Application of spectrum detection technology in rail-ground transition resistance of urban rail transit

The harm of stray current brought by the rapid development of urban rail transit is becoming more and more serious. The rail-to-ground transition resistance is the most important factor affecting the size and distribution of stray current, and it is the key to study the problem of stray current. At present, there is no effective method to detect the rail-ground transition resistance. Therefore, in this paper, by establishing a simulation model of subway rail-drainage network, the influence of transition resistance, soil resistivity and concrete layer resistivity on the impedance amplitude phase-frequency characteristic curve between the rail and the drainage network is simulated and analyzed. The research finds: The change of soil resistivity has no effect on the impedance amplitude-phase-frequency characteristic curve between the rail and the drainage network. The influence of the resistivity of the concrete layer on the impedance amplitude-frequency characteristic curve between the rail and the drainage network is above 300kHz. The influence frequency range of the phase-frequency characteristic curve of the impedance between the grids is above 70kHz; the frequency range of the influence of the change of the transition resistance on the impedance amplitude and phase-frequency characteristic curve between the rail and the discharge grid is 50Hz-IMHz. The method of detecting whether the rail-to-ground transition resistance meets the standard is of great significance to the evaluation and prevention of stray current by using the amplitude-phase-frequency characteristic curve of the impedance between the rail and the drainage network in the frequency section.