GSU generator step-up transformers for power plants up to 670 MVA, 400 kV
Generator Step-Up (GSU) transformers connect a power plant generator to the high-voltage grid. The largest unit built has 670 MVA at 400/22 kV. They are used at thermal, combined-cycle and hydroelectric plants and large renewable energy sites.
- Rating (built project)
- up to 670 MVA (the largest transformer made in Italy)
- Voltage
- up to 400 kV (example: 400/22 kV)
- Vector group
- YNd11 (example)
- Cooling
- ODAF (example)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Power generation sites are usually far from where the electricity is consumed. To transmit it economically over long distances, a step-up transformer converts the voltage and current at the generator output. It sits between the generator terminals and the high-voltage grid and takes the full output of the generating unit, so strict requirements apply to losses, short-circuit withstand and operating stability. The winding design and cooling system are calculated for the duty of a specific unit rather than taken from a standard range. For this reason the item is presented as a type of apparatus, while rating, voltage and vector group are fixed in the project.
The manufacturer designs such transformers individually, for the generator parameters, the power evacuation scheme and the site conditions. This applies to plants on both conventional and renewable sources. The standards are IEC, in the edition specified by the customer's technical requirements. For spare generator step-up transformers that may serve at different plants, the design is also made to order. Design, manufacture and testing take place in one location, which simplifies agreeing parameters with the customer. Testing is carried out on the manufacturer's own test benches to IEC standards.
The scale is illustrated by a project for Ansaldo Energia. Three transformers were built for the Tavazzano-Montanaso thermal power plant, including the largest ever made in Italy, 670 MVA, 400/22 kV, vector group YNd11, ODAF cooling, weight about 350 t. Design and manufacture were carried out at the Legnano plant, together with testing and delivery to the site.
The transformers are made with mineral oil or as green units with natural or synthetic ester, which reduces fire hazard and environmental risks at the plant. The manufacturer's research work is aimed at lowering losses and noise, analysing electrodynamic forces during short circuits and mechanical loads under seismic effects and transportation, as well as diagnostic systems and analysis of fast transient overvoltages. The manufacturer produces about 200 transformers a year. It also repairs, upgrades and leases transformers, but these services are not part of the item. Applications are thermal, combined-cycle and hydroelectric plants and large renewable energy sites.
Technical specifications
| Rating (built project) | up to 670 MVA (the largest transformer made in Italy) |
|---|---|
| Voltage | up to 400 kV (example: 400/22 kV) |
| Vector group | YNd11 (example) |
| Cooling | ODAF (example) |
| Weight | about 350 t (670 MVA example) |
| Insulating liquid | mineral oil or natural/synthetic ester |
| Generation sources | conventional and renewable |
| Standards | IEC (per customer's technical requirements) |
Replacement for
ТДЦ-125000/110, ТДЦ-250000/220, ТДЦ-400000/330, ТЦ-630000/500, ОРЦ-533000/500, ОРЦ-417000/750 (generator step-up)
selected by purpose and main parameters, please confirm with our manager
Request a price and lead time
GSU generator step-up transformers for power plants up to 670 MVA, 400 kV. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What rating and voltage do GSU generator step-up transformers have?
The largest unit built has 670 MVA and 400/22 kV, vector group YNd11, ODAF cooling. This transformer weighs about 350 t.
What insulating liquid is possible in GSU transformers?
Mineral oil or natural or synthetic ester. The ester version reduces fire hazard and environmental risks at the plant.
Which power plants are these transformers intended for?
For thermal, combined-cycle and hydroelectric plants, and for large renewable energy sites. The parameters are selected for the generator, the power evacuation scheme and the site conditions, with IEC standards.
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