Substations are locations where transmission lines, transformers, and generators are connected. They fulfill a number of functions:
- Allow power from different generating stations to be fed into the main transmission corridors.
- Provide a terminus for interconnections with other systems.
- Provide a location where transformers can be connected to feed power into the sub transmission or distribution systems.
- Allow transmission lines to be segmented to provide a degree of redundancy in the transmission paths.
- Provide a location where compensation devices such as shunt or series reactors or capacitors can be connected to the transmission system.
- Provide a location where transmission lines can be de-energized, either for maintenance or because of an electrical malfunction involving the line.
- Provide protection, control, and metering equipment/