Systematized short-circuit analysis of a 2×25 kV electric traction network

Abstract

Abstract This paper presents a systematic approach for short-circuit analysis of a 2×25 kV electric railway system. This approach uses a full-scale model of a 2×25 kV electric traction network. The model is composed of a substation model, autotransformer (AT) models, and network conductor models. The substation model considers the three most commonly used connection schemes of traction transformers. There are single-phase, V and Scott connections. The AT model considers the impedance and inherent characteristics of the AT, while the network conductor model considers the self and mutual impedances of three major conductors in a traction network (overhead contact wire, return feeder and rail). These models are all in coupling-free type. Therefore they can be easily implemented into a self-developing program or commercial packages, such as a short-circuit program in phase coordinates, the Electromagnetic Transients Program (EMTP), or the Personal Computer Simulation Program with Integrated-Circuit Emphasis (PSPICE). With the proposed models, a short-circuit analysis program is developed by the node admittance matrix method. In this manner, the fault currents in each branch in a traction network as well as the curves of fault currents versus fault location can be easily achieved. Furthermore, the voltages at the overhead contact wire and return feeder along a railway route can be calculated if required.