Switchgear
One of the basic functions of switchgear is protection,
which is interruption of short-circuit and overload
fault currents while maintaining service to unaffected
circuits. Switchgear also provides isolation of circuits
from power supplies. Switchgear is also used to enhance system availability by allowing more than one
source to feed a load. Typically, switchgear in substations are located on both the high- and low-voltage
sides of large power transformers. The switchgear on
the low-voltage side of the transformers may be located in a building, with medium-voltage circuit breakers
for distribution circuits, along with metering, control,
and protection equipment. For industrial applications, a
transformer and switchgear line-up may be combined
in one housing.