scholarly journals An Improved Negative Pressure Wave Method for Natural Gas Pipeline Leak Location Using FBG Based Strain Sensor and Wavelet Transform

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Qingmin Hou ◽  
Liang Ren ◽  
Wenling Jiao ◽  
Pinghua Zou ◽  
Gangbing Song

Methods that more quickly locate leakages in natural gas pipelines are urgently required. In this paper, an improved negative pressure wave method based on FBG based strain sensors and wavelet analysis is proposed. This method takes into account the variation in the negative pressure wave propagation velocity and the gas velocity variation, uses the traditional leak location formula, and employs Compound Simpson and Dichotomy Searching for solving this formula. In addition, a FBG based strain sensor instead of a traditional pressure sensor was developed for detecting the negative pressure wave signal produced by leakage. Unlike traditional sensors, FBG sensors can be installed anywhere along the pipeline, thus leading to high positioning accuracy through more frequent installment of the sensors. Finally, a wavelet transform method was employed to locate the pressure drop points within the FBG signals. Experiment results show good positioning accuracy for natural gas pipeline leakage, using this new method.

2018 ◽  
Vol 119 ◽  
pp. 181-190 ◽  
Author(s):  
Qiang Chen ◽  
Guodong Shen ◽  
JunCheng Jiang ◽  
Xu Diao ◽  
Zhirong Wang ◽  
...  

Author(s):  
Dongliang Yu ◽  
Likun Wang ◽  
Bin Xu ◽  
Hongchao Wang ◽  
Min Xiong ◽  
...  

Pipe is a very important tool for long-distance transportation of nature gas. In the long-term running, there will be inevitably an appearance of a rupture, leak or damage usually caused by manmade event or by nature disaster. Leaks may generate dangerous clouds of gas escaping from the high-pressure pipe and produce serious incidences involving fire and explosion endangering the life and property safety of people in and around the area. Monitoring of natural gas pipeline leaks will timely find out and locate these dangerous occurrences and reduce loss. Within the leak monitoring, the core contents are the accurate location of leaks as well as the rapid identification of different signal sources reducing false alarm ratio. Once a leak occurs, the supersonic jet of escaping gas can generate a non-linear & chaotic negative pressure wave signal based on static pressure measurement and an acoustic signal based on dynamic pressure measurement [1]. By properly interpreting these two kinds of signals together, it is possible to detect and locate the leak along the pipe. However, useful signals usually mix in the powerful backdrop signals and noises. In order to resolve the problem, the wavelet packet decomposition technique [2] is used to reduce the noises and get the feature signals of negative pressure wave and acoustic wave. Furthermore, a lot of different condition regulating signals for instance compressor start-stop, valve adjusting and gas turbulence can interfere with the accurate identification of leaks and result in false alarm. It is quite required to classify these similar signals. Thus, BP neural network [3] is used to quickly recognize the different pressure fluctuation signals. Finally, an integrated system developed by LabView is introduced to timely monitor the operation condition and locate the leak. Field tests indicate this system using negative pressure wave method, acoustic wave method, wavelet packet decomposition technique as well as BP network has a good effect.


Author(s):  
Zhuang Li ◽  
Shijiu Jin ◽  
Likun Wang ◽  
Yan Zhou

The petroleum leakage has been a serious problem these years in China. The leakage, mostly caused by human destruction, lasting a short time with a large amount of loss, is not only an economic loss for the petroleum company, but environmental pollution, a public issue. Thus a monitoring system, which can identify the leakage and locate the leak point in real time, is required. One of the challenges is the sensitivity of the system. The system is expected to respond quickly to locate the point so that the security personnel can find and mend the orifice in time. Another challenge is the accuracy of the locating result. Because of the features of Chinese petroleum: high viscosity, high wax content and high freezing point, the sound wave speed in the oil is not a constant along the pipeline and the leak point calculated by the traditional negative pressure wave method are invalid. In this paper, a modified negative pressure wave method was put forward according to the variation of the wave speed. A wavelet-based algorithm applied to calculate the leak point gives fairly satisfied results. The data acquisition, signal processing and the structure of the pipeline leakage monitoring system (PLMS) were analyzed. The system has played a big role on the pipeline network in Shengli Oil Field and long pipelines of East China Oil Bureau.


2017 ◽  
Vol 865 ◽  
pp. 580-585 ◽  
Author(s):  
Chen Ding ◽  
Guo Dong Wu ◽  
Liu Peng ◽  
Guang Ming Cao ◽  
Gou Zhao ◽  
...  

Negative pressure wave positioning method is a technique for pipeline leakage detection and location, which is widely used in various fields. Wireless sensor technology has the advantages of low power consumption, easy networking and high positioning accuracy, which is the preferred technology for wireless location. This paper discusses a pipeline monitoring system based on negative pressure wave and wireless sensor. This system combines the advantages of high positioning accuracy, wide application range and small nodal volume. In order to prove the practicality, reliability and accuracy of this system, experimental results and comparison with other method are given, positioning error within 5%.


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