Skip Navigation

About terminal substations

A terminal substation is a facility that forms a strategic node point in an interconnected electricity transmission system.

Major transmission lines from power stations south of Perth to the Perth metropolitan area carry 330kV of electricity, while 132kV and 66kV lines service the urban/ city network.

Terminal substations form the interface between long distance, high voltage transmission system (330kV) and the lower voltage (132 and 66kV), metropolitan transmission system which distributes electricity to consumers.

A terminal substation fulfils two primary roles:

  • It provides a connection point where transmission lines of the same voltage may be joined to enable an electricity supply to be established to a new demand centre, or to achieve a greater degree of interconnection within the existing system.
  • It is a transformation point where lower voltages are produced to supply the metropolitan transmission system.

Whilst the substations could theoretically be located at any point between the power station and the consumer, the efficient operation of the power system dictates that they are generally installed close to, or within, a demand centre.

The greater the distance between substations and demand centres, the greater the energy loss in supplying energy to customers.

New substations are often built by developing a 'break' in an existing line and closing the break at the substation.

Nearby lines of the required voltage may be redirected to the substation to improve security, or new lines established from the substation to meet consumer demand.

Cannington Terminal substation is a bulk supply point in the electricity network. It serves a significant area within the metropolitan area and some country areas.

Related Links

Page update on 25 October 2006