A Technique for Estimating Line Parameters of Rail Model based on Three-dimensional FDTD Simulations

抄録

The objective of this study is to synthesize a distributed-parameter line model of rails, which have sleepers and a ballast bed, for a surge simulation by means of circuit analysis. The model is composed based on simulation results by Finite-Difference Time-Domain (FDTD) method to take into account a complex configuration of the rails. The transient voltages calculated by FDTD method are approximated by analytical functions. It enables an analytical time-to-frequency transformation without numerical error. The line parameters including frequency dependent effect are derived from the results. The characteristic impedance is inductive due to the ballast bed and sleepers. Influences of the permittivity of the sleepers is observed on the wave propagation characteristic as well as the characteristic impedance. The accuracy of the proposed model for the circuit analysis is confirmed by a comparison with FDTD simulation result of a circuit with a simplified impedance bond model.