Cooperative Living May 2015 - 25

IT'S YOUR BUSINESS by Karen Combs, Contributing Writer
How Transformers
Direct Traffic on the
Electric Highway
S
ending power to your home
is a lot like driving to a
neighboring state. You
wouldn't consider taking a twolane
secondary road to travel to
a city hundreds of miles away,
would you? Of course not: You
would find the nearest interstate so
you could drive faster and arrive
at your destination in less time.
Just like you, your electricity
has an interstate that allows it
to travel long distances, and a
secondary system that winds
through back roads and neighborhoods
to direct it to its final destination,
your home.
Transmission lines that deliver
power from a power plant to substations
are the fast-moving interstate
highways of the electric
industry. These lines carry up to 230,000 volts of electricity into
the local distribution substation. They are located on structures
ranging from large metal towers more than 100 feet tall to a
single pole standing 70 to 90 feet in the air.
And just like a car leaving the interstate, the electricity leaving
the substation has to slow down when it enters the distribution
lines serving your co-op's service area. Transformers in the
substation provide the braking system for lowering the voltage
of the electricity so it can continue safely along its journey.
So, how does it work? Higher-voltage electricity passes
through a system of coiled wires located in the substation transformer.
The electricity enters a primary side of the transformer,
which has metal coil windings surrounding that side of the transformer,
and then passes to a secondary side, which has fewer
coil windings. Travelling through the reduced number of windings
lowers the voltage as it leaves the secondary side and continues
the journey along the distribution lines.
The electricity moving along your co-op's distribution lines
is cruising between 7,200 and 12,470 volts, depending on
whether or not it's travelling along a single-phase, two-phase or
three-phase line. Consider these lines the secondary roads of
the electric system. They make the journey through your local
co-op's service area.
May 2015/www.co-opliving.com
Distribution lines carry the
electricity shorter distances than
transmission lines. They transport
electricity to the businesses,
schools and homes served by
your co-op. These are the lines
you typically see co-op line
crews repairing after a storm.
Your electricity has one more
stop before making its way into
your home. Just as you slow
down to pull into your final destination,
the voltage is lowered
one more time. It takes a turn off
the distribution line and into
another transformer that's located
outside your home.
This transformer may be a
canister hanging on a pole or a
box in your yard if you have
underground electric service.
Like the substation transformer, the electricity passes through a
primary side with more coil windings to a secondary side with
fewer coils. The voltage leaving the secondary side is generally
between 120 and 240 volts.
Most transformers serve
only one home or business,
but in some subdivisions two
homes may share a single
transformer. These transformers
are protected by fuses
that will disconnect them
from the electric line if there
is a fault caused by current
surges or overloads.
After the electric current
Transmission lines
that deliver power
from a power plant
to substations are the
fast-moving interstate
highways of the
electric industry.
leaves the transformer, it
makes its way through a service line, into the meter base and
to its final destination - your home - where it powers the
appliances and electronics of our modern world. As you can
see, the electric highway plays a key role in powering our lives
and delivering safe, reliable and affordable electricity to you. n
Source: NRECA, www.nreca.coop
23
GYN9038/ISTOCK/THINKSTOCK
http://www.nreca.coop
Cooperative Living May 2015

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