The invention relates to an electrified railway digital traction substation automation system. The system comprises a station control layer, an interval layer and a process layer. The system is characterized in that the integrated monitoring host of the station control layer is provided with intelligent substation monitoring software, the devices of the interval layer are connected and communicatewith one another through GOOSE, and therefore, networked protection and the reorganization of a power supply system can be realized; the process layer configures intelligent components for intelligent primary devices/primary devices; the intelligent primary devices are electronic transformers, intelligent switches, and intelligent transformers; and the intelligent components include a JDA-331U voltage merging unit, a JDA-331M merging unit, a JDA-331C intelligent terminal, a JDA-331 merging intelligent unit, and a JDA-332 transformer body intelligent unit. According to the electrified railwaydigital traction substation automation system of the present invention, the intellectualization of traditional primary devices is realized through the intelligent components; the intelligent primary devices are supported; hierarchical locking logic is realized in a traction substation; and the complete logic locking of the station control layer and the interval layer is combined with the electrical locking of a mechanism, so that complex logic locking requirements can be satisfied.