Wide-Band Oscillation Analysis of Railway Power Conditioner-Network-Train Coupling Power System Considering Energy Flow Modes

Railway power conditioner (RPC) is one of the most effective devices in electrified railways for the compensation of negative sequence, reactive power and the utilization of regenerative braking energy. However, the access of RPC will make the railway power supply system exhibit different energy flow modes, which will render the existing principles about wide-band oscillation characteristics opaque (low-frequency oscillation and high-frequency resonance), and increase the difficulty of analysis. The objective of this paper is to present a comprehensive analysis of the wide-band oscillation issue in the RPC-network-train coupling system. Initially, based on the dq decomposition method and mirror-frequency method, a unified impedance model for the system is established considering diverse energy flow modes. Subsequently, the wide-band oscillation distribution is obtained based on the modal decomposition method, thereby revealing the coupling mechanism between the RPC and the existing railway system. The security domain is delineated by further locating the key components affecting the wide-band oscillation based on the sensitivity of the parameters to the frequency and amplitude of the oscillation. Finally, the correctness of the analysis result is verified on the simulation platform and StarSim hardware-in-the-loop experimental platform.