Study On Crude Oil Variable Speed Transportation System's Pipeline Leak Detection Technology

The leakage accidents in pipelines transportation not only seriously pollute the environment, but also cause great economic losses. In order to guarantee the pipelines work safely, pipeline leak detection technique must be studied in depth. With more and more use of Inverter in oil pipeline transportation, pipeline transportation becomes non-stationary and pipeline leak detection goes more difficult. Therefore, crude oil pipeline leak detection technique with Inverter system has become an important research topic. For the above, the following work is carried out in this thesis:1. In order to preprocess the leakage data, signal processing method such as Wavelet Transform, EMD Transform, One-dimensional Mathematical Morphology and S Transform are introduced. Abnormal error of processed signal and 50 Hz power frequency interference were analyzed. Wavelet-EMD-morphological model was proposed and effectiveness of the method was demonstrated through analyzing the field signals. LabVIEW was applied to develop practical programs.2. Against the actual system, the energy saving principle of VFD was introduced and the model of pipeline transportation system with Inverter was established. The amplitude-frequency and phase-frequency characteristics of the system was analyzed when used PID control. The field signals and the simulation results were compared and the principle of PID parameter setting and the PID parameter table were given. The plan of solution about frequency transportation was given.3. For pipeline leak detection's critical issues—alerting and locating, three algorithms based on leak signal's amplitude, shape and frequency characteristics about leakage alarm which are the window shift method, S-shaped function and frequency domain analysis were proposed. The method's reliability was verified through the leak-site data processing statistics. Then, the Morphological and S Transform position method were proposed and its position accuracy was compared with the wavelet method. A conclusion that they can alternative wavelet method was obtained.4.Virtual instrument was used to design a crude oil leak auto-detection system,By doing experiments on Multiphase flow experiment loop of the China University of Petroleun and field application the practicality of the system was verified.