Prefabricated Substation Buying Guide | Layout, Rating and Site Work
1. Confirm the transformer rating and the MV scheme
Start from the load and the transformer capacity, then fix the MV switching arrangement: ring main unit, load break switch or circuit breaker, and how many transformer feeders. The transformer rating sets the room size, the LV busbar and the ventilation, so it must be settled before the enclosure layout is drawn.
2. Choose European, American or compact design
| Design | Layout | Typical use |
|---|---|---|
| European style (YB series) | Separate MV, transformer and LV rooms in one enclosure | Utilities, industrial parks, public distribution |
| American style (ZGS) | Compact, transformer and switchgear in one tank or enclosure | Small sites, overhead or cable-fed distribution |
| Compact intelligent (YBM) | Integrated RMU, transformer and LV with SCADA | Data centres, rail, smart grids, unmanned sites |
European designs give clear room separation and easier maintenance. American designs are smaller and cheaper for simple sites. Intelligent designs add remote monitoring and control but need a communication and power supply plan.
3. Plan the room layout and cable entry
Confirm the cable entry direction, the trench and pad dimensions, the working clearance in front of the switchgear and the door opening space. Transformers need lifting access and, for oil-immersed units, an oil containment arrangement where required. Check that the LV cable exit does not cross the MV compartment.
4. Check the enclosure, ventilation and corrosion class
The enclosure must handle the site ambient, solar gain and the transformer heat loss. Confirm the IP rating, the ventilation louvres, the insulation and the corrosion class for coastal or industrial air. A sealed enclosure without adequate ventilation overheats the transformer and derates its output.
5. Agree transport, foundation and commissioning
Check the transport dimensions and mass against the route, and confirm the lifting points and the shipping split. The foundation must be level and set to the drawing before the unit arrives. On site, the package needs cable termination, earthing, protection setting and a commissioning test before energisation.
6. RFQ checklist
- Transformer rating, voltage ratio and vector group
- MV switching arrangement and protection
- LV feeders, busbar current and metering
- European, American or compact intelligent design
- Enclosure IP rating, ventilation and corrosion class
- Transport, foundation and lifting constraints
- Quantity, destination and delivery date
Send the load data and the site plan and the substation layout can be confirmed in one round.
