Thermal / campus GSU capability class - ~990 MVA · 345/24 kV

What capability class means

This listing is an RFQ shape drawn from published OEM capability patterns. It is not a named unit for sale, not inventory, and not a reserved factory slot. The reference exists so a buyer planning a very large generation block can start a structured quotation without inventing a spec sheet from scratch.

At this rating the practical questions shift from electrical parameters to feasibility: which factories can build and test the unit, what test-bay and short-circuit capability the FAT requires, and whether the site can even receive the tank.

Single-phase banks versus one three-phase tank

Near 1000 MVA, OEM education describes single-phase banks as a common alternative to a single three-phase tank. Three single-phase units plus a spare cut the transport envelope per piece and give the yard a spares story, in exchange for more pads, more bushings, and more yard bus. The choice belongs to the owner engineer and the study, and the RFQ should state which shape is wanted or ask each OEM to propose.

Haul and FAT dominate this class

DOE's 2024 Large Power Transformer Resilience Report describes LPT shipping weights of roughly 150 to 400 tons, and the largest GSU classes sit at the top of that band. Route surveys, bridge ratings, rail or Schnabel availability, and last-mile SPMT work should be scoped before the PO, not after FAT. GAO reporting in 2023 noted transport alone can run to hundreds of thousands of dollars for some moves.

FAT witness for a unit like this is usually in person for the key dielectric and loss tests. Write the witness rights, the test list per IEEE C57.12.90 or IEC 60076, and the shipping and impact-recorder requirements into the same contract section.

Two clocks on the listing

The catalog ARO band on this reference is a marketplace target subject to confirmation. Market survey clocks for the largest classes run much longer, and EHV or highly custom units have been framed at up to about five years in DOE-linked hydropower addendum reporting. Both clocks are labelled on the listing so planning can use them honestly.