Transcript Electrical Power Generation

Electrical Power
Generation
What’s on the other end of a power line?
A Special Report by
Mr. Meador & Ms. Shaw,
Bartlesville High School
Tour Pictures from 1995
2008 Revision
www.bhsphysics.org
Darkness
Join us on a trip to a typical electric power plant, where we
hope to shed some light on the subject of electric power
generation.
To Oologah
Bartlesville
Oologah
Tulsa
Oklahoma City
We hopped in a car and drove 40 miles from Bartlesville to
Oologah, Oklahoma. Oologah is the birthplace of Will Rogers,
and is also the home of the Public Service Company of
Oklahoma’s Northeast Power Plant.
Exterior View of Generators
As you approach the plant, you can see two natural-gas-fired
generators to the left of the smokestack. To the right are two coalfired generators.
Entry Phone
At the plant entrance, Mr. Meador calls the plant
superintendent, asking permission to enter.
Hard Hats
Plant superintendent Gary Briggs outfitted us with hard hats
so that we could tour the 1.5 billion watt facility.
Coal Car Dumper
The first stop is the
coal car dumper,
where 110 train cars a
day bring in low-sulfur
coal from Wyoming.
The cars are turned
upside-down and the
coal is carried by a
conveyor belt to a
large storage yard.
Lab
Samples of the incoming coal are sent to this on-site lab and
analyzed for impurities and energy content. Wyoming coal has
less energy content than the native Oklahoma coal; however,
Oklahoma coal has more sulfur, which contributes to acid rain.
Coal Storage Yard
Back in the coal storage yard, a 60-day reserve supply is
maintained. In 1994, this entire reserve was used up, because of
train delays due to floods. PSO responded by buying electrical
power from other utilities. Power plants across the United States
are interconnected, so that they can buy and sell power between
each other.
Coal Compaction
The coal in the storage yard is compacted, to reduce dust and
keep air away from the coal. Otherwise, spontaneous
combustion could occur.
Coal Scooper
Coal is fed into the plant by shoveling it over to this giant
machine, which scoops is up onto a conveyor belt.
Coal Conveyor
The conveyor belt carries the coal up to the top of the plant.
Boiler Exterior
There the coal is
crushed to the
consistency of talcum
powder and blown by
air into a fifty foot tall
boiler.
Boiler Fire
The purpose of any power plant boiler is to heat water into steam.
Here we see Briggs by one of the plant's coal boilers. It burns
coal to heat water to 1000 degree Fahrenheit steam. Not all of
the coal entering the boiler can be burned. The unburned heavy
ash falls to the bottom of the boiler and is removed and used for
road base and cinder blocks.
Smokestack
The lighter fly ash goes up
the smokestack, where it is
given a negative charge and
drawn off by an electrostatic
precipitator. This material is
used in concrete and
cement.
Turbine (intact)
The steam from the boiler is sent to the power plant's turbine.
Turbine (dismantled)
One of the plant's turbine/generator systems was being
dismantled for maintenance, so we were able to inspect some of
its parts.
Steam from the boiler pushes against the fan blades of the
turbine. This turns a shaft leading into the generator. Magnets on
the end of the shaft spin inside a coil of wire to create the
electricity.
Adapted from a diagram by the Tennessee Valley Authority
Plant Diagram
Turbine Blades
Here are the fan blades in the turbine which are rotated by the
steam.
Coil
Magnets attached to one end of the spinning turbine shaft rotate
inside this giant coil of wire. The spinning magnetic field pushes
the electrons in the wire, creating the electrical current.
Turbine piping
The generators must be cooled or they will crack. Cooling water
from Lake Oologah is pumped through these tubes in the 10-inch
thick generator walls. 200,000 gallons of water flow through these
tubes each minute.
Cooling Towers
To prevent environmental damage, this water must be cooled
before it is returned to the lake. It is pumped to cooling towers,
where some of the water evaporates, which cools the remaining
water. The clouds of steam we see rising above the power plant
are this evaporated water.
Control Room
Here we see the control room, from which the entire plant is
monitored. To protect the power plant's equipment, start-ups and
shut-downs must be done carefully and slowly. This power plant
actually cannot start up on its own, but must borrow power from
another plant to pre-heat its generator.
If the power plants needs to shut down,
the large batteries shown here provide
the power for a controlled stop.
Battery Room
Transformers
The plant’s generator produces electricity at 22,000 volts.
Step-down Transformer
One large transformer outside the plant steps the voltage down to
5,000 volts. This power is used to run the plant’s fans as well as
the electromagnets inside the generator.
Step-up Transformer
A second transformer outside the plant connects the generator to
the cross-country power lines. It steps the voltage up, from
22,000 volts to 345,000 volts. This high voltage lowers the current
in the cross-country lines, which reduces energy loss.
Switchyard
The high voltage electricity is sent to the switchyard, where it is
routed to various cities.
Outbound Line
Having completed
our tour, we leave the
plant and trace an
outbound line which
leads to a city's
substation.
To minimize weight,
electrical power lines
are not covered with
insulation; they are
bare wire.
Substation
A cross-country power line
feeds into this substation near
Tri-County Tech in Bartlesville.
The substation has giant circuit
breakers as well as step-down
transformers which lower the
voltage to 13,800 volts for citywide distribution.
City Line
Here is a city power line.
The top wire carries no
current, because it tends
to be struck by lightning.
The three wires below it
carry higher voltage
electricity across town.
Three smaller wires below
those carry lower voltage
electricity to nearby
neighborhoods.
The lowest wires on the
line are for phone and
cable television service.
Pole Transformer
Here we see a polemounted neighborhood
transformer. It lowers
the 13,800 volts from
the city power line to
120 volts for use in
homes and businesses.
Ground Transformer
Here Ms. Shaw
inspects another
type of
transformer,
used in
neighborhoods
with belowground wiring.
House Meter
And at last we
reach a home or
business, where the
amount of electrical
energy being used
is measured by a
meter.
Pole Painting
And that concludes our special report on electrical power
generation. Now you know what is on the other end of a
power line.
Electrical Power
Generation
Special thanks to the
Public Service Company of
Oklahoma and Gary Briggs
Power Plant Diagram adapted from original art by the
Tennessee Valley Authority
www.bhsphysics.org