Study of effects on power system relay protection by harmonic and negative sequence components of electrified rails

The traction power supply system of electrified railway will cause harmonic and negative sequence current when connecting to the common power net. The propagation characteristics of harmonic and negative sequence current are studied by analyzing a certain power network in the ETAP software, and then the effects on the actions of power relay protection including line protection, bus protection, transformer protection and generator protection by the propagation characteristics are studied, which provides references for the power grid planning.