The power operation power supply in power plants and substations now adopts DC power supply, and DC screen is used to supply this kind of DC power supply. It provides power for controlling load and power load, as well as lighting load of DC accident, and is the basis of control and protection of modern power system. Modern science and technology, especially the development of computer technology and communication technology, make the power system develop towards the direction of integrated automation, unattended power station and centralized network management. As an important part of power system, DC power supply system (DC screen) can make its own power quality and reliability to automation process. As a result, a large number of advanced science and technology have been applied. It is mainly composed of power input system (AC input), power dual-channel switching system, charger control system, charger, DC distribution system, insulation monitoring system, integrated controller (system monitoring control system, DC screen brain), flash system, communication system, battery and so on. Among them, the integrated controller, dual-channel switching, charger control and the selection of charger are the main links to ensure the reliability of DC screen.

The integrated controller is responsible for monitoring the operation of the DC screen, that is, it has to know every link of the operation of the DC screen as well. And make the system run in the best state. The battery patrol unit controlled by the system can provide voltage monitoring for each battery in order to detect the deterioration of the battery in the system as soon as possible, and replace the battery as soon as possible, so as to avoid the disastrous consequences of the system failing to provide DC power in time when the battery is out of power.

Insulation monitoring system can protect DC screen from damage to its own equipment or external equipment due to peripheral or self-system grounding. Battery configuration and reasonable selection can ensure the normal operation of the system in the case of power failure, and avoid the damage of the DC screen itself, resulting in the interruption of power supply to the system.

Charger is usually selected by high-frequency switching power module. Its humanized design makes the system design simple and reliable, and its price is reasonable. Generally, the DC screens below 220V 65Ah are all FR22005-1 high-frequency switching power supply module for electric power, while the DC screens above 220V 65Ah mostly use Emerson's products.

The communication system can provide detailed operation of DC screen for upper computer and remote alarm function. It can also select micro-computer insulation monitoring unit to realize small current insulation monitoring of feeder branch according to user's requirement.

In a word, DC screen is an ideal DC power supply screen for storage battery. It has the characteristics of large energy, small volume, stable voltage and ultra-low internal resistance. It can withstand strong impact current, 10-15 years of super-long life, safe use, no corrosive gas, no need for special battery room auxiliary maintenance equipment, and can be installed in the same control room with other control equipment, which can save a lot of capital investment. It is mainly used in transformer substations, substations and power plants as DC control and protection power supply and operation power supply for electromagnetic operation agencies. Now, it is also widely used in communication departments, computer rooms, hospitals, mines, hotels, and high-rise buildings, which are reliable emergency power supply.