Generator Step-Up (GSU) Transformers
Generator step-up transformers purpose-built for power plants — connecting generators to the transmission grid at elevated voltage. Optimised for continuous full-load operation with low losses, high reliability, and enhanced short-circuit withstand.
Engineering Features
Continuous Full-Load Rated
Designed for 100% continuous duty at nameplate rating — no derating required for base-load generator operation.
Technical Data
| Parameter | Range / Value |
|---|---|
| Rated Power | 10 – 200 MVA |
| Voltage Ratio | Up to 132 kV / 6.6–22 kV |
| Frequency | 50 / 60 Hz |
| Vector Group | YNd1 / YNd11 |
| Impedance | 12% – 18% |
| Cooling | ONAN / ONAF / OFAF |
| Tap Changer | OLTC ±10% / 17 steps |
| Temperature Rise | Top oil ≤ 55K, Winding ≤ 60K |
| Standards | IEC 60076 / IEEE C57.116 |
| Design Life | 40+ years |
Standard range parameters — custom specifications available on request.
Related glossary terms
IEEE C57.12
ANSI/IEEE distribution transformer standard
ANSI C57.12.00
General requirements liquid-immersed
DOE 2016
US Department of Energy efficiency rule
NEMA TR1
Sound level & loss tolerances
UL Listed
Underwriters Laboratories safety mark
IEEE C57.110
Harmonic-loaded transformer rating
Generator step-up (GSU) transformers for North American power generation. 10 MVA to 500 MVA up to 765 kV — IEEE C57.12.00 designed, KEMA short-circuit certified and seismic-qualified. Trusted by Independent Power Producers, IOUs and NRECA G&T co-operatives for thermal CCGT plants, gigawatt-scale solar and wind, hydro upgrades and gas-peaker fleets across ERCOT, PJM, MISO, CAISO and SPP territories.
ERCOT IPP Wind & Solar GSU · West Texas
PJM CCGT Power Plant GSU · Mid-Atlantic
MISO Wind-Farm Step-Up · Iowa, Minnesota, Dakotas
CAISO Solar GSU · Mojave & Imperial Valley
TVA Hydro Upgrade GSU · Tennessee Valley
Bonneville Power Hydro Step-Up · Pacific Northwest
Where Generator Step-Up (GSU) Transformers Excel.
Gas Turbine Power Plants
Step-up duty for simple-cycle and combined-cycle gas turbine generation.
Steam Turbine Generation
Coal, biomass, and nuclear steam-turbine generator interconnection.
Combined Cycle Plants
Optimised for CCGT auxiliaries and main generator step-up duty.
Co-Generation Facilities
Industrial CHP plants exporting surplus power to the utility grid.
Frequently Asked Questions
Deployed in
Related Knowledge
FAQs, glossary terms and sizing steps mapped to this product.
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