JUSTIFYING THE USE OF THE EARTH AS ONE OF THE POWER PHASES FOR A 25/0.4 KV TRANSFORMER SUBSTATION OF THE AGRICULTURAL POWER SUPPLY SYSTEM

The paper presents the results of studying the operating modes of a 25/0.4 kV agricultural power supply transformer substation fed from the AC railway network via the “two additional conductors – a rail” system and the substation grounding circuit. The study focused on the standard operating mode that uses a rail as the third phase as well as forced and modified operating modes that use the earth as a current-carrying conductor. The authors looked into the possibility of using the earth as the third phase conductor for supplying the current to the transformer substation and thus preventing agricultural consumer outages due to railway repairs. In addition, the study considered issues of power supply quality and electrical safety to ensure operation of a 25/0.4 kV transformer substation in forced and modified operating modes.