Increasing the operation stability of the remote protection of an ac traction system

The stable operation of AC railway catenary feeder protection depends on the accurate identification of its operation modes. Under existing conditions, the intensity and volume of heavy trains on the Russian railway network is growing rapidly, which causes frequent malfunctions of catenary feeder protection in the normal mode. This leads to disruptions in train schedules and to significant material damage. This paper is devoted to optimizing the algorithm of distance-based catenary feeder protection in AC traction power supply system (25 kV, 50 Hz), which prevents the protection’s incorrect action in the load mode. Based on full-scale currents and voltage oscillograms of catenary feeders for load and short circuit modes, their harmonic compositions are analyzed. A new distinctive feature of the short circuit mode in the AC traction power system was identified as a result of harmonic analysis. The changes of harmonic components during transient processes in load and short circuit modes are presented in graphical form. A new algorithm and a functional scheme of a distance-based catenary feeder protection are proposed. This makes it possible to avoid excessive action of catenary feeder distance-based protection, taking into account the presence of increased current loads.