Measurement-Based Wideband Model and Electric Parameter Extraction of Railway Traction Power System

Harmonic resonance and power instability issues plague the operation of the traction power system (TPS). Establishing effective models with the correct parameters is widely accepted for analyzing such problems. However, it is still a challenging task for gaps between models and actual scenes. This article proposes an adaptively intrinsic parameter extraction methodology for TPSs based on wideband impedance measurement. An adaptive equivalent parameter model representing the TPSs is established after determining the impedance characteristics of each frequency region. The sensitivity index to the measuring impedance from different schemes is estimated through test data. Also, the measurement scheme is determined, which only needs to inject twice wideband excitation signal into the system at two connection points and measure three pairs of voltage and current sampling signals. The intrinsic parameters extracted are calculated from the adaptive equivalent model and the wideband impedance measurement results. The proposed method can be added to the existing measurement algorithms. It can provide accurate equivalent parameters and guidance for efficient model building. RTLab-PHIL experimental results show that the proposed method yields good parameter extraction and that it can also adapt to changes for various railway TPSs.