Spectrum Analysis of Rail-To-Ground Transition Resistance Based on Lossy Transmission Line Theory

The transitional resistance between the railway track and the ground is an important factor affecting the magnitude of stray currents. In order to explore the spectral detection method of transitional resistance, a spectral response method based on the theory of lossy transmission lines is proposed. Firstly, the distributed parameter model of the track is established under the transmission line theory. Then, the analysis is conducted on the proportion selection of the attenuation distance of the excitation source in the transmission line model. Subsequently, the frequency characteristics of different lengths of the transitional resistance are studied. Finally, the influence of the transitional resistance on the voltage amplitude, current amplitude, impedance magnitude, and voltage-current phase difference along the transmission line model is analyzed. It is found that when the transition resistance value is small, the voltage and current amplitude decay faster, and the impedance value and phase difference are basically unchanged. When the transition resistance is large, the amplitude of voltage and current oscillates periodically, and the impedance mode and phase difference also oscillate, providing a reference for the spectral detection method of transitional resistance.