Dynamic simulation of rail potential considering rail skin effect

•Measurements are performed on P60 rail over an extended frequency range (50 Hz to nearly 3 kHz) at 20A currents, so that skin effect phenomena are clearly visible. The parameters of the P60 rail equaled to a tubular conductor model are determined.•A foster equivalent circuit of the rail considering the skin effect is constructed. Measure P60 rail in the extended current amplitude range (100A to nearly 600A 50 Hz), the correctness of the model is verified by finite element method and measured results. The DTS’s structure is decoupled in the reflux system model.•The simulation models of the reflux system are built. Compared with the equivalent DC resistance and the 1st-order RL circuit of rail, the simulated rail potential by the foster equivalent circuit is closer to reality. The model can also more accurately predict the actual operation of OVPD. Compared with the equivalent the 1st-order RL circuit and DC resistance, the rail potential results of the modified equivalent circuit of the reflux system are significantly improved.•The dynamic simulation model included the cases of multi-trains, multi-stations, and OVPD actions is applied. The current injected into the rail contains is rich in 1 ∼ 50 Hz components and some sextuple harmonic components. Due to the skin effect of the rail and rail impedance frequency characteristics, the sextuple harmonic current component has a hazardous impact on rail potential. The simulation results of the DTS can accurately predicate the rail potential. The existing simulation of rail potential only considers the equivalent DC resistance and 1st-order RL circuit of a rail. However, the rail current contains a large number of harmonic components, which greatly affects the calculation of rail potential. To accurately calculate the rail potential, the rail is equivalent to a tubular conductor considering the skin effect. The improved equivalent circuit of reflux system is established by vector fitting method (VF), and the 8th-order foster equivalent circuit of rail is built. The dynamic simulation model considering multi-trains, multi-stations, and over voltage protection device (OVPD) actions is established. By measuring the actual internal impedance of the rail, the parameters of the equivalent tubular conductor model of the rail are fitted with the least square method. The maximum error between VF method and finite element simulation, field test results is 6.531%, and 7.271%, respectively. Compared with the equivalent of th