Considerations for siting an area substation

An area (distribution) substation steps down sub-transmission voltage (e.g. 66 or 33 kV) to primary distribution voltage (11 kV) and feeds a number of feeders. Its site is chosen considering:

1. Load centre: as near as possible to the centre of the present and future load, so 11 kV feeders are short, with low voltage drop and loss.
2. Supply source: close to the incoming sub-transmission line for short, cheap connection.
3. Feeder exits: enough space and routes for outgoing feeders in all directions.
4. Land: enough area for present needs and future expansion (more transformers and bays); reasonable cost; clear ownership.
5. Access: road access for heavy transformers and maintenance vehicles.
6. Site conditions: level, firm ground with good drainage; free from flooding, landslides and pollution; good soil resistivity for earthing.
7. Environment and safety: away from residential crowding, schools and hospitals; noise and visual impact acceptable; fire safety.
8. Communication and water facilities for operation.
9. Cost: total cost of land, site preparation, lines and losses should be minimum.
10. Regulations and public acceptance: comply with local by-laws and get community consent.