What is an Electric Screen?

Power distribution screens are power distribution equipment used to receive and distribute electrical energy and to control, protect and measure power distribution lines. Common distribution screens are divided into DC and AC.

The technical requirements and installation requirements for the power distribution screen are as follows.

(1) The left door panel in the power distribution screen should have the system diagram of this screen, the instrument wiring diagram, the control circuit wiring diagram and the corresponding terminal number diagram; the right door panel in the power distribution screen should have the electrical components installed in this screen. The table should indicate the manufacturer, model, and specifications.

(2) Each electric appliance, instrument, terminal block, etc. of the power distribution screen shall be marked with the number, name, road type (or use) and operating position.

(3) For the current circuit wiring of the secondary circuit in the power distribution panel, copper-core insulated wires with a cross-section of not less than 2.5mm² and a voltage of not less than 500V, and other circuit wiring cross-sections of not less than 1.5mm². Wiring should be neat and beautiful, well insulated, no joints.

(4) The low-voltage electrical appliances installed in the power distribution panel should be arranged neatly and in the same phase sequence.

(5) The control switch should be installed vertically. The upper end is connected to the power supply and the lower end is connected to the load. The center of the switch's operating handle is generally 1.2 to 1.5m from the ground; the side operating handle should not be less than 0.2m from buildings or other equipment.

(6) The switches controlling the two independent power sources shall be equipped with reliable mechanical and electrical locking devices.

(7) The power distribution screen should be firmly installed on the base steel. The top of the profile should be 10mm above the ground. The connection between the device inside the screen and each component should be firm.

(8) In rural areas where the electricity load is not large, you can make low-voltage power distribution screens yourself. Generally, a dry wooden board with a thickness of about 20mm is used, or a wooden sheet is covered with an iron sheet. The installation of various electrical appliances and meters on the screen should follow the principle of easy observation, operation and maintenance, and there should be measures to prevent electric shock on the exposed conductors on the panel. ^[1]

The design of the power distribution screen is generally performed according to the following steps:

1. Determine the control and protection scheme of the power distribution screen outlet

First of all, we must find out the power consumption in this power distribution area. According to the load distribution and the recent development plan, determine the three-phase three-wire or three-phase four-wire power supply methods.

After each line is determined, the control and protection scheme of each line can be determined according to the load of each line, the length of the line, and the requirements for power supply reliability, etc. Road, generally equipped with shunt isolation switch and shunt automatic switch; shunts with shorter lines and less load can be used

The screen of the power distribution screen: The screen of the power distribution screen should be smooth and painted, and the frame should be firm. The equipment on the screen should be arranged reasonably, and the wiring should be neat and beautiful. Meters and indicators should be installed in the upper part of the switchboard to facilitate monitoring and avoid damage; switches should be set in the middle for easy operation; heavier electrical equipment is set in the lower part to stabilize the switchboard; other devices are placed in short wiring. The bare aluminum bus bar fixed on the top of the power distribution screen should be painted with yellow, green, red, and black colors as phase separation signs. The distance between each device should meet the safety requirements.

Conductor:

1. Irrelevant personnel must not enter the power distribution screen room, and no other items can be stored in the room.

2. Operators of power distribution screens must understand and master power distribution management, safe operation knowledge, and maintenance techniques.

3 Wipe the power distribution screen often and keep it clean.

4 Fire protection equipment should be provided near the power distribution screen and the power distribution box, and they should be maintained to prevent failure.

5. Insulation rubber boards should be laid around the power distribution screen, and grid doors should be installed in the power distribution screen.

6. During the inspection, especially during the maintenance, a sign saying "Inspecting and Do Not Close" should be provided to prevent accidents.

7. The components of the power distribution screen must not be dismantled at will. To change the line, the approval of the person in charge of the equipment group must be obtained. ^[4]