SYSTEMATIZED SHORT-CIRCUIT ANALYSIS OF A 2 X 25 KV ELECTRIC TRACTION NETWORK

This paper presents a systematic approach for short-circuit analysis o f a 2 x 25 kV electric railway system. This approach uses a full-scale model of a 2 x 25 kV electric traction network. The model is composed of a substation model, autotransformer (AT) models, and network condu ctor models. The substation model considers the three most commonly us ed connection schemes of traction transformers. There are single-phase , V and Scott connections. The AT model considers the impedance and in herent characteristics of the AT, while the network conductor model co nsiders the self and mutual impedances of three major conductors in a traction network (overhead contact wire, return feeder and rail). Thes e models are all in coupling-free type. Therefore they can be easily i mplemented 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 m atrix method. In this manner, the fault currents in each branch in a t raction network as well as the curves of fault currents versus fault l ocation can be easily achieved. Furthermore, the voltages at the overh ead contact wire and return feeder along a railway route can be calcul ated if required. (C) 1998 Elsevier Science S.A. All rights reserved.