Uniform Chain Circuit Model for Traction Networks of Electric Railways

A uniform chain circuit model was built for various electric power feeding systems of AC electrified railways. All electrical elements in the traction network, including the short circuit and the conductor break fault, were described conformably by a serial element or a shunt element. According to the chain circuit structure, the mathematical model of the whole network can be assembled conveniently using the nodal admittance matrices of elements. Considering the relatively large leakage conductance of the return circuit to the ground, the multiphase equivalent π-circuits were adopted for the uniform multi-conductor sections of the traction network. The characteristic admittance matrix, which can be calculated by the phase-modal transformation method, was introduced for the truncation treatment at terminals of the feeding system. The proposed mathematical model provides a base for calculating the power flow, i.e. the voltage and current distribution of the traction network under certain load conditions. This model can also be used in researches such as the steady state short circuit calculation and the harmonic resonance analysis.