Amorphous Alloy Dry-Type Transformer

It saves in no-load. No-load loss at 630 kVA is 410 W, while a cast resin silicon-steel unit of the same rating starts at 1340 W for SC(ZB)10 and is still above 750 W at its best band. Load loss is essentially the same, only slightly higher in the 2500 kVA band (18450 W against 17170 W). The annual saving is the no-load difference times the annual energised hours, independent of load factor. Send the annual energised hours and the tariff and both the figure and the payback can be calculated.

At indoor distribution points energised for long hours at a low average load factor — zoned distribution in a commercial complex, the mains side of offices and equipment rooms, municipal pumping stations, and redundant transformers on long hot standby. Hot standby is the clearest case: a standby transformer is energised year-round while carrying almost no load, so nearly all of its annual energy is no-load loss. On an industrial main transformer running at seventy or eighty per cent all year, load loss dominates and the relative gain is diluted; there the comparison worth making is against the later loss generations of the cast resin series.

No. In this series Yyn0 is available only at 400 kVA and below, while Dyn11 covers the whole capacity range. Where a project calls for Yyn0 above 630 kVA, the choice moves to the cast resin silicon-steel series or the vector group requirement is reconfirmed. This belongs in the first step of selection rather than the ordering detail — neutral earthing arrangement, unbalanced-load capability and protection configuration are all settled together with the vector group.

The interfaces line up; the dimensions may not. The windings are still epoxy-cast with a foil low-voltage side and the external interfaces follow the standard, but the section geometry of a wound core differs from a stacked one, so weight, overall dimensions and mounting dimensions are a separate set of figures and cannot be taken from a cast resin silicon-steel table of the same rating. Before an in-place replacement, measure the wheel gauge and the ground outline of the old foundation, then check them against the actual dimensions and load-bearing figures of the type selected.

The boundary is at 630 kVA. Crossing it changes the basis for calculating the prospective short-circuit current on the low-voltage side, so the breaking capacity of the switchgear below has to be recalculated against the actual band. Higher impedance means lower short-circuit current and less pressure on the switchgear, at the price of poorer voltage regulation. When weighing 500 kVA against 630 kVA, read this alongside the low-voltage switchgear ratings.

Yes. No oil pit is provided inside a module, which matches a dry-type unit naturally; where it travels with the module, the prefabricated power module line takes on the enclosure, the internal arrangement and the foundation fixing, and the transformer leaves the works as equipment inside it. The weight and overall dimensions of an amorphous unit differ from a cast resin silicon-steel one of the same rating, so the internal arrangement is set out from the actual data. Entry and exit directions, ventilation and cooling, and maintenance aisles are settled in one pass at the layout drawing stage.