Table of Contents
ISRN Applied Mathematics
Volume 2013, Article ID 981692, 8 pages
Research Article

Nonlinear Second-Order Model and Equilibrium Point Characteristic Analysis of DC Traction Power Supply System

1School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
2College of Information Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China

Received 21 April 2013; Accepted 9 June 2013

Academic Editors: E. Kita and H.-T. Yau

Copyright © 2013 Y. H. Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


According to the different features of the DC traction network transient current in the Metro, the electromagnetic transient process of traction power supply system that should be divided into the two forms of short-circuit fault and the low-frequency oscillation was proposed. While traction network short-circuit fault happens, the system model is a weakly nonlinear first-order differential equation, which feeder current is increasing exponentially and eventually stabilized. While the load current becomes low-frequency oscillation current, the system model is a nonlinear second-order differential equation. After linear processing in unique equilibrium point neighborhood, the state space equation of linear system is built, and the structural reason of low-frequency oscillation is revealed by eigenvalue analysis method. The simulation result shows that the simulation current waveforms are consistent with the recorded current waveforms and the division of transient process is reasonable.