Study On Surface Electromagnetic Characteristics Of High-speed Railway Integrated Grounding System

The integrated grounding system provides the equipotential grounding connection for high-speed railways.In recent years,high-speed railways in China have developed rapidly,the increase of operating mileage and the increase of locomotive operating density have put forward higher requirements for the safety of integrated grounding system in high-speed railway.The healthy operation of the integrated grounding system is crucial to the safe operation of the high-speed railways.In this paper,detailed modeling of different parts of the integrated grounding system is carried out,including the roadbed section,the traction substation grounding grid,the bridge section and the tunnel section,and the electromagnetic characteristics of the integrated grounding system for each part were analyzed.The electromagnetic characteristics under fault conditions were studied,provided a theoretical basis for fault location and diagnosis.Based on the CDEGS software platform,the integrated grounding system model for roadbed section was built,electromagnetic distribution characteristics under different working conditions were studied,and fault characteristics were analyzed by setting different fault points.The traction substation grounding grid model was constructed.Under normal conditions,the influence of various factors(soil structure,current amplitude,and current frequency)on the electromagnetic distribution was considered;the degree of fault of the grounding conductors were classified.The electromagnetic characteristics of the single-point fault surface were analyzed;the electromagnetic characteristics of the single-point fault of the grounding grid were analyzed;the electromagnetic distribution of the grounding grid under different frequency conditions was calculated,and the high-frequency fault characteristics of the grounding grid were studied.A model of bridge integrated grounding system was established.The paper fully considered the grounding structure of the bridge and studied the grounding characteristics in detail.Taking the magnitude of the surface electromagnetic along the bridge as the feature quantity,the various faults of the bridge integrated grounding system were analyzed in depth;the results show that: based on the electromagnetic distribution,various fault types and fault locations of the bridge integrated grounding system can be judged.Due to the particularity of the spatial medium structure,CDEGS has disadvantages in the grounding analysis of the tunnel grounding system.In this paper,the finite element method was used to solve the electromagnetic distribution in the tunnel space;in order to better introduce the finite element method into the high-speed railway tunnel grounding system,In this paper,an curved hexahedron element suitable for the tunnel structure was constructed.Then,based on the improved finite element method,the electromagnetic distribution in the high-speed railway tunnel model was calculated.Finally,the grounding fault was analyzed and judged.The dissertation fully considered the grounding structure of each part in the high-speed railway integrated grounding system.The theoretical research and simulation results show that electromagnetic can reflect the fault characteristics of different parts and types of the integrated grounding system,and the results can provide a certain theoretical basis for the fault diagnosis of the high-speed rail integrated grounding system in the project.