Substations may be classified as either transmission or distribution substations, depending on their voltage class and the purpose of the substation.
Transmission substations (TS) are the larger, higher-voltage substations, while distribution substations (DS) are the smaller, lower-voltage substations.
A typical transmission substation will have a voltage rating of 138 kV or above, while a typical distribution substation will have a voltage rating of less than 138 kV.
Substations may also be classified by their use. There are three main types of substations:
- transmission substations
- distribution substations
- switching substations