Applied Research Of Virtual Instrument Technology In Pipeline Leakage Fault Diagnosis

With the development of the industrial process, oil resources are strongly depended on by all the countries in the world, while oil pipeline security are also becoming increasingly prominent. pipeline leakage accidents were often caused by the criminal stealing and pipeline corrosion, resulting from the economic losses as high as tens of billions each year. Therefore, for improving the management of pipeline conveying, reducing the economic losses and environmental pollution, it is importantly and practically significant to strengthen the pipeline leakage detection and location technology research. The relevant scientific literature and materials are extensively checked up in this paper, for domestic oil pipeline leakage detection technology status and previous research results, then a leakage signal denoising and preprocessing method of fusion algorithm of Fast ICA blind source separation and wavelet threshold denoising is proposed, the correlative analysis and the principle of negative pressure wave to determine the leakage position are also supported. Meanwhile, using LabVIEW virtual instrument technique to build an fault diagnosis system of pipeline leakage, the hardware and software of this system are designed in the paper. Finally, by a large number of simulation experiments and experiments of practical leakage signal processing the system performance are tested. The results of concrete work and research are as follows:(1) A specific application of pipeline leakage location based on the correlative analysis and the negative pressure wave are described in the paper. According to the relevant signal processing theory and the principle of pipeline leakage detection and location, choosing the pressure wave signal which is caused by oil pipeline leakage as the research object, and performing the pipleline leakage detection and location through making the signal collected by the sensor conduct the correlative analysis. Meanwhile, selecting the peripheral hardware devices for the detection and location system of oil pipeline leakage, including the choices of pressure transducers and signal conditioning equipment, data acquisition card of selection. What's more, taking advantage of LabVIEW as a software development platform.(2) A method of fusion algorithm of Fast ICA blind source separation and wavelet threshold denoising is proposed, while establishing the denoising model and discussing the method of de-noising process. To some extent, traditional wavelet thresholding (hard, soft threshold method) de-noising has always existed its own limitation, denoising result is not satisfactory. Thus, under the basic wavelet thresholding function two methods of fusion algorithm are used to conduct the leakage signal denoising and preprocessing in this paper, which are based on the analysis of reasoning by building a wavelet multi-algorithm fusion threshold function, and combined with Fast ICA blind source separation to separate signal and noise, then it can also effectively improve the leakage of the signal denoising effect and overcome the shortage of traditional wavelet threshold denoising. Besides, the effectiveness of the algorithm is proved by a large number of the simulation and experimental analysis.(3) Making use of Lab VIEW virtual instrument technique to design a detection and location system of pipeline leakage, which can achieve the positioning-alarmed function in the pipeline leakage.The main contents including:friendly interface, on-site data acquisition, data communication, signal denoising processing, alarm and location of pipeline leakage. Meanwhile, analysing and testing the denoising preprocessing and positioning-alarmed module in this system by inputting the simulation signal. Making the on-site acquisition signal of pipeline leakage input to the system to verify the overall system performance, and the correctness and feasibility of this system is eventually proved.