基于自适应时频分析的天然气管道泄漏检测

发布时间：2018-03-06 17:42

本文选题：管道泄漏检测　切入点：次声波　出处：《东北石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：为了保障管道的安全生产,管道泄漏检测技术是最为重要的手段。在进入21世纪以后,人们对管道泄漏检测提出了检测管道的微小泄漏、提高泄漏点的定位精度、提高系统对泄漏判断的准确率等要求。天然气管道泄漏产生的次声波信号属于非平稳信号,并且在管道中传播时受到严重的外界干扰,导致泄漏的误判率高,且定位不准确。自适应时频分析方法是分析非平稳信号的重要手段,针对天然气管道泄漏产生的次声波信号的特征,本文利用自适应最优核(AOK)时频分析算法,通过短时模糊函数和随时间变化的自适应最优核,实现管道内声信号的时频处理和时频特征的提取,提高管道泄漏判断和泄漏点定位精度,并结合Lab VIEW和MATLAB编程实现天然气管道泄漏检测系统。本文主要工作有:1、对现有常用的几种时频分析算法的基本理论进行研究,并对这几种时频分析算法的优缺点进行对比。对比结果表明AOK具有较高的时间、频率分辨率以及时频聚集特性,并且能够有效的抑制信号的交叉干扰项,用于天然气管道泄漏产生的次声波信号分析是一种理想的方法。2、根据天然气管道泄漏产生次声波的原理,对次声波在天然气管道中的传播、以及根据次声波对管道泄漏进行检测以及泄漏点的定位方法进行了研究。最后利用AOK时频分析算法对天然气管道泄漏产生的次声波信号进行时频处理,并将处理结果和其他几种时频分析算法进行对比,对比结果发现,AOK时频分析能够对管道泄漏产生的次声波信号进行准确的判断,并能准确的提取出泄漏发生的时间,对管道泄漏的判断和泄漏点定位精度的提高有较大的优势。3、根据现场的实际要求,利用图形化编程软件Lab VIEW对整个天然气管道泄漏检测系统的下位机采集系统、上位机监控系统和系统数据的传输进行了详细的设计。其中下位机采集系统主要包括管道声波信号的采集、声波数据的处理和特征提取、系统授时等模块的设计;系统数据的传输主要包含两种不同数据传输方式的发送和接收模块的设计;上位机监控系统主要包括了管道泄漏的判断、泄漏点的定位和报警、系统相关的数据显示、存储和查询、管道泄漏检测系统的权限管理等模块的设计。4、对编写的天然气管道泄漏检测系统在实验室环境和现场实际运行环境下进行测试。测试结果表明,该系统能够有效的对天然气管道发生的小泄漏进行检测并定位,定位精度符合现场的实际要求。
[Abstract]:In order to ensure the safety of pipeline production, pipeline leak detection technology is the most important means. After 21th century, people put forward to detect the small leakage of pipeline, improve the location accuracy of leak point. The infrasonic wave signal produced by natural gas pipeline leakage belongs to non-stationary signal and is seriously disturbed by the outside world when it propagates in the pipeline, which leads to high misjudgment rate of leakage. Adaptive time-frequency analysis method is an important method to analyze non-stationary signals. According to the characteristics of infrasonic signals produced by natural gas pipeline leakage, the adaptive optimal kernel AOK-based time-frequency analysis algorithm is used in this paper. By using the short time ambiguity function and the adaptive optimal kernel with time variation, the time-frequency processing and time-frequency feature extraction of acoustic signals in pipeline are realized, and the leak judgement and leak location accuracy are improved. The leakage detection system of natural gas pipeline is programmed by Lab VIEW and MATLAB. In this paper, the basic theory of several commonly used time-frequency analysis algorithms is studied. The advantages and disadvantages of these time-frequency analysis algorithms are compared. The results show that AOK has higher time and frequency resolution and can effectively suppress the cross-interference of the signal. The analysis of infrasonic wave signal produced by natural gas pipeline leakage is an ideal method. 2. According to the principle of infrasonic wave produced by natural gas pipeline leakage, the transmission of infrasonic wave in natural gas pipeline is studied. Based on the infrasonic wave detection of pipeline leakage and the location method of leak point, the time frequency analysis algorithm of AOK is used to process the infrasonic wave signal produced by natural gas pipeline leakage. By comparing the processing results with other time-frequency analysis algorithms, it is found that AOK time-frequency analysis can accurately judge the infrasonic signals produced by pipeline leakage, and can accurately extract the time of leakage. The judgement of pipeline leakage and the improvement of leak location accuracy have great advantages. According to the actual requirements of the field, the lower computer acquisition system of the whole natural gas pipeline leakage detection system is obtained by using the graphical programming software Lab VIEW. The monitoring system of upper computer and the transmission of system data are designed in detail, in which the acquisition system of lower computer mainly includes the collection of pipeline acoustic signal, the processing and feature extraction of acoustic data, the design of system timing module. The transmission of system data mainly includes the design of transmission and receiving modules of two different data transmission modes. The monitoring system of upper computer mainly includes the judgment of pipeline leakage, the location and alarm of leak point, the display of relevant data of the system. The design of storage and query module, authority management of pipeline leak detection system, etc., tests the developed natural gas pipeline leak detection system in laboratory environment and field operation environment. The test results show that, The system can effectively detect and locate the small leakage occurring in natural gas pipeline, and the positioning accuracy is in line with the actual requirements of the field.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE973.6

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