Large Power
Transformers

Yes. Copper is the standard specification for LIMIK power transformers, but aluminum conductors are available where your project calls for it. Conductor material — copper or aluminum — is set at the specification stage based on your loss targets, weight constraints, and budget.

A Power Transformer has fully separated primary and secondary windings and is used at utility substations to step transmission voltage down to distribution levels. An Autotransformer shares a portion of the winding between primary and secondary, which makes it more efficient for linking two transmission-level voltages — used at grid interconnection points, not at the customer end of the network. A GSU (Generator Step-Up) does the opposite job of a substation unit: it raises a generator's output voltage up to transmission level. Same engineering standards across all three — the difference is where each one sits in the power chain.

Yes. Impedance is a design target set at the specification stage, not a fixed catalog value. For a replacement transformer, matching the retiring unit's impedance is often necessary to avoid re-engineering the substation's protection and short-circuit coordination — our engineering team works from your existing system data to hit that target.

Yes. A three-winding transformer adds a tertiary winding, typically used to supply auxiliary station loads, provide a path for reactive power compensation, or interconnect a third voltage level at the same substation. Two-winding is the standard configuration; three-winding is specified when your substation design calls for that third connection point.

Every unit ships with a complete report covering the routine and type tests required under IEEE C57.12.90 — ratio, polarity, resistance, impedance and load loss, induced and applied potential, and excitation current among them. The report is provided before the unit leaves the factory, so your commissioning team has full data in hand before it arrives on site.

OLTC (on-load tap changer) adjusts voltage while the transformer stays energized and under load — standard on transmission-class units where continuous voltage regulation matters. DETC (de-energized tap changer) requires the unit to be taken offline to change taps — a simpler, lower-maintenance option suited to units where voltage conditions are stable and infrequent adjustment is acceptable. Your application and duty cycle determine which one fits.

The clock starts once your technical specification is finalized and the order is confirmed. Our engineering team works with you at the RFQ stage to resolve voltage class, impedance, cooling, and configuration before that clock starts — so the lead time you're quoted reflects your actual unit, not a placeholder spec.