In an electric power system, switchgear is the mixture of electrical disconnects fuses, switches or circuit breakers used for controlling, protecting and isolating electrical tools. Switchgears are used both for de-energizing equipment to let the work to be done and to clear off the faults downstream. This kind of equipment is directly connected to the dependability of the electricity supply.
Usually, switchgears in substations are situated on both the low-voltage and high-voltage side of large power transformers. The switchgear present on the low voltage side of the transformers may perhaps be situated in a building, with intermediate voltage circuit breakers for the distribution circuits, alongside with metering, protection and control equipment. For industrial applications, a switchgear and transformer line-up may possibly be united in one housing known as USS or unitized substation.
Switchgears are as aged as electricity generation. The initial models were very ancient: all constituents were merely fixed to a wall.