The distribution transformer is installed outdoors, mainly on a special outdoor platform. The platform on which the transformer is installed is called a transformer platform, and there are two main types of transformer platforms: outdoor pole-mounted transformer platform and outdoor ground transformer platform.
The pole-mounted transformer should be installed close to the load center to reduce the line power loss and line voltage drop of the low-voltage power supply line. Generally, the transformer station is located near the unit that consumes more electricity, and at the same time, it should be ensured that the voltage drop of the furthest electrical equipment is within the allowable range. The installation location should be convenient for maintenance, and it should be avoided to install in complex poles such as corner poles and branch poles.
The distance between the transformer profile and the combustible building should be greater than 5m; the distance from the fire-resistant building should not be less than 3m. The distance between the transformer station and the ground should not be less than 2.5m; the lower edge of the low-voltage distribution box should not be less than 1m from the ground.
The height of all exposed charged objects on the transformer platform from the ground should be above 3.5m. Warning signs should be installed at obvious locations 2.5-3.0m above the ground.
When the high and low voltage lines are erected on the same pole, the low voltage lines should be located below the high voltage lines, and the distance between the high and low voltage cross arms shall not be less than 1. 20m.
In areas where the air contains flammable and explosive gases or dust that can damage insulation, pole-mounted transformer stations should not be installed, and indoor substations should be used.
When the outdoor transformer capacity is 320kVA and below, the pole-mounted transformer installation method can be adopted; when the capacity exceeds 320kVA, the ground transformer installation method can be adopted.
The floor-standing variable platform should have a solid foundation. The height of the foundation surface from the ground shall not be less than 0.3m. Generally 0.3 ~ 0.5m. During the safety period, a fence or fence with a height of not less than 1.8m should be set around the transformer. The net distance from the transformer shell to the fence or fence should not be less than 0.8m, and the net distance from the door should not be less than 2m.
The down-conductor pole of the platform should be in the fence. After the disconnector or fuse is cut off, the height of the live part from the ground should not be less than 4m, and should not be less than 3.5m when there is a barrier. The door of the transformer station should be locked, and the warning sign "Stop, high voltage danger!" should be hung on the door. Only after the power is cut off can you enter the fence.
The height of the cross arm of the drop-out fuse from the ground should not be less than 4.5m. The installation inclination angle of the transformer high-voltage drop-out fuse is 25°～30°, and the distance between phases should not be less than 0.7m.
The transformer on the pole should be installed smoothly and firmly. The waist fence is made of 4mm diameter cold steel wire (commonly known as iron wire) wound more than four times. The steel wire for cold pull should not have joints and the winding should be tight. The distance between the waist rail and the live part should not be less than 0.2m.
The installation of the fuse on the low-voltage side of the transformer should meet the following conditions; when there is an isolating switch on the low-voltage side, the fuse should be installed between the isolating switch and the low-voltage insulator; when there is no isolating switch on the low-voltage side, the fuse should be installed on the outside of the low-voltage insulator and insulated The wires are connected across the insulated wires at both ends of the fuse block.