Reduced multiconductor transmission line models for power quality analysis in railway systems

The goal of this work is to present and discuss two methods to effectively represent the MTL with a reduced number of conductors in case of groups of wires shorted together and/or grounded. Reducing criteria are applied to the MTL cells that represent the 2×25 kV-50 Hz AC high-speed railway electrification system, also including the high voltage grid that supply the Electrical Substation. The obtained models are used to evaluate the disturbances on the track circuits caused by trains harmonic current injection. The numerical results are reported, compared and discussed.