Kiosk transformer station: when you need one and what the design involves

27 October 2026 · 4 min read

Above a certain power a low-voltage connection is no longer enough and the grid operator requires a medium-voltage connection. Then you need your own transformer station – usually a kiosk one.

When a low-voltage connection is no longer enough

The low-voltage distribution grid (400 V) is designed for ordinary consumption. As soon as a project needs hundreds of kilowatts – whether it is battery storage, a larger solar plant, a production hall or a charging hub – the grid operator usually specifies in its statement on the connection application a connection at medium voltage (22 kV). That means your own consumer or generation transformer station: a 22/0.4 kV transformer, MV switchgear with the operator's panel and LV switchgear for your site.

The exact threshold is not fixed by power; the state of the grid at the location and the operator decide. In practice, an MV connection is expected from outputs in the order of hundreds of kW upwards.

Types of transformer stations

Type	When it suits
Kiosk (prefabricated concrete)	The most common choice: delivered as a finished unit, placed on a foundation or gravel bed, contains the MV switchgear, transformer and LV switchgear. Variants with internal or external operation.
Brick-built / built-in	Part of a building or site; makes sense where there is space inside and requirements on appearance.
Pole-mounted	For smaller outputs on an overhead MV line; cheap, but limited in power and operation.

For storage and solar plants the kiosk station prevails: quick installation, clearly defined spaces for the operator and for the investor, and well-handled requirements on earthing and fire safety.

What the grid operator requires

Each operator has connection conditions for stations owned by the applicant. They typically cover:

The operator's panel in the MV switchgear – arrangement of panels (incoming, outgoing, possibly a bus coupler) according to the power and number of transformers; the ownership boundary runs at the output of the operator's panel.
Metering – up to a certain power on the LV side, above it on the MV side with instrument transformers; the location and design of the metering is approved by the operator's metering department.
Access – the operator's switchgear must be accessible at any time from a publicly accessible place, including access for the metering vehicle; the operator therefore approves the station's location before it goes to the building authority.
Earthing – a ring earth electrode, a threshold electrode in front of the entrances, earthing resistance; where an electrode cannot be laid, an alternative in the cable trench.
Protection and dispatch – for generating plants, a disconnection point, grid protection and communication with the dispatch centre.

The conditions change; before the design we always work with the current wording of the connection conditions and submit the design to the operator for approval.

What the transformer station design includes

Study and choice of solution – station type, transformer rating, number of MV panels, position on the plot with regard to the operator's access, MV supply route, protection zones, indicative costs.
Connection application – site plan, diagram and data for the operator; the statement sets the point of connection and the conditions.
Permit documentation – site plan, plan and elevations of the station, technical report, fire safety solution, statements from utility operators and the concerned bodies.
Detailed design – station layout, MV and LV diagrams, metering, earthing and lightning protection, cable routes, short-circuit calculations and protection settings, external influences report, bill of quantities.
As-built documentation – after construction, for the inspection, the operator and the station's operating instructions.

We usually design the station together with what it supplies – the storage, the solar plant or the site – in one set of documentation, so that the ratings, protection and metering fit together. More on the transformer station design page.

What not to forget

Location next to a public space – the most frequent reason for redesign. When the station cannot stand at the boundary, an access path and an easement have to be arranged.
Transformer rating with a reserve – replacing a transformer is expensive; we choose the reserve with regard to the planned development of the site and the operator's conditions.
Noise and appearance – the transformer is a noise source; near housing it is assessed. Kiosks can be adapted in colour and surface finish.
Operation – a station with operating staff requires local operating instructions, inspections and a person responsible for the electrical equipment.

Frequently asked questions

Who owns the station?

A consumer or generation station is the investor's property; the operator owns and operates its panel in the MV switchgear and the metering. The ownership boundary is set by the connection conditions and the connection contract.

How long until the station is standing?

The delivery and installation of a kiosk station itself is a matter of weeks. The overall time, however, is not set by the installation but by waiting for the operator's statement and above all by the length of the permit procedure at the building authority, which nobody can guarantee in advance. It is counted in months, longer for more complex connections – which is why we prepare the application and the documentation as early as possible.

Can we share the station with another project?

Yes, if the transformer rating and the LV switchgear arrangement allow it. Storage, a solar plant and the site's consumption can all be connected through one station; the metering of the individual parts is then arranged.

Planning a similar project?

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