Download ichLarge quantities of electrical energy are produced in power

ichLarge quantities of electrical energy are produced in power stations by using the principle
of induction. Where does all this energy come from?
Simply put, the root source of a power station’s energy depends on what type of power station/
plant it is. That is being said, large generators that have coils moving between magnets produce
nearly all electricity from a power station. An electric generator is a device specifically designed
to convert mechanical energy into electric energy efficiently. Large rotors are rotated by strong
magnetic fields. This process can be continued indefinitely by rotating the coil, which, in turn,
changes the magnetic flux.
The rotating coil rotates with the angular speed ω. The electromagnetic force, or emf, produced
by the rotating coil, can be explained by utilizing Faraday’s Law:
ε = -N (Δ Φ/Δt)
The induced emf in the coil alternates in direction; this type of generator is known as an
alternating-current generator or ac generator. One can see that the rate of change of the
magnetic field is proportional to the magnitudes of the induced current and induced emf. In
other words, the more rapidly the magnetic field changes, the greater the emf induced. The use
of transformers increases the voltage in a power plant by a factor of 15, as our textbook states:
“from 10,00 v to 150,000 v)” (Walker, 824).
(An illustration of electromagnetic induction.
Source: http://www.scienceclarified.com/El-Ex/ElectromagneticInduction.html#ixzz0S5yZZN3z )
We know that energy is produced from wire coils turning between magnets, but from where
does the energy to turn the coils come? The answer to this question, as stated before, is found
in what the root source of the power station’s energy is. In the normal process of electric
generator, a device or motor is used for converting the kinetic energy into electric energy using
the principle of electromagnetic induction.
There are several different types of energy sources for power stations:
Hydroelectric Power:
This type of power utilizes the gravitational potential energy of water and transforms it into
kinetic energy. The larger hydroelectric plants use dams to regulate the flow of water. When
water is released from the dam, the turbines spin at high rate of speed and produce an electric
current into the coil placed between the poles of magnet as shown in above diagram.
Transformer is also applied to change the electric current from one voltage to another voltage
as high voltage current produced in power plant is much higher than what we use is daily
appliances of household operations. A step down transformer converts in to voltage suitable
for home electric equipment.
Steam Power:
Steam can be used to push turbines. Common ways to create steam are by coal or natural gas.
A coal-fired plant, for example, uses steam to push turbines, thus generating an electric current
into the coil.
Electrical
Energy
Mechanical
Energy (fossil, hydro,
Energy
Prime Mover
Energy
Electric Generator
nuclear, etc)
(Diagram for generating Electric energy using prime Mover)
(Source: http://www.vocw.edu.vn/content/m11419/latest/chapter%201.pdf )
Prime mover is the source of mechanical energy as we are discussing for each type of power
plant. It gets converted into electrical energy either through direct conversion as in the case of
nuclear power or indirect conversion by first producing kinetic energy and then convert it into
electrical energy.
Nuclear Power:
The nuclear energy produced inside the sun's core is the sun's energy. The mass is the source of
nuclear energy produced during fusion reactions in the sun's core.
A nuclear reactor is used to convert mass to energy through fission reactions. Within these
fission reactions, the large nuclei, such as those of uranium, are split into smaller fragments. This
process produces enormous amounts of energy through heat, which is then used to make steam.
The steam, in turn, is used to generate an electric current into the coil.
Wind Power:
While waterpower has been used longer, windmills have been use to generate power for over
1,400 years. Wind turbines turn in the moving air and power an electric generator, which
supplies an electric current to the coil. As the wind turns the blades, this causes a shaft,
connected to a generator, to spin and produce electricity. A wind turbine is the opposite of a
fan, using wind to make electricity instead of using electricity to make wind.
Solar Power:
The sun’s light contains energy and, usually, when the sun hits an object or body that energy
turns into heat. However, when the sun’s light hits a solar panel or cell, that energy is turned
into solar power, and then into an electrical current.
Similarly, solar thermal plants use giant mirrors to harness the suns energy by reflecting the
sunlight back to a tower, and rays turn water into steam, which generates power by turning the
turbines.
In each of these cases, the rotation of the turbine rotates the generator rotor to produce
electricity based on Faraday’s principle of electromagnetic induction.
Conclusion
As we have discussed the different methods of electricity generation which shows the basic
principle remains same at the core of each power plant. In each of power plant, an
electromagnetic energy converter turns the mechanical energy into electrical energy by
modulating the response to electric signal depending on the value of rotational speed of
turbine. “Electromechanical power is evaluated by the formula Pmech=Mωm = vi=Pelectrical
Where
M is mechanical torque (N-m), ωm is mechanical angular velocity (rad/s),
v is instantaneous electrical volts (volts),
and i is instantaneous electrical current (amperes)”.
(source : http://www.vocw.edu.vn/content/m11419/latest/chapter%201.pdf )
All these generators work on the Faraday's law of electromagnetic induction where electromotive force
(emf) is induced along the magnetic lines of flux in conductor.