Key Technology Research Of Non-Invasive Buried Cable Detection Based On Magnetic Sensing

As urbanization progresses and the underground cabling project advances steadily,the types of urban underground pipelines are increasing and becoming more complex.Buried power transmission lines,as the core carrier of urban energy flow,are crucially important for the management of their network architecture in the city.However,the current management of buried pipeline archives is chaotic,and the geographical data of pipelines is outdated,leading to accidents involving buried pipelines during urban construction,which seriously hinders the efficiency of urban development.Currently,most of the buried cable detection solutions are based on metal pipeline detection schemes,which have low efficiency and accuracy in non-invasive scenarios,and there are no targeted detection schemes for buried power transmission cables.Therefore,this article focuses on the demand for non-invasive and rapid detection of buried cables in urban areas,and designs a noninvasive buried cable detection system based on a three-axis magnetic flux gate sensor,with the frequency magnetic field generated by AC current in the cable as the entry point.The main work is as follows:(1)A non-invasive cable location detection scheme based on magnetic field inversion algorithm is proposed,and two-dimensional models of multiple buried cable laying scenarios are constructed.The twodimensional modeling of XLPE cable is implemented based on the finite element simulation software COMSOL.The space-frequency magnetic field under multiple laying scenarios is simulated based on the relevant parameters of various cable laying scenarios in the National Construction Standard Design Atlas.The modeling and simulation research of multiple cable arrangement modes is carried out to analyze the relationship between the space-frequency magnetic field and the depth of metal pipeline laying,the distance from the cable,and other parameters in the single cable direct burial laying scenario with metal pipeline crosstalk.(2)A buried cable detection scheme based on a magnetic flux gate sensor array is proposed,and the rapid orientation and depth measurement technology of buried cables is studied.The design and development of the detection system and device are completed.A work frequency magnetic field detection system based on a three-axis magnetic flux gate sensor is designed,including the rear-stage circuit of the magnetic flux gate sensor,the DSP circuit,and the corresponding peripheral modules and power supply module.FFT algorithm and IQ demodulation algorithm for signal extraction of the work frequency magnetic field are implemented based on STM32 microprocessor.The encapsulation design of the magnetic flux gate sensor array system is completed.(3)A magnetic flux gate sensor AC signal calibration scheme is proposed,and the mathematical modeling of the main errors of the magnetic flux gate sensor is completed.The system detection performance test is completed in the outdoor urban space,and in the single cable direct burial laying scenario without metal buried objects,the measurement depth error before calibration is 18%,and the measurement depth error after calibration does not exceed 2%.The measurement error of cable orientation at a speed of no more than 0.5m/s and the lateral distance of the measurement error are not more than 0.1m.