The Development Of The Real-time Detection System For Oil Pipeline Leak Based On LabVIEW

The leakage accidents of the oil pipeline not only lead to huge economic loss to the enterprises, but also pollute the environment. So it is of great importance to design an effective system to detect and position oil pipeline leak. The paper accomplished the development of real-time detection system for oil pipeline leak based on LabVIEW combined sensor technology, digital signal processing technology and communication technology.In this paper, the common methods for leakage detection have been researched. The paper compared the advantages and disadvantages of each method. While making the general consideration toward the actual situation of DAQING oil factory, the pressure combined with flow method for detecting leakage and the negative pressure wave method for locating leakage were proposed. Firstly, this paper described the principle of the negative pressure wave location, because the false positive rate of system only based on negative pressure wave method will be higher in different conditions, so it is necessary to make sure whether there is a leakage on the pipeline firstly so that the system can position the leakage of pipeline by the negative pressure wave method when leak happens. Secondly, this paper described and solved the key technical problems during building the system; include building the wireless data communication net by the spread spectrum technology, the synchronization problem between the stations in system and the mathematical formula of the negative pressure wave speed. The paper solved the synchronization problem via software method; it is accomplished by matching the time of one station plus the time delay during the transportation with another one. Though Timing Synchronization is less precise in comparison with the traditional GPS time service, it provides the approaches with lower cost. The paper gave the mathematical relationship between the negative pressure wave speed and the temperature of oil, and analyzed the changes of temperature along pipelines, and then built the linear correction model of the negative pressure wave speed, the precision of the system location has been improved.The part of the data process, which will affect the accuracy of distinguishing and positioning the leakage, is significant to the whole system. The wavelet analysis has more advantage on processing the non-stationary random signals than the traditional Fourier transform, so the wavelet analysis processed the signals is a better choice. In this paper, wavelet threshold helps to accomplish filtering the noise and find out the best approach to filter the noise by analyzing the Symlets and Daubechies Signal filtering and Feature Points Extraction has been accomplished with the help of MATLAB on the LabVIEW platform.This paper accomplished the selection of the hardware by analyzing the detection methods, and designed all of the modules of the system based on LabVIEW, which proves to be in stable operation in the past year.