Products
Transformer substations
Medium voltage switchgear, a transformer and low voltage distribution, supplied together as one station and set on site as a single item.
- Transformer
- rating and voltage pairsets the rest of the station
- Medium voltage side
- ring main unit or panelsset by the network connection
- Low voltage side
- incomer and outgoing waysset by the loads
- Enclosure
- operated from outside or walk inset by site and operating practice
- Standard
- IEC 62271-202AC prefabricated substations up to 52 kV
A transformer substation joins the medium voltage switchgear, the transformer and the low voltage board. Ordering it complete moves the integration risk to the manufacturer. A prefabricated station is type tested with its equipment inside, so its internal arc behaviour and temperature rise are proven for the whole assembly.
Your site and operating practice decide the type. A compact station keeps the footprint small and is operated from outside. A walk in station has an internal aisle. A package substation close couples the equipment on a common base, with no building around it.
Substation types
Stations in the UK
ENA EREC S40, Issue 2 of September 2026, is the UK engineering recommendation for prefabricated substations, with switchgear up to 36 kV and transformers up to 2000 kVA. For a station belonging to a distributor or generator, regulation 11 of the ESQCR requires live equipment in the open air to be fenced or walled against danger and unauthorised access. It also requires a notice with the owner and a constantly attended telephone number, and reasonable precautions against fire. Where a network operator will adopt the station, an ICP accredited under NERS builds it with equipment the operator has approved.
Transformer substation types compared
| Type | What defines it | Trade off |
|---|---|---|
| Compact substation | A prefabricated enclosure, type tested with its contents | Small footprint, operated through external doors |
| Walk in substation | A prefabricated enclosure with an internal operating aisle | More floor area, easier operation in poor weather |
| Package substation | Switchgear, transformer and low voltage cabinet close coupled on a common base | No building, quick to install, exposed to the weather through its own enclosures |
| Building integrated | Equipment installed in a room within a building | No external footprint, the room becomes part of the design |
Documents a station arrives with
| Document | What it shows |
|---|---|
| Single line diagram and general arrangement | The equipment inside, its ratings and where each item sits |
| Foundation and cable entry drawing | The plinth, the ducts and the earthing points the site prepares |
| Type test reports | The station or each item, as tested, including internal arc where it is claimed |
| Routine test reports | The tests on the transformer, the switchgear and the low voltage board before dispatch |
| Operating and maintenance manual | Switching, interlocks and the maintenance of each item |
Before the station arrives
A station is lifted from the vehicle onto its foundation in one operation, so the site work comes first. That means the plinth or pit, the cable ducts in the positions the drawing shows, the earth electrode and a hard standing for the crane. A delivery date only holds when all four are ready.
What every substation request needs
- Transformer rating and the primary and secondary voltage
- Medium voltage configuration: ring main unit functions or panel schedule
- Low voltage distribution: incomer rating, number and size of outgoing ways
- Enclosure type and whether it is operated from outside or from an internal aisle
- Site access for delivery and lifting, and the foundation arrangement
- Metering position and any network operator requirement
- Quantity, destination, required delivery date and acceptable condition
Specification template
Fill it in on screen or by hand, then upload it with your request.