Three-Phase Transformer
A transformer for three-phase power systems with three winding sets on a common core.
Designed for three-phase AC systems (standard worldwide). Types: single unit (three windings on three-limb core, up to ~200 MVA) or bank of single-phase transformers (for very large, transport limits, redundancy).
Connections: Yy, Yd, Dy, Dd, Z. Vector group (Dyn11, Yyn0) defines connection and displacement.
Three-phase units more economical (less steel, smaller footprint) but single failure requires full replacement.
QDTB manufactures three-phase transformers from 30 kVA to 500 MVA in all standard configurations with three and five-limb cores.
Related Terms
Vector Group
Standardized designation of transformer winding connections and phase displacement between HV and LV.
Transformer
A static device transferring energy between circuits through electromagnetic induction, changing voltage and current levels.
Power Transformer
A large transformer (>10 MVA) used in transmission networks for stepping voltage between system levels.
Distribution Transformer
A transformer stepping down voltage from the distribution network (11-33 kV) to utilization voltage (400/230V) for end consumers.
More Terms Starting with “T”
Transformer
A static device transferring energy between circuits through electromagnetic induction, changing voltage and current levels.
Tap Changer
A device adjusting transformer turns ratio by connecting to different tap points on a winding.
Temperature Rise
The temperature increase of transformer components above ambient at rated load, a key design parameter.
Turns Ratio
The ratio of primary to secondary winding turns directly determining voltage transformation ratio.
More in “Transformer Types”
Autotransformer
A transformer with a single winding acting as both primary and secondary, providing voltage conversion through electromagnetic induction and direct electrical connection.
Amorphous Alloy Transformer
A distribution transformer using amorphous metal core material achieving 60-70% lower no-load losses than conventional silicon steel cores.
Box-Type Substation (Prefabricated)
A factory-assembled compact substation integrating transformer, HV/LV switchgear, and protection in a weatherproof enclosure.
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