输油管道次声波法泄漏检测与定位技术研究

发布时间：2019-02-16 05:24

【摘要】：随着近年来仪器仪表技术、现代信号处理技术以及计算机技术的不断发展,基于信号的管道泄漏检测系统也逐渐普及。由于次声波频率低,波长长、衰减慢、在气体和液体中均可以传播等特点,基于次声波信号的管道泄漏检测方法已经成为最精确的方法之一。通过研究管道泄漏声波信号的传播原理,建立了管道泄漏报警模型和漏点定位模型。采用去均值法对获取的管道正常运行工况和泄漏工况的声波信号进行预处理,进而分析两种工况下,管道内声波时域、频域、时频域的信号特征。通过仿真实验对比分析发现,互相关法在抗噪声干扰能力和时延估计的精确性都要高于自适应最小均方误差时延估计方法;通过分析现场实验数据,与小波分析,小波去噪进行对比,小波包分析可以更加精准的提取次声频段信号。在国内某长输管道上现场进行实验,对比两种时延估计方法分别与小波变换理论相结合的方法。实验结果最终表明采用小波包分析的特征提取加上互相关分析的时延估计方法,可以很好的提高漏点定位精度。通过分析定位精度影响因素,流体流速的误差对最终漏点定位精度有着很大影响。最后基于美国国家仪器(NI)公司研制开发的Lab VIEW程序开发环境,开发了“管道泄漏检测系统”主要部分。该系统具有实用性广、操作方便、定位精度高等特点,同时该系统也能适用于其它油气管道泄漏检测与定位。
[Abstract]:With the development of instrument technology, modern signal processing technology and computer technology, pipeline leak detection system based on signal is becoming more and more popular in recent years. Because infrasonic wave has the characteristics of low frequency, long wavelength, slow attenuation, and can be propagated in both gas and liquid, the pipeline leakage detection method based on infrasound signal has become one of the most accurate methods. By studying the principle of acoustic signal propagation in pipeline leakage, the leakage alarm model and leak location model are established. The signal characteristics of acoustic wave in time domain, frequency domain and time frequency domain are analyzed by means of de-mean method to pre-process the acoustic signals obtained under normal operation condition and leakage condition. The simulation results show that the accuracy of the cross-correlation method is higher than that of the adaptive minimum mean square error (MMSE) method in the estimation of noise interference and time delay. Compared with wavelet analysis and wavelet denoising, wavelet packet analysis can extract infrasound frequency signal more accurately. In this paper, two methods of time delay estimation are compared with wavelet transform theory. The experimental results show that the time delay estimation method based on wavelet packet analysis and cross-correlation analysis can improve the accuracy of leak location. By analyzing the influence factors of positioning accuracy, the error of fluid velocity has a great influence on the location accuracy of the final leak point. Finally, based on the Lab VIEW program development environment developed by National instrument (NI) Company, the main part of pipeline leak detection system is developed. The system has the advantages of wide practicability, convenient operation and high positioning accuracy. At the same time, the system can also be applied to other oil and gas pipeline leakage detection and location.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE973.6

【参考文献】