Electrical transformers for the distribution of electrical power in urban areas.

This transformers are built according to IRAM 2250 and IEC 76 regulations.
Urban transformers can be built in three different ways:

a. With an expansion tank. Type I.
b. Without an expansion tank. Hermetically sealed, with expansion chamber.
c. Without expansion tank. Hermetically sealed, oil filled.



Transformers of type “c” are completely filled with isolating oil. Energized parts are never in contact with the atmosphere, hence preventing both humidity from reaching them, and the fluid to come into contact with oxygen. These measures prevent the unit’s decay due to rust, and it increases the lifespan of both the isolating oil and the transformer, with proper maintenance.

With a very reduced size, it’s specially designed case comes with fenders, reduces the volume differences that could be caused by temperature changes.

d. Submersible hermetically sealed pit transformers: they are impregnated with mineral oil and can be submerged underwater. They are more commonly used underground, in places where flooding is a possibility, both because of the rain or the rise of groundwater levels. It’s external paint is zinc rich and has an epoxy layer, with epoxy bituminose finishing. It’s unique design comes with some special accessories, besides those common to all transformers:

· Mid-Tension connectors can be operated while charged, with pole – elastimold type.
· Low-Tension plugs – Copper connectors electrically isolated with epoxy.
· Pods and fuses that can be operated externally.
· Internal pressure gauge.
· Pneumatic valve for the ejection and injection of nitrogen.
· Pressure relief valve.

Subtransmition and mid power up to 10 MVAs.s