure based on environmental excitation is proposed, that is, the combination of EEMD,RDT and STD. Because EEMD effectively alleviates the problem of modal confusion, it is more helpful to identify the modal parameters of low-order vibration than EMD method. (4) the three-dimensional model of underground powerhouse structure of power station is established by using finite element analysis software (ANSYS), and its natural vibration characteristics are analyzed and resonance checked. Based on the measured vibration displacement data of powerhouse structure, the vertical dynamic load of powerhouse pier is studied by harmonic response dynamic analysis, and the response of powerhouse structure under dynamic load is calculated, and the resonance frequency, vibration response and stress of powerhouse structure under hydraulic excitation are calculated at the same time.
【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】：TV731.6;TV312

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