Delivered projects

Tenaska Fluvanna: control cabinet delivered for a 495 MVA, 525 kV GSU transformer

The control cabinet for the 495 MVA, 525 kV GSU (generator step-up) transformer that Siemens Energy is building for Tenaska’s steam turbine in Fluvanna, Virginia (U.S.), has left our factory: the transformer’s cooling, protection, and alarms, all in one cabinet.

By Thiago Coracini
October 24, 2026
2 min read

Assembled control cabinet on the factory floor with both outer doors open, lined with foil-faced thermal insulation, and the white inner doors closed and lit from inside

Our latest delivery left the Alltec factory on October 19: the control cabinet for the 495 MVA, 525 kV GSU (generator step-up) transformer that Siemens Energy is building for Tenaska.

Where it will operate

Its destination is the Fluvanna substation in Scottsville, central Virginia (U.S.). There, the transformer takes the output of a steam turbine generator and steps it up to the 525 kV transmission grid. All of the turbine’s output flows through it, which is why cooling, protection, and alarms are brought together in a single cabinet.

Built for the outdoors

The cabinet works next to the transformer, out in the open. It is outdoor-rated, painted to withstand the weather in the same color as the transformer tank, with thermal insulation on the walls and doors and heaters that keep condensation from forming inside.

Closed light-gray cabinet on a wooden skid on the factory floor, with two doors, a rectangular viewing window in the right door, black handles, and a lifting eye on the roof — The closed cabinet, ready to ship, with the viewing window in the door for reading the alarms

Another one for Tenaska

This is the fourth control cabinet for transformers at Tenaska power plants that Alltec has delivered since 2024, all for Siemens Energy — and two more are already underway. A partnership of 25 years, project after project.

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