Power Substation
A substation is a part of an electrical generation, transmission, and
distribution system. Substations transform voltage from high to low, or the
reverse, or perform any of several other important functions. Between the
generating station and consumer, electric power may flow through several
substations at different voltage levels. A substation may include transformers
to change voltage levels between high transmission voltages and lower
distribution voltages, or at the interconnection of two different transmission
voltages. They are a common component of the infrastructure. There are 55,000
substations in the United States.[2]
Substations may be owned and operated by an electrical utility, or may be owned
by a large industrial or commercial customer. Generally substations are
unattended, relying on SCADA for remote supervision and control.
The word substation comes from the days before the distribution system became a
grid. As central generation stations became larger, smaller generating plants
were converted to distribution stations, receiving their energy supply from a
larger plant instead of using their own generators. The first substations were
connected to only one power station, where the generators were housed, and were
subsidiaries of that power station.
Service Features
Substations contain the specialist equipment that allows the voltage of
electricity to be transformed (or 'switched'). The voltage is stepped up or
down through pieces of equipment called transformers, which sit within a
substation's site.
The primary function of a substation is to transform
the high voltage electricity produced by power plants into lower voltages
that are safe for distribution and use. The process begins at the power
plant, where electricity is generated at a relatively low voltage.
Switch transmission and distribution circuits into and out of the grid
system. Measure electric power qualities flowing in the circuits. Connect
communication signals to the circuits. Eliminate lightning and other
electrical surges from the system.