In
essence, the work of a substation is to operate as a switching, protection and
control equipment, and as transformers. There may be circuit-breakers (usually
in larger substations) that are used to interrupt any short-circuits or
overload currents that can occur in a network.
In
smaller substations, they use circuit breakers or fuses for the protection the
distribution circuits.
When
the central station grew larger, the smaller plants were converted into
distribution stations, receiving the power from larger plants rather than their
own.
A
compact substation is usually an outdoor substation built in a metal enclosure.
The items of the electrical equipment are located very near to each other to
create a relatively smaller footprint size of the substation.
Transmission station
These
smaller stations have different uses and functions to service the whole grid. The
first is the transmission station. It connects tow (or more) transmission
lines. One type has the same voltage. They may also have transformers to
convert two transmission voltages.
The
simpler ones can be as small as a truck while the biggest can cover several
hectares with multiple voltage levels, circuit breakers and many protective and
control equipments.
Distribution station
The
distribution station transfers power from the transmission system to the
distribution system in an area. It is used because it is not economical to
directly connect consumers to the main transmission network unless they are
using large amount of energy.
The
distribution voltages are typically medium (2.4 kV to 33kV). The feeders run
along streets overhead or via underground). The distribution transformers are
near the customer premises.
Added
to transforming voltages, the station also isolates faults in either the
transmission or distribution systems. They are typically the points of voltage
regulation. However, on long distribution circuits (long distances) voltage
regulation equipment may also be installed along the line.
In
addition to transforming voltage, distribution substations also isolate faults
in either the transmission or distribution systems. Distribution substations
are typically the points of voltage regulation, although on long distribution
circuits (of several miles/kilometers), voltage regulation equipment may also
be installed along the line.
Collector
In
distributed generation projects (wind farms) a collection substation Australia is needed.
It is like the distribution station, however, the power flow moves in the
opposite direction – from the many wind turbines to the transmission grid.
It is
also needed where multiple thermal or hydroelectric power plants are in
proximity. If there is no need for transformers for increasing the voltage, the
station becomes a switching station.
It
usually operates around 35 kV and the collector station steps up the voltage to
a transmission voltage for the grid. It can also provide power factor
correction if needed, metering and control of the wind farm. Sometimes, it can
contain HVDC converter station.
Converter
This
one is usually associated with HVDC converter plants, traction current or
interconnected non-synchronous networks. They have power electronic devices to
change the frequency of current.
Otherwise,
they convert from alternating to direct current or the reverse. These are some
of the substation Australia working types of in use today.
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