High Resolution Planar Eddy Current Coil Inspection Technology Based On Pipeline Inspection

Pipelines are the lifeline of a country’s energy system,and pipeline transportation is the primary mode of transportation for important energy sources such as petroleum and natural gas.The increase in the scale of domestic oil and gas pipeline networks and the exploration and development of major oil and gas fields indicate the rapid development of pipeline transportation.However,as pipeline service time increases,soil environmental corrosion and safety hazards during pipeline production may cause harm to pipelines and lead to significant safety issues.Therefore,regular inspection and maintenance of pipelines are necessary to ensure their safe operation.This thesis focuses on defect detection and evaluation of small-diameter oil and gas pipelines.Considering that pipeline leak magnetic detection takes up a large volume of space and existing eddy current detection data is limited and has weak defect resolution capabilities,various single excitation and multiple receiver differential planar coil models are proposed based on eddy current detection.The defect resolution capability is improved by generating eddy currents with a single excitation coil and enhancing the response of defects through multiple receiver coils,and this is verified through simulations and experiments.The main research work is as follows:(1)Based on the principle of electromagnetic induction and equivalent circuit model,various single excitation and multiple receiver differential planar coil models are proposed through differential structure to improve defect detection sensitivity and through single excitation and multiple receiver planar structure to improve defect resolution capabilities.The eddy current characteristics and defect signals of each model are simulated and analyzed using COMSOL Multiphysics to demonstrate their improvement in defect resolution capabilities.Simulation comparisons are performed on important parameters to improve detection sensitivity,and simulations of various defects are performed on coil models to verify their detection capabilities.Various coil models are processed and proposed,and an experimental platform is established in the laboratory to perform experimental verification of different specimens using various coil models for pipeline inspection.(2)An integrated pipeline inspection system is designed,including signal excitation module,data acquisition module,data storage module,power management module,etc.The actual pipeline tensile experiment is performed using an internal detector,and the detection capabilities and defect resolution capabilities of various coil models are verified through pipeline experiments.Due to the hardware complexity and power consumption of multiple detection coils,the idea of neural network optimization is used for reference,and the physical model is optimized by convolving the coil signals to synthesize multiple signals into a single signal.An algorithm model is designed,and its effectiveness is verified in the laboratory platform preliminarily.