There are several types of electrical substations, including but not limited to:
Distribution substation - used to distribute electricity from a high voltage transmission system to a lower voltage distribution system for distribution to end-users.
Transmission substation - used to connect different transmission lines and to step up or step down the voltage levels.
Converter substation - used in HVDC (High Voltage Direct Current) systems to convert AC to DC and vice versa.
Generator substation - used to connect a power generating source, such as a hydroelectric, nuclear or thermal power plant to the transmission system.
Load-break substation - used to disconnect a section of the transmission or distribution system to allow maintenance or repairs to be done safely.
Recloser substation - used to automatically detect and isolate a fault on a distribution line, allowing the rest of the system to continue operating.
Switching substation - used to switch power flows between different transmission lines, or to connect or disconnect transmission lines from the rest of the system.
Regulating substation - used to control the voltage levels of the transmission or distribution system by adjusting the amount of power flowing through a particular line.