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
ENATS 35-1
DNO-approved distribution transformer specification
ENATS 35-2
UK secondary substation transformer standard
G99 Compliant
Engineering Recommendation G99 grid interface
BS EN 60076
British Standard for power transformers
KEMA Certified
Independent short-circuit witness testing
EcoDesign Tier 2
EU 548/2014 efficiency compliance
Generator step-up (GSU) transformers for UK power-generation projects. 10 MVA to 500 MVA up to 525 kV — BS EN 60076 type-tested with KEMA short-circuit certification, designed for continuous full-load operation, low losses and short-circuit withstand. Standard supplier for offshore-wind onshore substations, CCGT and OCGT plants, pumped-storage hydro and the UK's nuclear new-build programme.
Offshore Wind Onshore-Substation GSU · North Sea
UK CCGT Power Stations · Generation Step-Up
Pumped-Storage Hydro Plants · Scotland & Wales
Nuclear New-Build GSU · Hinkley Point C
Gas-Peaker & OCGT Plants · UK Capacity Market
Onshore-Wind Farm Step-Up · UK Renewable Sites
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
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Related Knowledge
FAQs, glossary terms and sizing steps mapped to this product.
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