Research On Leakage Localization Gordian Technology For Long Distance Crude Oil Pipeline

Leakage accidents in pipeline transportation occur frequently in recent years which not only cause great loss of material, but also pollute the environment; what's more, it may even lead to serious casualties. So how to make the effective detection and accurate localization for pipeline leakage is an important work which could help maintain safe running of pipeline transportation. The research on pipeline leakage localization is carried out based on a certain heat oil transported pipeline system in this dissertation, and the main efforts accomplished can be summed up as following:1. The crucial technologies in leakage localization are analyzed. Based on the mode that substation is controlled by the main station, the method of invariable hysteresis time compensation and change variable hysteresis time compensation to invariable hysteresis time compensation is realized according to different modes of the data communication, which makes the sample data of the first station and the end station be processed at the same time.2. The adaptive threshold value method of eliminating the noise is applied to preliminary process of the sample signal. Taking account of the characters that the wavelet transform can detect signal singularity, the discrete wavelet transform is applied to get the featured inflection point of negative pressure wave. A method of adjusting the wavelet decomposes progression which is based on the signal noise ration is put forwarded and the primary research on it carried out.3. The effect of crude oil temperature on the velocity of negative pressure wave in the oil pipeline was analyzed, and a fitting function between the velocity of negative pressure wave and temperature is put forward. A specific function between the velocity of negative pressure wave and the distance is presented by investigating the characterization of crude oil temperature changed along the long distance heated oil pipeline.4. Based on the velocity change of negative pressure wave along the long distance heated oil pipeline, the leakage localization area is confirmed by the mathematic illation; searching and numerical integral method is applied to localize the leakage point. Based on the mathematic model of the long distance heated oil pipeline leakage localization, a new function for leakage localization is put forward, which can improve the efficiency of localization algorithm and real-time ability of pipeline leakage detection system and guarantee localization accuracy.5. A real-time automatically supervision and localization system for the leakage in the long distance crude oil pipeline is designed with virtual instruments. The accuracy and reliability of the system have been proved through long-playing working of the system which is fixed on the field.