Substations
Package substations
A ring main unit, a transformer and a low voltage cabinet close coupled on a common base, installed outdoors without a separate building.
- Arrangement
- close coupled on a common baseno connecting cables between units
- Placement
- outdoors on a plintheach unit carries its own weather protection
- Medium voltage
- ring main unitconfiguration set by the network
- Transformer
- liquid immersed, commonly
- Low voltage
- cabinet with incomer and outgoing waysset by the loads
A package substation joins the ring main unit, the transformer and the low voltage cabinet directly to one another on a common base. Close coupling removes the interconnecting cables and the building from the site works. What remains is the foundation, the incoming and outgoing cables and the earthing.
With no building, each unit relies on its own enclosure for weather protection, and the arrangement is more exposed than a prefabricated station. Where security, appearance or climate call for an enclosure, a compact substation or a separate housing is the usual alternative.
In Great Britain, a package substation owned by a distributor or generator falls under regulation 11 of the ESQCR. Live equipment in the open air is fenced or walled to at least 2.4 m, and the station carries safety signs and a notice naming its location, its owner or operator and a constantly attended telephone number.
What gets specified
| Parameter | Typical options | What decides it |
|---|---|---|
| Ring main unit | Configuration and insulation medium | The network, and the rules on fluorinated gas at the destination |
| Transformer | Liquid immersed in most packages, flanged to the units either side | The load, and the flange arrangement of the switchgear chosen |
| Low voltage cabinet | Incomer and fused outgoing ways | The circuits the site needs |
| Base and coupling | Common skid or plinth, flange coupling between units | The manufacturer's arrangement |
| Weather protection | The IP rating of each unit's own enclosure | Exposure at the installed position |
| Surround | None, or a fence or housing | Security, appearance and climate |
Applicable standards
| Standard | What it covers |
|---|---|
| IEC 62271-200 | The ring main unit at one end of the package |
| IEC 60076-1 | The transformer in the middle |
| IEC 61439-1 and IEC 61439-2 | The low voltage cabinet at the other end |
| IEC 60529 | The IP code each unit's own enclosure is rated to |
What a package substation request needs
- The ring main unit configuration and its insulation medium
- The transformer rating and voltage pair
- The low voltage incomer and the number of fused ways
- Whether a surround or housing is wanted
- The plinth dimensions, where the plinth already exists
Specification template
Fill it in on screen or by hand, then upload it with your request.