Harmonic and inter-harmonic analysis on power signal from railway traction systems

The railway traction system is a non-linear system including a large number of electrical facilities. Analyzing the signal emitted from the system can facilitate the failure diagnosis and evaluate the power supply system's performance. The power supply system's electric signal contains a wide range of unintended harmonics and inter-harmonics, which degrades the system's performance. This paper develops methods to identify the harmonic and inter-harmonic components hiding in the power signal by considering it as a regression problem. It derives explicit expressions to represent the signals collected in the field. That expression can be used for further failure diagnosis. Simulations are proposed to investigate the significance of transmitting line's mutual interference and use of autotransformers to the performance of the traction power system.