Electrical power generation and distribution

1. EEC 122
PRINCIPLE OF ELECTRICAL ENERGY
GENERATION

2. INTRODUCTION
Energy is the basic necessity for the economic development of a
country due to it importance in human life. Most of our day to day
activities make use of electrical energy because it makes the activity
much easier, simple within a limited time. It is practically impossible to
estimate the actual magnitude of the part that electrical energy has
played in the building up of present day civilization. With the advance
or the availability of huge amount of energy in the modern times has
resulted in a shorter working day, higher agricultural and industrial
production, a healthier and more balanced diet and better
transportation facilities. As a matter of fact, there is a close
relationship between the energy used per person and his standard of
living. The greater the per capital consumption of energy in a country,
the higher is the standard of living of its people.

3. IMPORTANCE OF ELECTRICAL ENERGY
The energy exist in different forms in native but the
most important form is the electrical energy. The
modern society is so much dependent upon the use
of electrical energy in the sense that, it has become
a part and parcel of our life. The present-day
advancement in science and technology has made it
possible to convert electrical energy into any
desired form. In fact, the advancement of a country
is measured in terms of per capital consumption of
electrical energy. Electrical energy is higher to all
other form of energy due to the fact that electrical
energy is;

4. Electrical energy is higher to all other form of
energy due to the fact that electrical energy is;
1. Convenient in form
2. Easy control
3. Greater flexibility
4. Cheapness
5. Cleanliness
6. Higher transmission efficiency.

5. GENERATION OF ELECTRICAL ENERGY
(ELECTRICITY GENERATION)
Electricity generation is the process where energy
available in different forms in nature is being converted
into electrical energy. The electrical energy must be
produced and transmitted to the point of use at the
instant it is needed.
SOURCES OF ENERGY
1. Sun
2. Wind
3. Water
4. Fuels
5. Nuclear energy

6. sun
The sun is a primary source of energy. The heat
energy radiated by the sun can focused over a
small area by means of reflectors. This heat can
be used to raise steam and electrical energy can
be produced. This system has some limitations
such as:
1. It cannot be used in cloudy days or at night
2. It is an uneconomical method due to high
initial costs.

7. Wind
This method can be used where wind flows for a
considerable length of time. Wind energy is used to run
the wind mill continuously and this is used to charge
batteries. This batteries supply the energy when the wind
stops. This method has the advantages that maintenance
and generation costs are negligible. However, the draw
backs or disadvantages of this method are;
1. variable output.
2. unreliable because of uncertainty about wind
pressure.
3. power generated is quite small.

8. Water
When water is stored at a suitable place, it
possesses potential energy because of the head
created. This water energy can be converted
into mechanical energy with the help of water
turbines. The water turbines drive the alternator
which converts mechanical energy into electrical
energy. This method or generation of electrical
energy has become very popular because it has
low production and maintenance costs.

9. Fuels
This can be further classifying into solid fuel
(coal), liquid, fuel (oil) and gas fuel (Gas). The
heat energy of these fuels is converted into
mechanical energy by suitable prime movers
such as steam engines, steam turbines, internal
combustion engine etc. The prime mover drives
the alternator which converts mechanical
energy into electrical energy.

10. Nuclear energy
It has been discovered that large amount of heat energy
is liberated by the fission of uranium and other
fissionable materials. It is estimated that heat produced
by 1kg of nuclear fuel is equal to that produced by 4500
tones of coal. The heat produced due to nuclear fission
can be utilized to raise steam with suitable arrangements.
The steam can run the steam turbine which then drives
the alternator to produce electrical energy. The
disadvantages of this system are;
1. High cost of nuclear plant
2. Disposal of radioactive waste and death of trained
personnel to handle the plant.

11. GENERATING STATION
Bulk electric power is produced by special plants
known as generating stations or called power
plants. A generating station essentially employs a
prime mover coupled to an alternator for the
production of electric power. The prime mover (e.g.
steam turbine, water turbine etc.) converts energy
from some other form into mechanical energy. The
alternator converts mechanical energy of the prime
mover into electrical energy. The electrical energy
produced by the generating station is transmitted
and distributed with the help of conductors to
various consumers.

12. Depending upon the form of energy being
converted into electrical energy, the generating
stations are classified as:
1. Steam power plants
2. Hydro power plants
3. Diesel power plant/Gas power plant
4. Nuclear power plants
5. wind power plant
6. Solar power plant

13. STEAM POWER STATION (THERMAL
STATION)
A generating station which converts heat energy of
coal combustion into electrical energy is known as a
steam power station. The steam is produced in the
boiler by utilizing the heat of coal combustion. The
steam is then expanded in the prime mover (i.e.
steam turbine) and is condensed in a condenser to
be fed into the boiler again. The steam turbine
drives the alternator which converts mechanical
energy of the turbine into electrical energy. This
type of power station is suitable where coal and
water are available in abundance and a large
amount of electric power is to be generated.

14. A steam power station utilizes heat energy
produced from burning coal to generate
electrical energy. This kind of power station is
generally used around the world. Because of the
wealth of fuel (coal), this set of the power
station can be used to generate large amounts
of electrical power.

15. Factors to determine the Site of Steam
Power Station
Steam-powered power stations keep on working very close to
full efficiency for 24 hours a day. Power plants have a standard
life of 30 to 40 years. The following is a record of factors that
affect the selection of a site for building a Steam power
station:
1. Supply of fuel
2. Nature of land and its price
3. Availability of water
4. Transportation facilities
5. Cost and type of land
6. Distance from populated areas
7. Nearness to load centers

16. Supply of fuel
Steam Power Station must be placed close to
coal mines to lessen the transportation cost of
fuel. Steam power plant using coal or oil as fuel
needs a very large amount of fuel per annum.

17. Nature of land and its price
The chosen site should have a high bearing
capability of at least 10 N/sq mm to withstand
the dead weight of the plant. It would lessen the
cost of the base of the plant.

18. Availability of water
The station must be positioned near a river bank
or canal for constant water supply. The steam
power plant utilizes water as a working solution
throughout the year, which is regularly
evaporated and condensed. It also wants about
2% of the steam produced as makeup water due
to its loss.

19. Transportation facilities
The station must be well attached to important
transport routes eg Rail or Road. A new steam
power plant often needs the transportation of
material and machinery. Therefore, sufficient
transportation facilities must exist i.e. the plant
should be well attached to other parts of the
land by rail, road. etc.

20. Cost and type of land
The land must have a great bearing capacity for
heavy machinery and yet be affordable enough
to purchase. The steam power plant should be
located at a point where the property is cheap
and further expansion, if needed, is possible.
Furthermore, the carriage capacity of the area
should be enough so that heavy machinery
could be installed.

21. Distance from populated areas
The station must be established as far away
from populated areas as possible due to air
contamination.

22. Nearness to load centers
In order to decrease the transmission cost, the
plant should be placed near load centers. The
location of the factory at the center of loads
lessens the cost of transmission channels and
the losses occurring in it.

23. Advantages of Steam Power Station
1. It needs low initial investment and less time
to commission plant.
2. The cost of the Steam power plant is lower
than several power plants.

24. Disadvantages of Steam Power Plant
1. Transport of fuel is a major problem.
2. Cost of power generation is higher than
hydropower.
3. Air pollution is a major difficulty.
4. Coal may be depleted by gradual use.

25. The efficiency of Steam Power Stations
The overall efficiency of the steam power station
is very average (about 29%) mainly due to two
reasons. First, a large amount of heat is lost in
the condenser and secondly, heat losses happen
at different stages of the plant. The heat loss in
the condenser cannot be withdrawn. It is
because heat energy cannot be transformed into
mechanical energy without temperature
difference.

26. Main Component on Steam Power
Plant
1. Steam boiler: The boiler has the capacity to convert
water into steam. The process of change of water to
vapor is produced by heating the water in the tubes
with energy from burning fuel. The combustion
process is carried out continuously in the combustion
room with fuel and airflow from the surface. The
resulting steam is superheated fumes which have high
temperature and high pressure. The size of steam
production depends on the surface area of heat
transferal, flow rate, and the heat of combustion is
applied. Boiler system consisting of water-filled pipes
is called a water tube boiler.

27. Main Component on Steam Power
Plant
2. Steam Turbine: The steam turbine works to
change the heat energy carried in the steam into
rotary motion. Steam with high load and
temperature were conducted to push turbine
blades installed on the shaft, so the shaft turns.
Due to complete work on the turbine, the
pressure and heat of steam coming into the
turbine down to drenched vapor. This steam
then proceeds to the condenser, while the
whirling power is used to turn a generator.
Today nearly all of the steam turbine is a kind of
condensing turbine.

28. Main Component on Steam Power
Plant
3. Condenser: Condensers are tools to convert
steam into water. The changes are made by
the steam flow into a room holding tubes.
Steam runs outside tubes, while the cooling
water flows inside the tubes. This is called
surface condenser. It is usually for coolant
use seawater.

29. Main Component on Steam Power
Plant
4. Alternator: The steam turbine copulates to
an alternator. When the turbine turns the
alternator, electrical energy is produced. This
generated electrical voltage is then walked
up with the help of a transformer and then
transferred where it is to be employed.

30. Main Component on Steam Power
Plant
5. Generator: The main idea of the activities at
a plant is electricity. The electrical energy is
produced by the generator. Function
generator converts mechanical force into
electrical energy in the form of a circle with
the origin of magnetic induction. The
generator consists of stator and rotor. The
stator consists of the casing which holds coils
and a rotor magnetic field station consists of
a core comprising a coil.

31. Working system of steam power
Station
Working fluid cycle of the steam power plant is a final cycle, which
uses the same fluid regularly. First, the water is loaded into the boiler
to fill the whole surface area of heat transfer. In the boiler, water is
warmed by the hot gases of combustion fuel with air so that it gets
transformed into the vapor phase. Steam generated by boiler with
pressure and temperature is guided to do work on the turbine to
provide mechanical power in the order of rotation. The former steam
out of the turbine and then moved into the condenser to be frozen
with cooling water that converted to water. Condensate water is then
utilized again as boiler feed water. Thus the cycle continues on and
repeats. Rotation of the turbine is utilized to turn a generator that is
linked directly to the turbine. So when the turbine revolves, the
generator output terminals produce electricity. Although the working
fluid series is a closed cycle, the amount of water in the cycle would
decline. The loss is due to the leakage of water either deliberately or
accidentally.

32. Questions
What are the components of a Steam Power
Plant?
What are the principal works of a steam power
plant?
What is the definition of a Steam Power Plant?