Infrastructure

Dried out core and coil assembly is tightened before application of hot oil shrinkaging for 24 hours. The oil shrinkaging process avoids looseness of active parts during its service at site.

At last uniform pressing is done on Core and Coil Assembly. High mechanical rigidity is achieved by hydraulic pressing at circulated force and tightening all pressure screws. Pressed Core & Coil Assembly is put in to the tank with proper locating & locking arrangements which is of prime importance to achieve high resistivity against transient damages, vibrations during service and forces developing during fault occurrence.

After completion of Core & Coil Assembly insertion in tank, hot, degassed oil is then allowed into the transformed tank under vacuum. This oil is then circulated through the transformer and the oil degassing plant until all gas trapped in the core, windings, and the insulation is removed. This ensures a high degree of stability in the insulation structure and early attainment of its mature condition, which would not otherwise be achieved until the transformer had been in service for some time.

The transformer is made ready for testing after assembly of bushings, conservators, radiators and all other protective devices. All the joints are gasketed to avoid leakage with the help of rubberized cork sheets / Nitrite Rubberized O-Ring, which can withstand high oil temperature and do not deteriorate nor contaminate oil in its contact.