Calculations of Leakage Impedance of Rail to Earth in Ballastless Track by Finite Element Method

Abstract

The leakage resistance of rail to earth is an important parameter of electrified railways, which directly affects the characteristics of traction return current and railway signal track circuit. The ballastless track usually has a much larger value for the leakage resistance of rail to earth compared to ballasted track. In addition, its distributed capacitance effect of rail to earth should not be ignored. The rail has an anharmonic cross-section, and is installed on the spacing support of the concrete integrated ballastless bed in ballastless track structure. The leakage impedance of rail to earth cannot be calculated using a practically simple theory or method, such as the model of thin circular conductor of overhead transmission lines. This paper presents the test and calculation results of the rail leakage impedance in Jin–Qin (Tian jin city–Qin huangdao city) high-speed railway of China. The finite element model is established by using the Comsol Multiphysics simulation software. Comparison of the calculated and measured results shows that the finite element model for calculating the leakage impedance of rail to earth is an effective approach. The field measured data can be used in the future for the related analysis and calculation of traction networks and track circuits.