Research On Negative Pressure Wave Gas Pipeline Leak Location Method Based On VMD

Nowadays,with the continuous extension of the length of high pressure natural gas pipelines in China,the probability of pipeline leakage accidents also increases.Once the pipeline leakage accident occurs,it will not only cause serious damage to people’s lives and property,but also seriously pollute the surrounding natural environment.Therefore,when the leakage occurs,if the leakage location of the pipeline can be quickly and effectively detected,and the corresponding remedial measures at the leakage point can be taken in time,so as to minimize the loss and harm caused by pipeline leakage.In recent years,pipeline leakage detection and location based on negative pressure wave has become a research hotspot.This method has low research cost,does not need to establish a complex pipeline mathematical model,and its leakage detection efficiency is relatively fast,which can effectively deal with the actual pipeline leakage suddenly occurred in the scene.On the basis of theoretical analysis,corresponding simulation calculation and actual test are carried out in this paper.The research content based on VMD location method is as follows:Firstly,according to the basic position formula effect of negative pressure wave pipeline leak detection precision,the main factors according to the gas flow exist basic control equation of the pressure in the gas pipeline and the temperature distribution along pipeline formula derivation,the pressure and temperature considering the flow formula of gas pipeline and pipeline in negative pressure wave propagation velocity formula.Secondly,the noise contained in the negative pressure wave signal of the collected natural gas pipeline will affect our analysis of the signal,which will have a negative impact on the subsequent judgment of pipeline leak location,so it is necessary to take denoising processing for the signal.In this paper,based on the study of the basic theory of VMD and its effect on signal Decomposition.Aiming at the difficulty in selecting effective Intrinsic Mode functions(IMF)after VMD decomposes signals,a method combining VMD with Orthogonal values(VMD-OV)was proposed to select effective IMF.The effective IMF was reconstructed to obtain the denoised signal.Before using VMD to decompose signals,parameters of the algorithm need to be set.If unreasonable parameters are set,the decomposition effect will be affected.To solve this problem,this paper uses optimization algorithm to optimize the parameters of VMD algorithm.Firstly,the Beetle Antennae Search(BAS)algorithm is improved,and then it is used to optimize the parameters of VMD algorithm to achieve better decomposition effect.Finally,using multi-scale wavelet moment to capture the negative pressure wave signals the start of the spill point,namely the negative pressure wave signal sudden drop point,using the method to get the leakage point on both ends of the negative pressure wave to the upstream and downstream pressure sensor of time,the reuse after the Simpson integral formula and binary search method to solve the pipeline leak positioning formula,locate the leak point,and using the negative pressure wave leakage signal data collected from the laboratory to verify the positioning effect.