Electrical Engineering Guide to Energy Sources

Introduction to Electrical Engineering 22ESC142 2023
DEPT.OF EEE,AMCECDepartment of EEE,AMCEC,Bangalore 1
MODULE-1
INTRODUCTION
ENERGY SOURCES
The energy of a body is its capacity to do work. It is measured the total
amount of work that the body can do. Energy is the ability of a physical system to
perform work. We use energy in our daily lives from various sources for doing
work. We use muscular energy for carrying out physical work, electrical energy
for running multiple appliances, chemical energy for cooking food, etc. For this,
we need to know the different energy sources to obtain energy in its usable form.
Different forms of energy:
The different forms of energy are:
1. Mechanical energy (kinetic and potential)
2. Thermal (or) Heat energy
3. Chemical energy
4. Electrical energy
5. Nuclear energy
6. Electromagnetic energy
7. Gravitational energy
Primary Energy Sources:
Primary energy sources can be defined as sources which provide a net
supply of energy Coal, Oil, Uranium etc., are examples of this type. The energy
required to obtain these fuels is much use than what they can produce by

combustion or nuclear reaction. The supply of primary fuels is limited. It
becomes very essential to use these fuels sparingly. Examples: Coal, natural gas,
oil and nuclear energy.
Secondary Energy sources:
Secondary fuels produce no net energy. Though it may be necessary for the
economy, these may not yield net energy. Secondary sources are like sun, wind,
water (tides), etc. Solar energy can be used through plants, solar cells, solar
heaters and solar collectors.
Supplementary sources: are defined as those whose net energy yield is zero and
those requiring highest investment in terms of energy Insulation (thermal) is an
example for this source.
Energy Consumption as a Measure of Prosperity:
Energy is an important input in all sectors of any country’s economy. The
standard of living of a given country can be directly related to per capita energy
consumption. The per capita energy consumption in U.S.A. is 8000 kWh per
year, whereas the per capita energy consumption in India is 150 kWh U.S.A.
with 7% of world’s population consumes 32% of the total energy consumed in
the world, whereas India, a developing country with 20% of the world’s
population consumes only 1% of the total energy consumed in the world.
Therefore one might conclude that to be materially prosperous, a human being
needs to consume more and more energy than his own.
What Constitutes an Energy Crisis?
Energy crisis is a situation in which the nation suffers from a disruption of
energy supplies (in our case, Oil) accompanied by rapidly increasing energy
prices that threaten economic and national security. With the international crude
oil prices hovering around $ 125 per barrel and the oil import bill set for a jump
of over Rs. 537 billion to reach over Rs. 2727 billion this year, India is heading
for a major energy crisis. With a population of around 113 crore, we cannot
afford to follow the high-energy consumption pattern of the West that has
resulted in an indiscriminate exploitation of fossil fuels and high pollution levels.
The situation will aggravate if necessary steps are not taken in time. According to

Dr. Rajendra K Pachauri, Director-General, The Energy and Resources Institute
(TERI) ‘The lack of any comprehensive national energy policy, inadequate public
transport system and disregard of domestic renewable energy resources has led
to the present energy crisis”.
Conventional and Non-conventional Sources of Energy
Conventional sources of energy
Conventional sources of energy are the natural energy resources which are
present in a limited quantity and are being used for a long time. They are
exhaustible like Coal, Petroleum etc.
Non-conventional sources of energy are the energy sources which are
continuously replenished by natural processes.
Energy is the ability of a physical system to perform work. We use energy in our
daily lives from various sources for doing work. We use muscular energy for
carrying out physical work, electrical energy for running multiple appliances,
chemical energy for cooking food, etc. For this, we need to know the different
energy sources to obtain energy in its usable form.
Sources of Energy
The two major sources of energy is classified as:
• Conventional Sources
• Non-Conventional Sources

The classification of the sources of energy is given in the below image.
Conventional Sources of Energy
Conventional Sources of Energy are also known as non-renewable sources of
energy and are available in limited quantity apart from hydro-electric power.
Further, it is classified under commercial and non-commercial energy.
Commercial Energy Sources
Coal, electricity and petroleum are known as commercial energy since the
consumer needs to pay its price to buy them.
Coal
Coal is the most important source of energy. There are more than 1,48,790 coal
deposits in India, and between 2005-2006, the annual production went up to
343 million tons. India is the fourth-largest coal-producing country, and the
deposits are primarily found in Bihar, Orissa, Madhya Pradesh, Jharkhand and
Bengal.
Oil and Natural Gas
Oil is considered liquid gold and one of the crucial energy sources in India and
the world. Oil is primarily used in planes, automobiles, trains and ships. The total

oil production in India was 0.3 million tons in 1950-51, which increased up to
32.4 million tons in 2000-01. It is mainly found in Assam, Gujarat and Mumbai.
Electricity
Electricity is a common form of energy used for domestic and commercial
purposes, and it is mainly utilized in electrical appliances like fridges, T.V,
washing machines and air conditioning.
The major sources of power generation are:
• Nuclear Power
• Thermal Power
• Hydro-electric power
Thermal Power: Thermal power is generated at various power stations utilizing
oil and coal. It is a vital source of electric current, and its share in the nation’s
total capacity in 2004-05 was 70 percent.
Hydroelectric Power: Hydroelectric power is produced by constructing dams
above flowing rivers like Damodar Valley Project and Bhakra Nangal Project. The
installed capacity of hydroelectric power was 587.4 MW in 1950-51 and went
up to 19600 MW in 2004-05.
Nuclear Power: The fuel used in nuclear power plants is Uranium, which costs
less than coal. Nuclear power plants can be found in Kaiga (Karnataka), Kota
(Rajasthan), Naroura (UP) and Kalapakam(Chennai).
Non-commercial Energy Sources
Generally, the freely available energy sources are considered non-
commercial energy sources. Examples of non-commercial energy sources include
straw, dried dung, firewood.
Non-Conventional Sources of Energy

Non-conventional sources are also known as renewable sources of energy.
Examples of non-conventional sources of energy include solar energy, bioenergy,
tidal energy and wind energy.
Solar Energy
Solar Energy is produced by sunlight. The photovoltaic cells are exposed to
sunlight based on the form of electricity that needs to be produced. The energy is
utilized for cooking and distillation of water.
Wind Energy
Wind energy is generated by harnessing the power of wind and mostly used in
operating water pumps for irrigation purposes. India stands as the second-largest
country in the generation of wind power.
Tidal Energy
Tidal energy is generated by exploiting the tidal waves of the sea. This source is
yet to be tapped due to the lack of cost-effective technology.
Which is the largest non-conventional source of energy?
The largest non-conventional source of energy is solar energy.
Conventional Energy sources Non-Conventional Energy sources
These sources of energy are also
known as a Non-Renewable source
of energy.
These sources of energy are also
known as a Renewable source of
energy.
They find both commercial and
industrial purposes.
They are mainly used for household
purposes.
These can be considered to be one
of the reasons for the cause of
pollution.
These are not responsible for the
cause of pollution.
Coal, fossil fuels are two examples Wind, solar energy and Biomass two
examples

Advantage
The efficiency and the production
expenses of the conventional
energy sources are low
Advantage
Non-conventional sources of energy
are environmentally friendly,
inexhaustible and easy to operate.
Dis-advantage
Conventional energy sources are
not environmentally friendly and
it can deplete soon.
Importance
Non-conventional sources of energy
are considered to be important as
they are renewable, pollution-free,
availability of them is in abundance,
and they are environmentally
friendly.
Conventional and non-conventional sources energy
Conventional energy sources are:
(a) Fossil fuel energy (b) Hydraulic energy (c) Nuclear energy
(a)Fossil fuel energy:
Coal, petroleum, and natural gas are called Fossil fuel as these are formed by the
decomposition of the remains of dead plants and animals buried under the earth
for a long time. These are non-renewable sources of energy, which, if exhausted,
cannot be replenished in a short time. Their reserves are limited and are
considered very precious. These should be used with care and caution to let them
last long. These are also contributing to the global environmental pollution.
Wood was dominant source of energy in the pre-industrialization era. It gave
way to coal and coke. Use of coal reached a peak in the early part of the
twentieth century. Oil gets introduced at that time and has taken a substantial
share from wood and coal. Wood is no more regarded as a conventional source.
Hydroelectricity has already growth to a stable level in most of the developed
countries.
Coal :
India now ranks third amongst the coal-producing countries in the world. Coal is
the most abundant fossil fuel in India till date and coal has been the mainstay of
India’s energy supply for many years. Production of coal has increased from

about 71 MT (million tones) in the early 19705 to 407 MT in 2005-06 (MOC
2007). Indian coal is of poor quality and has high ash content Since the advent of
industrialization coal has been most common source of energy. In the last three
decades, the world switched over from coal to oil as a Major source of energy
because it is simpler and cleaner to obtain useful energy from oil. Coal is a
complex mixture of compounds of carbon, hydrogen and oxygen. Small amounts
of nitrogen and Sulphur compounds are also present in coal. It is mainly
available in Bihar, West Bengal, Orissa and Madhya Pradesh. The big coal mines
in our country are at Jharia and Bokaro in Biharand at Raniganj in West Bengal.
It is considered as the backbone of the energy sector for its use in industry,
transportation and electric power generation.
According to estimates coal is abundant. It is enough to last for 200 years.
However, it is low in calorific value and its transportation is expensive. Coal is
pollutant and when burnt it produces CO2 and CO. Extensive use of coal as a
source of energy is likely to disturb the ecological balance of CO2 since global
warming will takes place due to large proportions of carbon dioxide produced by
burning large quantities of coal.
Petroleum Oil:
The 40% of the energy needs of the world are fed by oil. It is a dark coloured,
viscous and foul smelling crude oil. The petroleum means rock oil. It is normally
found under the crust of earth trapped in rocks. The crude oil is a complex
mixture of several solid liquid gaseous hydrocarbons mixed with water, salt and
earth particles. It is a natural product obtained from oil wells.
With today’s consumption and a resource amount of 250,000 million tones of
oil, it would suffice for about 100 years unless more oil is discovered. Some of the
crude oil producing locations in our country are: (i) Ankleshwar and Kalol in
Gujarat
(ii) Rudrasagar and Lakwa in Assam; and
(iii) Bombay high (off-shore area)
The oil wells of Bombay high are producing about 22 million tons of crude
petroleum oil per year, which is little less than half of the total requirement of the

country. The efforts are also being made to search oil well in off-shore deltas to
Godavari, Kaveri, and Rajasthan.
Natural gas:
It consists about 95% Methane and rest ethane and propane. It occurs deep
under the crust of the earth either alone or a long with oil above thepetroleum
deposits. It is a product of petroleum mining. The gas is available in Tripura,
Jaisalmer, off-shore areas of Bombay High and in the Krishna – Godavari delta. It
is used as a domestic and industrial fuel. The natural gas is now also available as
CNG (Compressed Natural Gas) a substitution of petrol in automobiles. Gas is
incompletely utilized at present and huge quantities are burnt off in the oil
production process because of the non-availability of ready market. The reason
may be the high transportation cost of the gas. To transport gas is costlier than
transporting oil. 13 The production of natural gas increased f

POWER GENERATION
Hydroelectric Power Plant
Hydroelectric power plant
It is becoming very popular nowadays to full feel rapid increasing demand
of electric power day by day. Every country is trying to develop more Hydro
Electric Power Station to full fill their demand for electricity. In other hand
fossils, fuels (i.e. coal, oil, and gas) are limited stock in the world and these fuels
are expensive. So hydroelectricity may be a good alternative electrical source. So
in a single word we can say, a generating Station which utilizes the potential
energy of high-level water for the generating of electrical energy is known as
hydropower plant or hydroelectric power plant.
WORKING PRINCIPLE OF HYDROELECTRIC POWER PLANT
Working principle of hydroelectric power plant depends on the conversion of
hydraulic energy into electrical energy. To get this hydroelectricity, hydroelectric
power plant needs some arrangements for proper working and efficiency. The
block diagram of hydroelectric power plant is shown below:

• Hydroelectric power station needs huge amount of water at sufficient head
all the time. So a hydroelectric dam is constructed across the river or
lake.An artificial storage reservoir where water is stored, is placed back
side of the dam. This reservoir creates sufficient water head.
• A pressure tunnel is placed in between the reservoir to valve house and
water is coming from reservoir to penstock via this tunnel.
• An automatic controlling sluice valve is placed in valve house and it
controls water flow to the power station and the letter cuts off supply of
water in case the penstock bursts.
• Penstock is a huge steel pipe in which water is taken from valve house to
turbine.
• A surge tank is also provided just before the valve house for better
regulation of water pressure in the system.
• Now water turbine converts hydraulic energy into mechanical energy and
an alternator which is couple to the water turbine converts this mechanical
energy into electrical energy.

ADVANTAGES & DISADVANTAGES OF HYDROELECTRIC POWER PLANT
Advantages
There are lots of advantages in Hydroelectric Power Plant:
1. Since water is the main source of energy, so no fossil fuels are required.
2. This plant is neat and clean and no smoke or as disposal is required.
3. It is the cheapest operating and maintenance cost as compared to the other
power plants because water is freely available in the world.
4. It is very reliable, robust and has a longer life app rocks 45 to 60 years.
5. This plant can start instantly.
6. It can start hydroelectric power with fluctuating load demand.
7. The efficiency does not fall at the age of this plant.
8. There is no standby loss in this plant.
9. At the initial time of construction highly skilled engineers are required and
after that only few experience persons can run the plant.
10. This plant also serves to help in irrigation and Flood control etc.
11. Since this plants are located remote area so land is available and
competitively cheaper rates.
Disadvantages
There are some Disadvantages in hydro power plant:
1. Such plant requires large area
2. High construction cost is required due to construction of dam.
3. When experience skilled engineers are required to build this plant

4. Scenes such plant is located as from the load areas, long transmission line is
required to transmit this hydroelectric power.
5. It doesn't supply constant hydroelectricity due to the availability of water. In
transition, power supply is most affected.
SITE SELECTION FOR HYDROELECTRIC POWER PLANT
1. Water Availability:
Main fuel of this plant is water. So, such plant should be located nearer to river,
canal etc. where sufficient water is available all the time.
2. Water Storage:
Storage of water in a suitable reservoir or dam has to be placed by a careful
geological study of the area to get the maximum advantage of that water.Dam
should be located across the river to get continuous water supply throughout the
year specially in a dry season.The storage capacity of dam can be determined by
hydrograph or mass curve or using analytical method.Adequate facilities of
erection a dam and storage of water are two important matters for site selection
of hydro electric power plant.
3. Water Head:
It is an important point for site selection of hydroelectric power plant.Water head
is directly related to the cost of generation of electric power.If effective head is
increased,water storage has to be reduced as well as capital cost of the plant is
reduced.
4. Distance from the load center: Since it is located away from the load center,
more transmission line is required to supply the power. To avoid the line loss and
economic power supply, distance of such plant should need more attention.
5. Transportation Facilities:
Good transportation facilities must be available to any hydroelectric power plant,
so that necessary equipment should be reached easily.
6. Availability of land:

Hydroelectric power plant needs enough space. It should be kept in mind that
land cost must be cheap.

Nuclear Power Plant
Working Principle of Nuclear Power Plant
The working principle of nuclear power plant depends upon mainly four
components.
1. Nuclear Reactor
2. Heat Exchanger
3. Steam Turbine
4. Alternator
Nuclear reactor is used to produce heat and heat exchanger performs to convert
water into steam by using the heat generated in nuclear reactor. This steam is fed
into steam turbine and condensed in condenser. Now steam turbine is turn to run
an electric generator or alternator which is coupled to steam turbine and thereby
producing electric energy. This is a very basic working principle of Nuclear
power plant. Here is the detail operation of the individual unit of this plant.
The block diagram of nuclear power plant shown in figure:-

1. Nuclear Reactor:-
Nuclear reactor is the main component of nuclear power plant and nuclear fuel
is subjected to nuclear fission. Nuclear fission is a process where a heavy nucleus
is spitted into two or more smaller nuclei. A heavy isotope generally uranium-
235(U-235) is used as a nuclear fuel in the nuclear reactor because it has the
ability to control the chain reaction in the nuclear reactor. Nuclear fission is done
by bombarding uranium nuclei with slow moving neutrons. The energy released
by the fission of nuclei is called nuclear fission energy or nuclear energy. By the
braking of uranium atom, tremendous amount of heat energy and radiation is
formed in the reactor and the chain reaction is continuously running until it is
controlled by a reactor control chain reaction. A large amount of fission neutrons
are removed in this process, only small amount of fission uranium is used to
generate the electrical power.
BLOCK DIAGRAM OF NUCLEAR REACTOR:

The nuclear reactor is cylindrical type shape. Main body of reactor is enclosed by
reactor core, reflector and thermal shielding. It prevent reactor wall from getting
heated. It is also used to protect alpha ( α), bita (β) , gama (γ) rays and neutrons
which are bounce back at the time of fission within the reactor. Mainly Nuclear
reactor consists, some fuel rods of uranium, moderator and control rods. Fuel
rods are made of the fission materials and released large number of energy at the
time of bombarding with slow moving neutrons. Moderator consists full of
graphite which is enclosed by the fuel rods. Moderator maintains the chain
reaction by releasing the neutrons in a suitable manner before they mixed with
the fissile materials. Control rods are made of boron-10 and cadmium or
hafnium which is a highly neutron absorber and it is inserted into the nuclear
reactor. When control rods are push down into the reactor core, it absorbs most
of fission neutrons and power of the reactor is reduced. But when it is pulling out
from the reactor, it releases the fission neutrons and power is increased. Real
practice, this arrangement depends upon according to the requirement of load. A
coolant, basically sodium metal is used to reduce the heat produce in the reactor
and it carries the heat to the heat exchanger.
2. Heat Exchanger:-
Coolant is used to raise the heat of the heat exchanger which is utilized in raising
the steam. After that, it goes back to the reactor.

3. Steam Turbine:-
Steam is coming from the heat exchanger to feed into the steam turbine through
the valve. After that the steam is exhausted to the condenser. This condensed
steam is fed to the heat exchanger through feed water pump.
4. Alternator:-
Steam turbine is coupled to an alternator which converts mechanical energy to
electrical energy. The output of alternator produces electrical energy to bus bars
via major electrical apparatus like transformer, circuit breakers, isolators etc.
Hydroelectric Power Plant or Hydroelectric Power Station
Hydroelectric power is developed from Hydroelectric Power
Plant or Hydroelectric Power Station. It develops hydroelectricity to utilize the
potential energy of water. In hydroelectric power plant, water is stored in a dam
called hydroelectric dam which is located upper level from the ground especially
any hilly areas. Water head is created by construction the dam across any river
or lake.This type of water head store huge potential energy. The water fall into
water turbine and the potential energy of water is converted into kinetic energy.
This kinetic energy is converted into mechanical energy at the turbine shaft.
A hydroelectric generator or alternator is coupled with turbine shaft to convert
mechanical energy into electrical energy.
The power P is developed-
Here,
W = Specific weight of water in kg/m3
Q = Rate of flow of water in m3/s
H = Height of fall or head in meters
η = Overall efficiency of operation

Solar Power Plant
Components of a Solar Electric Generating System
Solar Power systems are nothing but a system comprising of solar panels and the
other mechanism according to the various uses of the system for different
purposes. It mainly uses solar energy as the main power source for its operation.
The basic components of a solar power system includes:
1. PV Module,2. Inverter,3. Main Fuse Box, 4.Utility Meter and 5.Grid
• PV Modules
A PV module is nothing but a panel consisting of large number of solar cells that
stores the solar energy and convert it into electricity for further usage.
• Inverter
An inverter is a small set-up that has simple working principle of converting
Direct current(D.C.) to Alternating current(A.C.).
• Main Fuse Box:

It is a distribution box that supplies the power to different appliances according
to the requirement of individual appliances.
• Utility Meter:
A utility meter is defined according to its usage. The utility is in the form of
electricity, Gas, Water, Heat etc..
• Grid:
The Grid is a connection of Photovoltaic or PV modules used to generate more
and more electricity using solar energy. It consists of a large number of inverters
according to the number of panels connected in the grid.

Wind Power Plant
Wind turbines work on a simple principle:
instead of using electricity to make wind—like a fan—wind turbines use wind to
make electricity. Wind turns the propeller-like blades of a turbine around a
rotor, which spins a generator, which creates electricity.
Flow Diagram of a Wind Turbine System
Here,
1) Wind Turbine: Converts wind energy into rotational (mechanical) energy
2) Gear system and coupling: It steps up the speed and transmits it to the
generator rotor
3) Generator: Converts rotational energy into electrical energy.
4) Controller: Senses wind direction, wind speed, generator output and
temperature and initiates appropriate control signals to take control action.
There are two basic types of wind turbines (WT):
1. Horizontal axis wind turbines (HAWT) and

2. Vertical axis wind turbines (VAWT). Figures 6(a) and 6(b) show HAWT
and VAWT respectively.
Basic Components of Wind Energy Conversion System (WECS)
The wind-electrical generating power plant with its components is shown in
figure

Block diagram of components of a wind energy conversion system
I. Rotors
Basically there are two types of rotor
a) Horizontal axis rotor
b) Vertical axis rotor
II. Wind Mill Head:
The wind mill head performs the following functions
a) It supports the rotor housing and the rotor bearing.
b) It also accommodates any control mechanism incorporated like pitch
control mechanism, and yaw control mechanism to orient the rotor
towards wind, the latter is mounted on the top of the supporting
structure on suitable bearings

III. Transmissions
By varying the of the rotor blades about 40-50 revolution per minute, the rate
of rotation of large wind turbine generator can be controlled. For the optimum
generator output it is required to have much greater to have much greater rates
of rotation, such as 1800 rpm, which can be obtained greatly increasing the low
rotor rate of turning. Transmission can be done by using mechanical system
involving fixed gears, belts and chains in in single or in combination or hydraulic
system involving fluid pumps and motor. Because of higher efficiency, known
cost and minimum system risk fixed ratio gears are recommended for top
mounted equipment. For bottom equipment, transmission costs are reduced
substantially by using large diameter bearing with ring gear placed on the hub to
serve as a transmission to increase rotor speed to generator speed. Such a
combination provides a high degree of design flexibility as well as potential
savings.
IV. Generator
At its most basic, a generator is a pretty simple device. It uses the properties
of electromagnetic induction to produce electrical voltage - a difference in
electrical charge. Voltage is essentially electrical pressure - it is the force that
moves electricity, or electrical current, from one point to another. So generating
voltage is in effect generating current. A simple generator consists of magnets
and a conductor. The conductor is typically a coiled wire. Inside the generator,
the shaft connects to an assembly of permanent magnets that surrounds the coil
of wire. In electromagnetic induction, if you have a conductor surrounded by
magnets, and one of those parts is rotating relative to the other, it induces voltage
in the conductor. When the rotor spins the shaft, the shaft spins the assembly of
magnets, generating voltage in the coil of wire. That voltage drives electrical
current (typically alternating current, or AC power) out through power lines for
distribution.
V. Controls:
It perform following functions:

a) Yaw control by orientation the rotor in the direction of the wind.
b) Pitch control of the blades to produce required power.
c) Power generator output monitoring by data computing and data
storage.
d) Maintenance mode.
e) Emergency Power.
f) Emergency shutdown control owing to malfuction or very high winds.
g) Start-up and out-in of the equipment.
Control systems have many combinations possible and may involve the following
components:
i. Sensor- mechanical, electrical or pneumatic;
ii. Decision elements- relays, logic gates, analog circuits,
microprocessors or a mechanical unit.
iii. Actuators- hydraulic, pneumatic or electric
VI. Towers
Four types of supporting tower can be considered for use:
a) The pole tower
b) The reinforced concrete tower
c) The truss tower and
d) The built up shell-tube tower
ADVANTAGES OF WIND POWER
1. The wind blows day and night, which allows windmills to produce
electricity throughout the day (Faster during the day).
2. Wind turbines take less space than average power station.

3. Up to 95 percent of land used for wind farms can also be used for
agriculture purpose.
4. Wind energy is a domestic, renewable source of energy that generates no
pollution and has little environmental impact.
5. We can use WT to generate electricity in remote location such as
mountains and remote countryside.
DISADVANTAGES OF WIND POWER
1. Not reliable, because in many areas its strength is too low to support wind
turbine.
2. Sound from Wind Turbines produces noise pollution from commercial
wind turbines is large.
3. Birds often collide with Turbine blades.
4. Wind turbine construction can be very expensive and costly to surround
wild Life during the build process.
5. Some birds even nest on cages on Wind Towers.
6. Present systems are neither maintenance free nor practically reliable.
Projects in India
India's Largest Wind power production facilities (10MW and greater)
Power Plant Producer Location State
Total
Capacity
(MW)
Cape Comorin
Aban Loyd Chiles
Offshore Ltd.
Kanyakumari Tamil Nadu 33

Total
Capacity
(MW)
Chennai Mohan
Mohan Breweries &
Distilleries Ltd.
Chennai Tamil Nadu 15
Gudimangalam
Gudimangalam Wind
Farm
Gudimangala
m
Tamil Nadu 21
Hyderabad
APSRTC
Andhra Pradesh State
Road Transport Corp.
Hyderabad
Andhra
Pradesh
10
Jamgudrani MP MP Wind farms Ltd. Dewas
Madhya
Pradesh
14
Jogmatti BSES BSES Ltd.
Chitradurga
Dist
Karnataka 14
Kayathar
Subhash
Subhash Ltd. Kayathar Tamil Nadu 30
Kethanur Wind
Farm
Kethanur Wind Farm Kethanur Tamil Nadu 11
Lamda Danida Danida India Ltd. Lamda Gujarat 15
Muppandal
Madras
Madras Cements Ltd. Muppandal Tamil Nadu 10
Muppandal
Wind
Muppandal Wind
Farm
Muppandal Tamil Nadu 22

Total
Capacity
(MW)
Perungudi
Newam
Newam Power
Company Ltd.
Perungudi Tamil Nadu 12
CONCLUSION
Wind energy is also a renewable and pollution-free energy which can help us
to reduce the emissions of greenhouse gases. I believe that wind energy can
become an important asset to solve climate change and global warming issues in
the future. It will also reduce the electricity bill for household operations.

POWER TRANSMISSION AND DISTRIBUTION
Concept of Power transmission and distribution
Electric power is commonly generated at 11kV in generating stations in
India. While in some cases generating voltages might be higher or lower.

1. Generating machines, to be used in power systems, are available
between 6kV to 25kV from some big manufacturers.
2. This generating voltage is then stepped upto 132kV, 220 kV, 400kVor
765kV etc. Stepping up to a certain voltage level depends on the
distance at which power is to be transmitted. Longer the distance,
higher will be the voltage level. Stepping up of the voltage is to reduce
the I2R losses in transmitting power. When voltage is stepped up, the
current reduces by a reliable amount so that the power remains
constant, and hence power loss also reduces. This stage is called
primary transmission.
3. The voltage is stepped down at a receiving station to 33kV or 66kV.
Secondary transmission lines emerge from this receiving station to
connect substation located near load centers (cities etc.).
4. The voltage is further stepped down again to 11kV at a substation.
Large industrial consumers can be supplied at 11kV directly from
these substations. This stage is called primary distribution.
5. Feeders are either overhead lines or underground cables which carry
power close to the load points up to a couple of kilometers. Finally, the
voltage is stepped down to 415V by a pole- mounted distribution
transformer and is delivered to the distributors. End consumers are
suppliedthrough a service mains line from distributors. The secondary
distribution system consists of feeders, distributors and service mains.

DC CIRCUITS
Electric Current is an interconnection of the various elements such as a
voltage source, a current source, resistors, inductors and capacitors. The
performance of any electrical device or machine is always studied by drawing its
electrical equivalent circuit.
Two types of currents may flow in an electric circuit (i) Direct Current
(DC) and (ii) Alternating Current (AC)
DC Circuits
Direct Current (DC) always remains
constant and does not vary with time.
The flow of direct current characterizes
flow of electric charge in one particular
direction. DC circuit consists of
constant voltage sources, constant
current sources and their
interconnection with resistances only.
Elements of an Electric Circuit
An electric circuit consists of two types of elements (i) Active elements or
sources and (ii) Passive elements or sinks.
Sources are the elements of a circuit which possess energy of their own
and can impart it to other elements of the circuit. There are two types of sources
(i) Voltage source and (ii) Current source.
An ideal voltage source is one, whose
terminal voltage remains constant,
irrespective of the current delivered by
it to the load.
An ideal current source delivers a
constant current to the circuit,
irrespective of the load connected to its
terminals.
Practical sources are never ideal, as they possess internal resistance r.

A practical current source is also assumed to deliver a constant current,
irrespective of the load connected to its terminals.
The passive elements of an electric circuit does not possess energy of their
own. They receive energy from the sources. The passive elements are the
resistance, the inductance and the capacitance. When current is passed through
a resistance, it consumes energy and heat is produced. A pure capacitance or
pure inductance does not consume energy, but stores it in the form of
electrostatic and electromagnetic fields respectively.
Resistance (R)
Resistance is the property of a conductor by virtue of which, it opposes or
limits the flow of current through it. The unit of resistance is ohm and is
represented by Ω.
The resistance of a conductor is directly proportional to its length and
inversely proportional to its area of cross section.
𝑅 𝛼
𝑙
𝐴
𝑅 = 𝜌
𝑙
𝐴
where, ρ is a constant, known as the specific resistance or resistivity of the
material. The unit of resistivity is ohm-metre (Ω-m).
The Electric Current
The rate at which the electrical charge is transferred across a point in a
conductor is known as the current flowing through the conductor.
𝑖 =
𝑑𝑞
𝑑𝑡
or 𝐼 =
𝑞
𝑡
The unit of current is ampere (A).
Ampere (A)
One ampere of current is defined as that current, which, when flowing
through a resistance of one ohm, causes a potential difference of one volt across
it.

One ampere of current may also be defined as the current flowing through
a conductor, when a charge of one coulomb crosses across a point in the
conductor in one second.
One coulomb of charge is equal to the charge of 6.242X1018 electrons.
Electric Potential
The electric potential always refers to a point in a charged conductor. The
electric potential at any point in a charged conductor is defined as the work done
to bring a unit positive charge from infinity to that point. The unit of electric
potential is volt.
Potential Difference
The potential difference between any two points of a charged conductor is
the amount of work done to bring a unit positive charge from the point of lower
potential to the point of higher potential. The unit of potential difference is volt.
The potential difference is also referred as the voltage between the two points of a
conductor.
Volt (V)
One volt is defined as the potential difference across a resistance of one
ohm, through which, a current of one ampere is flowing.
EMF of a Source (E)
EMF of a source is the voltage available across its terminals.
The unit of EMF is also volts.
Ohm’s Law
The temperature remaining constant, the current flowing through any
conductor is directly proportional to the potential difference between the two
ends of the conductor.
𝐼 𝛼 𝑉, when temperature is constant
i.e., 𝐼 =
𝑉
𝑅
where, R is a constant, known as resistance of the conductor.
Ohm’s law can be applied for AC and DC circuits.
Limitations of Ohm’s Law
 Ohm’s law does not hold good for non-metallic conductors. The law
governing the V-I relation for them is given by
V = KIm

where, K and m are constants.
 Ohm’s law does not hold good for non-linear devices such as zener diodes,
voltage regulators etc.
 Ohm’s law does not hold good for arc lamps because of the non-linear
characteristics of the arc produced.
Power (P)
Power is defined as the rate at which the work is done. Its unit is watt (W).
𝑃 = 𝑉𝐼 =
𝑉2
𝑅
= 𝐼2
𝑅
Energy
Energy is the capacity to do the work. It is equal to the total work done in a
particular time. Its unit is watt-sec.
𝑊 = 𝑉𝐼𝑡 =
𝑉2
𝑅
𝑡 = 𝐼2
𝑅𝑡
The practical unit of energy is kilowatt hour (kWh).
Resistances in Series
When two or more number of resistances are connected in series end to
end, so that the current flowing through all the elements are same.
Consider three resistances R1 , R2 and R3 which are connected in series
across a supply voltage of ‘V’ volts.
Let V1 , V2 and V3 be the voltage drops across R1 , R2 and R3.
I = Current flowing in the circuit.
According to Ohm’s law, V=IR
In series circuit, there is only one path for the flow of current, so the
current is same in series circuit.
The voltage drops across R1 , R2 and R3 is
V1 = IR1 ; V2 = IR2 ; V3 = IR3
Total voltage applied = Sum of voltage drop across each resistance
V = V1 + V2 + V3

IR = IR1 + IR2 + IR3
IR = I (R1 + R2 + R3)
R = R1 + R2 + R3
Voltage Divider Rule
Total Resistance = R = R1+ R2
2
1 R
R
V
R
V
I
+
=
= ---- (1)
From Ohm’s law, V1 = IR1 ; V2 = IR2
Substituting equation (1) into above equations,
2
1
1
1
R
R
VR
V
+
= ;
2
1
2
2
R
R
VR
V
+
=
Parallel Circuit or Resistances connected in parallel
If two or more number of resistances are joined such that one end of each
resistance is connected to one common point while other ends of the resistance to
another common point, so that the current flowing through each resistance is
different and the voltage across all the resistances is same, the resistances are
then said to be in parallel.
Consider three resistances R1 , R2and R3 which are connected in parallel
across a supply of ‘V’ volts.
Let I1 , I2 and I3 be the currents flowing through R1 , R2and R3 .
I is the total current flowing through the circuit in A.
According to Ohm’s law, V = IR
R
V
I =
where, R is the equivalent or the total resistance of the combination.
In parallel circuits, the voltage across all the resistance is same but current
is different.

1
1
R
V
I = ;
2
2
R
V
I = ;
3
3
R
V
I =
I = I1 + I2 + I3
Substituting for I, I1 , I2 and I3 from the above equations,
3
2
1 R
V
R
V
R
V
R
V
+
+
=








+
+
=
3
2
1
1
1
1
R
R
R
V
R
V
3
2
1
1
1
1
1
R
R
R
R
+
+
=
Division of Currents in parallel branch circuits
Let I1 = Current flowing through the resistance R1 in A
I2 = Current flowing through the resistance R2 in A
V1 = Voltage across resistance R1 in V
V2 = Voltage across resistance R2 in V
V = Voltage supply to the circuit in V
Equivalent resistance is given by,
2
1
1
1
1
R
R
R
+
=
2
1
2
1
1
R
R
R
R
R
+
=
2
1
2
1
R
R
R
R
R
+
= ---- (1)
As the circuit is in parallel, voltage are same, V = V1 = V2
IR = I1R1 = I2R2 ---- (2)
From equation (1),
2
2
1
1
2
1
2
1
R
I
R
I
R
R
R
R
I =
=
+
1
1
2
1
2
1
R
I
R
R
R
R
I =
+
2
1
2
1
R
R
R
I
I
+
= ---- (3)
From equation (2),
IR = I2R2

2
2
2
1
2
1
R
I
R
R
R
R
I =
+ 







+
=
2
1
2
1
R
R
R
R
R

2
1
1
2
R
R
R
I
I
+
= ---- (4)
Problem: Find equivalent resistance of the circuit shown in figure.
Solution:
Resistances between B & C are in parallel to each other, so
1
𝑅𝐵𝐶
=
1
5
+
1
2
+
1
4
=
19
20
𝑅𝐵𝐶 =
20
19
Ω
Resistances between C & D are in parallel to each other, so
1
𝑅𝐶𝐷
=
1
4
+
1
8
=
3
8
𝑅𝐶𝐷 =
8
3
Ω
Now, the resistances RBC, RCD and RDE are in series to each other, so
RBC + RCD + RDE =
20
19
+
8
3
+ 1.35 = 5.07Ω
Equivalent resistance of the circuit, Req = RAE
= 0.397Ω
Req = RAE = 2.51Ω
Problem: Three resistance of 1Ω, 4Ω and 6Ω are connected in parallel to each
other. This parallel combination is connected in series with 1.93Ω. Calculate the
equivalent resistance of the circuit as well as the voltage applied when a current
of 4.2A flows into the circuit.

Solution:
Resistances 1Ω, 4Ω and 6Ω are connected in parallel so, the resistance of this
parallel combination,
1
𝑅𝑝
=
1
1
+
1
4
+
1
6
=
17
12
𝑅𝑝 =
12
17
Ω
Equivalent resistance of
the circuit, Req = Rp + 1.93
Req = 2.63Ω
From Ohm’s Law, V = IR
So, V1 = IReq = 4.2 X 2.63
V1 = 11.046V
Problem: In the parallel arrangement of resistors,
current flowing in 8Ω resistor is 2.5A. Find
(i) current in other resistors (ii) resistance X
(iii) equivalent resistance
Solution:
V1 = IR (from Ohm’s Law)
V1 = 2.5 X 8 = 20V
(i) I40Ω = 20/40 = 0.5A
I25Ω = 20/25 = 0.8A
Applying KCL, we have
I = I8Ω + IX + I40Ω + I25Ω
4 = 2.5 + IX + 0.5 + 0.8
4 = IX + 3.8
IX = 4 – 3.8 = 0.2A

(ii) V = IR (from Ohm’s Law)
20 = 0.2 X
X = 20/0.2 = 100Ω
(iii) Equivalent resistance,
1
𝑅𝑒𝑞
=
1
8
+
1
100
+
1
40
+
1
25
=
1
5
Req = 5Ω
Problem: Find the value of R so that a current of 250mA flows into the circuit
from source.
Solution: V = IR
𝑅𝑒𝑞 =
𝑉
𝐼
=
5
250𝑚
Req = 20Ω
Now, the equivalent resistance is calculated and equating this to total resistance
combination of the circuit, we have

�40 +
40𝑅
40 + 𝑅
� 30
40 +
40𝑅
40 + 𝑅
+ 30
= 20
�
40(40 + 𝑅) + 40𝑅
40 + 𝑅 � 30
40𝑅
40 + 𝑅
+ 70
= 20
(40(40 + 𝑅) + 40𝑅)30
40𝑅 + 70(40 + 𝑅)
= 20
(1600 + 40𝑅 + 40𝑅)30
40𝑅 + 2800 + 70𝑅)
= 20
48000+2400R = 2200R+56000
2400R-2200R=56000-48000
200R=8000
R=40Ω
Problem: The total power consumed by the circuit is 16W. Find the value of R
and the total current.
Solution:
Power, P = VI
Then, current, I = P/V = 16/8 = 2A
𝑅𝑒𝑞 = �
4𝑅
4 + 𝑅
� + �
2𝑋8
2 + 8
�
=
4𝑅
4 + 𝑅
+ 1.6
From Ohm’s Law, V = IR, then
R = V/I = 8/2 = 4Ω
𝑅𝑒𝑞 =
4𝑅
4 + 𝑅
+ 1.6
4 =
4𝑅
4 + 𝑅
+ 1.6
4𝑅
4 + 𝑅
= 2.4
4R=2.4(4+R)
4R=9.6+2.4R
4R-2.4R=9.6
1.6R=9.6

R=6Ω
Kirchhoff’s Current Law
Statement: The algebraic sum of all the currents meeting at any junction of an
electric circuit is zero i.e., ΣI = 0
The figure shows the junction A of an electric circuit at which four
currents I1, I2, I3 and I4 meet. All the currents flowing towards the junction are
taken as positive and all the currents flowing away from the junction are taken as
negative. Then, according to Kirchhoff’s current law,
I1 + I2 – I3 – I4 = 0 or I1 + I2 = I3 + I4
From the above equation, Kirchhoff’s current law can also be stated as “At
any junction of an electric circuit, the sum of all the currents entering the
junction is equal to the sum of all the currents leaving the junction.”
Kirchhoff’s Voltage Law
Statement: In any closed electrical circuit, the algebraic sum of all the emfs and
the resistive drops is equal to zero i.e., ΣE + ΣIR = 0
All the voltage rises are taken as positive and all the voltage drops are taken
as negative.
A battery of emf E volts connected between two points a and b, which can
be traced either from a to b or from b to a. When it is traced from a to b, the

battery is traced from negative terminal to positive terminal. It is a voltage rise.
Hence, emf is positive, i.e., E is positive.
When the battery is traced from b to a, it is traced positive terminal to
negative terminal. It is a voltage fall. Hence, emf is negative, i.e., E is negative.
The directions of
current I flowing in
the various branches
of the circuit are
arbitrarily assumed.
For the closed loop in
the circuit using
Kirchhoff’s voltage
law, the equations are
E1 – IR1 – IR2 = 0
KVL (Mesh Analysis)
Equations are given by
Loop 1
E1 – I1R1 – R2(I1 – I2) = 0
Loop 2
-I2R3 – I2R4 – R2(I2 – I1) = 0

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