Oil-immersed transformer

powerimmersedfor industrial applications

The transformers are built in compliance with IEC 60076 (or other on request). For European market ,the calculation is made according to Ecodesign regulation, norms EN 50588-1. The core is made of high permeability crystal oriented steel sheet low loss, in a step section with 45° joints step-lap assembly, and is fitted with cooling channels. The winding conductors are all made of E-CU 99,9% electrolytic copper. According to the design of the transformer, windings can be continuous or interleaved disc, simple or multiple helix. Cooling channels are made with duly shaped rods and flow guide rings. Tappings are provided on the HV windings, controlled either by means of an off circuit switch or an on load tap changer. The windings are dried in autoclave in order to reach exact dimensions and avoid successive inelastic failure. The complete transformer is closed in the tank and filled with oil in vacuum conditions. The tank is normally of the vacuum type. Cooling is made by means of tank mounted radiators: mainly used are the bolt on, detachable type; some times welded solution is used. The units can be fitted with fans or pumps to increase the rating of the transformer. The transformers are capable of operation at output in excess of nominal rating in accordance with IEC 354. When dimensional considerations do not permit unit to be dispatched with insulating liquid, arrangements are made for filling the transformer tank with inert gas, or the dispatching of radiators and conservator detached.