DISTRIBUTION TRANSFORMERS
Distribution Transformers

On the last transformation step from the power station to the consumer, distribution transformers provide the necessary power for systems and buildings. Power range is from 25 kVA to 4000 kVA with 36kV voltage level. Accordingly, their operation must be reliable, efficient and, at the same time, silent. Distribution transformers are used to convert electrical energy of higher voltage, usually up to 36 kV, to a low voltage, with an identical frequency before and after the transformation. Application of the product is mainly within suburban areas, public supply authorities and industrial customers. They are usually the last item in the chain of electrical energy supply to households and industrial enterprises. Distribution transformers are fail-safe, economical and have a long life expectancy.

 

Oil immersed:

These oil immersed transformers can be 1-phase or 3-phase. During operation, the windings can be exposed to high electrical stress by external overloads and high mechanical stress by short-circuits. They are made of copper or aluminum. Low-voltage windings are made of strip or flat wire, and the high-voltage windings are manufactured from round wire or flat wire.

 

There are two types, hermetically sealed and with expansion tank. Hermetical type distribution transformers are produced as contactless to atmosphere by adjusting the pressure at factory environment. It can be designed to resist the effects of changing oil pressure as a result of heat by expansion and contraction of corrugated wall. Since it has no expansion tank, oil process is conducted at special vacuuming rooms. With oil filling process that conducted under vacuum, the lifespan of transformer increases. Heights of hermetical transformers are smaller than expansion tank type transformers. As a result of this reason hermetical type transformers can fit much smaller spaces. Since the oil is contactless with atmosphere there won’t be a need for oil change periodically. No maintenance necessary other than cleaning of the HV and LV bushings.

 

Oil expansion tank type distribution transformers are produced with 3 or 1 phase levels, oily, natural cooling systemic ( ONAN), idle-load tap changer or under-load automatic tap changer. Expansion tank type transformers are identical with hermetical type transformers in terms of their core and coil structure. The dimensions of expansion tanks are designed by calculating the expansion levels, of heated oil. Since the expansion tank type transformers are open to atmosphere, air intake provided by the silica gel which is ate the tank of the transformer. This silica gel and the oil should be changed periodically because silica gel lost its feature as a result of air exchange.

 

Dry type transformers:

We offer cast resin dry type distribution transformers with the power levels between 25 kVA and 3000 kVA with the voltage levels of 36 kV. The HV and LV windings are covered by epoxide resin under vacuum and natural air cooling (AN) or fan cooling (AF) options also available. By using fan cooling 50% of extra power increase can be maintained.

 

The epoxide resin that poured under vacuum prevents the humid from entering the transformer and provides protection against challenging environments. There is no risk of fire and pollution because of the non-burnable feature of epoxide resin. Cast resin dry type transformers’ dimensions are smaller than oil type transformers so they need much smaller spaces. Their lifespan is longer than oil type transformers. They are more useful because of their high resistant features against short circuits. No maintenance necessary.

 

Our Brands:

We offer ABB, Siemens and Best distribution transformers, dry and oil type.