Abstract: Through the introduction and analysis of the technical routes of different power systems and the characteristics of different batteries, combined with the development requirements of the DC power system in the current power grid construction, a design scheme of the DC power system for a 220kV substation is proposed to simplify the "1+1" dual power supply configuration.The equipment configuration and calculation are carried out according to the scheme, and the standardized calculation process and calculation formula are formed, which provides a reference for the equipment selection of other similar scale substations.