Field Tests for Evaluating the Inherent High-Order Harmonic Resonance of Traction Power Supply Systems Up to 5000 Hz

The inherent resonant frequency of a traction power supply system (TPSS) needs to be accurately identified in order to provide crucial information for resonance suppression, safe operation, and system optimization of electrified railways. In this paper, implementation of experiments was carried out in actual railway systems to evaluate the inherent harmonic resonances of the TPSS. The field tests were based on a harmonic generator (HG) constructed with cascaded H-bridge converters (CHBCs). Compared to other experimental setups, the field tests of this paper, which were performed in the 25kV practical system, can provide straightforward results in a wide frequency range up to 5000 Hz. Such a wide frequency range is necessary for assessing and taking effective measures to address the harmonic resonance problem. The results of this paper will supply valuable data for the modeling of TPSSs and the stability analysis of train converters contributing to improvement of the power quality of electric railways.