Research On Gas Pipeline Leak Location Technology Based On VMD

Pipelines are important transport carriers for water,oil and natural gas,and play an irreplaceable role in daily life and industrial development.However,due to the aging of the pipeline caused by the long-term use,the corrosion of the transport medium,the rupture caused by the long-term burial in the ground,and the damage of the lawless elements,the pipeline leakage will be caused.Once a leak occurs,if it is not repaired in time,it will cause property loss and waste of resources,and endanger people’s lives.Therefore,the accurate location of the leak point of the natural gas pipeline becomes very important.This paper analyzes the key points and difficulties in the pipeline leakage location problem,studies the signal noise reduction processing,time delay estimation and leak point location and other key technologies,and proposes a method to complete the location of the pipeline leak point by detecting the acoustic wave signal of the pipeline leak.method.The main work is as follows:First,in-depth study of the algorithm principle and theory of Variational Mode Decomposition(VMD),and then the simulation analysis of the common noise signal and sawtooth signal in the process of signal processing,and the wavelet decomposition,empirical mode decomposition Compared with Empirical Mode Decomposition(EMD),it proves that its decomposition ability is stronger,and it also verifies that the VMD algorithm can be used for natural gas pipeline leak detection.Secondly,the signal denoising method based on improved VMD is studied.For artificially setting the decomposition level K and penalty factor of VMD algorithm α Inaccurate will affect the decomposition ability and decomposition effect.An improved adaptive variational modal decomposition algorithm is proposed,that is,the improved chimp optimization algorithm(chimp)based on particle swarm optimization and chaotic mapping is used to search the decomposition layers K and penalty factor of VMD α Two key parameters,the obtained parameters are used as the preset value of VMD for modal decomposition.The Hausdorff distance(hd)is used as the method to screen the effective modes after VMD decomposition.The effective signal components are screened and reconstructed.The comparison with other methods shows that the proposed method can improve the signal decomposition ability and achieve good denoising results.Thirdly,in view of the problem that the noise will make the signal delay estimation error larger,a generalized quadratic cross-correlation delay estimation method based on VMD is proposed.This method can effectively remove the interference factors in the noisy signal after the preprocessing of the improved VMD.Therefore,the accuracy of signal delay estimation is improved.The generalized quadratic cross-correlation delay estimation algorithm is used to estimate the delay of the signal.Compared with the traditional method,the experimental verification shows that the proposed method has higher delay estimation accuracy and better stability.Finally,using the signal denoising algorithm and time delay estimation method proposed in this paper,combined with the propagation velocity of the medium in the pipeline to locate the leak point,the pipeline leak location model is constructed.Experiments show that this method can effectively reduce the positioning error and help to improve the accuracy of pipeline leakage positioning.