GSU transformers.
Generator step-up transformers take a plant's output from generator voltage up to transmission voltage. Each one is sized to the generator it serves.
RoleSteps generator voltage up to the grid
SizingMatched to the generator's MVA rating
Low sideGenerator voltage, often about 13.8 to 24 kV
Where they come fromRetired plants, canceled projects, repowering, spares
If you're selling, have ready
- Nameplate photo, with the maker and serial number
- MVA rating and the voltages on each side
- The generator it served, and its years in service
- Impedance, cooling class and vector group
- Factory test reports and the last field tests
- Oil test results and DGA history
- Tap changer type and tap range
- How it was stored after the plant shut down
- Removal: who, how fast, any site deadline
If you're buying, ask
- Whether the MVA rating and low side voltage match your generator
- Whether the high side voltage and impedance match your interconnection study
- The dissolved gas (DGA) trend, and any past faults or repairs
- Transport weight, and the route from its site to yours
- Which bushings, coolers and accessories are included
- How it was kept dry while idle
- Who pays for removal, shipping and testing on arrival
Why existing units matter
A GSU is built to order for one generator and one grid voltage, and a new one commonly takes two years or more to deliver.
A GSU from a retired plant, or a spare that was never installed, can serve a new generator when the ratings line up. We compare its nameplate and test records with your generator and interconnection data before anyone travels to see it. It still needs an independent inspection and a heavy haul plan.