Oil Type Distribution Transformers

Bushings

Bushings of the solid porcelain type comply with international standards and are generally located on the cover. Transformers can also be provided with plug-in bushings.

Core

The core is manufactured with first rate, grain oriented magnetic, cold-rolled silicon steel laminations. The mounted core is clamped down in order to reduce vibrations and minimize noise levels. Further noise level and no load losses decreasing are achieved by step lap core construction. The geometric core arrangement and the materials chosen determine the losses and noise levels. It is cut by the most modern, fully automated core cutting machinery and assembled into limb and yoke sets. This results in high dimensional accuracy, excellent space factor, and low loss values. By using step-lap technology, the no-load currents can be reduced improving the drawbacks associated with reactive power compensation.

Vacuum treatment

Drying and vacuum treatment is performed using proven technology such as vapor phase drying and LFH(low frequency heating) Before filling,the oil is always degassed and purified.

Additional accessories can be fitted according to customer's specifications.

oil level indicatorThermometer

Insulating oil

The mineral oil – both inhibited and uninhibited types – with its electrical and chemical characteristics is in compliance with the IEC Standards and is P.C.B. and P.C.T. free.

Tanks 

Tank walls are made of corrugated cooling surfaces. The bottom plate, side and frames are of welded construction. The welds are tested for oil tightness.

The complete tank is tested and approved according to CENELEC HD 428.6 S1(EN 50464-4) standard.

Special type lifecycle tests of more than 10 000 cycles simulating over 30 years operation were carried out with positive results.

Painting and surface treatment

All metal parts are carefully sand-blasted. The initial protective coating is made up of a single coat of one pack epoxy paint. The final paint coating is made up of several coats of paint.

Alternatively, hot dip galvanized transformers can be supplied for use in heavy corrosion areas. All units are painted in RAL 7035 but other colors are available on request. Detailed painting procedures for different environmental conditions are also available.