Application Of Acoustic Signal In Pipeline Leakage Monitoring Based On ?-OTDR System

The application of acoustic signal based on ?-OTDR system in pipeline leakage monitoring in recent years,due to the aging of pipeline,man-made damage,natural disasters and other factors,oil and gas pipeline leakage accidents occur frequently,which not only poses a certain threat to the safety of people's lives and property,but also pollutes the environment.Therefore,the research on pipeline leakage detection technology is of great significance.?-OTDR(phase sensitive optical time domain reflectometer)distributed optical fiber vibration sensing system has the advantages of continuous distributed measurement,high sensitivity and long measurement distance,which is very suitable for oil and gas pipeline leakage detection.In this thesis,on the basis of the?-OTDR system,the acoustic signal of the pipeline is monitored,and the BP neural network is used to analyze and identify the acoustic signal of the pipeline leakage,The main content of the thesis includes:(1)Based on the principle of optical fiber scattering,the OTDR and OTDR technology are introduced.On this basis,the structure and principle of the distributed sensing system of?-OTDR are described,and its important performance indexes are analyzed.(2)The basic process of pipeline leakage sound signal processing is studied.The leakage sound sample signal is preprocessed,and MFCC(Mel frequency cepstral coefficients)feature extraction is performed on the preprocessed pipeline leakage sound signal.Noise interference is inevitable in the actual pipeline leakage monitoring,to solve this problem,a new wavelet threshold denoising method is proposed in this thesis,which can achieve better denoising effect on acoustic signal.(3)The process of pipeline leakage signal recognition based on monitoring is studied.Firstly,the process of acoustic monitoring is described,and then the principle of neural network is described.Finally,the BP neural network pipeline leakage model based on monitoring is established,which can identify the leakage acoustic signal samples.This method has good leakage identification effect,which verifies the feasibility and reliability of pipeline leakage identification technology based on monitoring,and provides a theoretical basis for oil and gas pipeline leakage monitoring basis.