Low-frequency Oscillation Analysis of Railway Train-Network System Considering the Two Feeding Sections of the Traction Substation Based on Harmonic State-space Modeling

The low-frequency oscillation (LFO) has occurred in electrified railway train-network system. The existing researches mostly establish a single-phase circuit to study the LFO which has the single-phase voltage source, network impedance and the trains. This paper focuses on the dynamic interaction between the two groups of trains which are separately connected to the two feeding sections of the traction substation. Firstly, the harmonic state-space (HSS) model of this asymmetric system formed by trains connected to the two feeding sections, the traction transformer, and the three-phase power grid is derived. Secondly, the system oscillation modes are obtained by eigenvalue method, and the influence of the trains connected to one-side feeding section on the oscillation mode dominated by trains in the other feeding section is studied. Finally, the correctness of theoretical results is verified by simulation in MATLAB/Simulink.