Today, direct current (DC) power sources are used for electrical operations in power plants and substation transformers, providing power for controlling loads, motive loads, and DC emergency lighting loads, serving as the foundation for contemporary power system control and protection. The DC screen is composed of a transformer subunit, a charging module subunit, a step-down silicon chain subunit, a DC distribution subunit, a distribution monitoring subunit, a monitoring module subunit, and an insulation monitoring subunit. It is primarily applied in small and medium-sized power plants, hydropower plants, various substation transformers, and users of DC equipment such as petrochemical, mining, and railway industries. It is suitable for switchgear operations, instruments, meters, relay protection, and emergency lighting in secondary circuits. The DC screen represents a new type of digital control, protection, management, and measurement DC system.