What places are DC screens generally used in?

DC screen is an important electrical equipment, so which places are DC screens generally used in? 

The power operation power sources used in power plants and substations are currently DC power sources, which provide power for controlling loads, power loads, and DC emergency lighting loads, and are the foundation of contemporary power system control and protection. The DC screen consists of an AC distribution unit, a charging module unit, a step-down silicon chain unit, a DC feeding unit, a distribution monitoring unit, a monitoring module unit, and an insulation monitoring unit. It is mainly used in small and medium-sized power plants, hydropower stations, various substations, and other users who use DC equipment (such as petrochemicals, mines, railways, etc.) in the power system. It is suitable for switch opening and closing, as well as instruments, meters, relay protection, and fault lighting in secondary circuits. DC screen is a new type of digital control, protection, management, and measurement DC system.