1. WHY A DRY-TYPE DESIGN
A dry-type transformer is the choice when the equipment has to live close to people. Because the coils are encapsulated in epoxy resin, the SC(B)9/10/11/12/13 line is non-flammable, fireproof, explosion-proof, maintenance-free and pollution-free, and its compact size lets it be installed directly within the load centre. There is no oil to test, no tank to contain and no bund to build, so the site work and the running maintenance both shrink. Where the environment - a hospital, a data centre, a metro station, an industrial building - will not accept an oil-filled unit, the dry-type design removes the objection.
2. THE CAST-RESIN BUILD
The build is what separates a cast-resin transformer from an open, ventilated one. On the 35 kV line the high-voltage winding is filled with epoxy resin under vacuum casting, and the core uses a step-lap joint structure with the limbs bound in Class F single-sided non-woven glass tape and the core surface encapsulated in epoxy resin. The result is low partial discharge, low noise and excellent heat dissipation. The same casting principle - vacuum casting, a Class F resin system and self-extinguishing behaviour under flame - is set out at dry type cast resin transformer.3. RATING, VOLTAGE AND OVERLOAD
The SC(B) series is a 35 kV primary design stepping down to 0.4 kV for the low-voltage board. Rating, impedance, vector group and tap range are matched to the project specification before quotation, so the unit ordered matches the drawings approved for the site. Under air cooling the transformer is capable of continuous operation at 140% of its rated load, and it carries an intelligent temperature controller with fault alarms, over-temperature alarms and over-temperature tripping. The controller turns the thermal limits from a design assumption into a live protection.
