Distribution transformers are classified into oil-immersed transformers and dry-type transformers according to different insulation media, and into no-load regulating transformers and on-load regulating transformers according to different voltage regulation methods.
Under normal conditions, power distribution transformer should be installed on columns or outdoors on the ground. For the power distribution transformer in factories, workshops or suburban residential areas, they can be installed indoors according to specific conditions.
Column-mounted:
Single pole: The transformer, high-voltage dropout fuse and high-voltage lightning arrester are installed on the same pole, with simple structure, convenient installation, less material usage and small footprint, suitable for installation of power distribution transformer below 50KVA.
Double poles: Consisting of a high-voltage line terminal pole and another secondary pole (about 7.5m long), it is more sturdy than single pole and can install power distribution transformer of 63-315KVA.
Outdoor-ground-mounted transformers are placed directly on a platform (pedestal) made of bricks with a height of not less than 2.5m. It is convenient to remove and install transformers, and the capacity of transformers is not limited.
The distance between the transformer base and the ground should not be less than 2.5m, and all iron parts should be grounded.
The height of the exposed conductive parts from the ground should be above 3.5m.
The transformer base should be fixed with the rack, and the upper part of the power distribution transformer should be fixed to the pole with metal fittings.
Both upper and lower leads of the transformer should use multi-strand insulated wires. The distance from the ground to the high-voltage dropout fuse should not be less than 4m. The distance between the middle phase and the edge phase of the high-voltage fuse should not be less than 0.5m. The angle between the centerline of the porcelain part of the high-voltage fuse and the perpendicular line should be 250°-300°.
"Prohibition of climbing, danger of high voltage!" warning signs should be hung up.
The foundation of ground-mounted transformers should be 0.2m higher than the ground. In waterlogged areas, the transformer should be set up around the drainage ditch;
A brick wall should be built around the transformer, and the height of the wall should not be less than 1.8m. The door of the wall should be made of fire-resistant materials, designed on the low-voltage side of the transformer, open outward, equipped with locks, and bamboo or wooden fences should not be used.
The height of the transformer mount (pedestal) should not be less than 2.5m.
For two or more transformers installed outdoors, the distance between their enclosures should not be less than 1.25m.
The enclosure of the power distribution transformer should be properly maintained.
The distance between the transformer and combustible buildings should not be less than 5m, and the distance between the transformer and fire-resistant buildings should not be less than 3m.
"Stop, danger of high voltage!" warning signs should be hung up on walls or mounts (pedestals).
There should be good natural ventilation in the room.
The fire resistance rating of the transformer room should be level one.
The distance between the external casing of the transformer and the rear wall, the side wall should not be less than 0.6m, and the distance from the door should not be less than 0.8m. The doors and windows of the power distribution transformer room should open outward, and there should be louvers under them.
