This document assigns students to groups for an electrical engineering project and provides background information on electricity. It discusses how electricity is generated at power stations and transmitted through transformers, transmission lines supported by pylons, and distribution lines to homes. Precautions for electric safety are also outlined. The document is submitted by the electrical engineering department of Hormuud University on March 5, 2016 for assignments.

1. Hormuud University

2. FACULTY OF ENGINEERING
DEPARTMENT: ELECTRICAL ENGINEERING
DATE OF SUBMISSION: 05/03/2016
ASSIGNMENTS:
GROUP "A“
1. Ali abdi mohamed ID 212
2. Mohamed omar aadam ID 410
3. Hassan mahdi nur ID 405
4. Saa'id mohamud mohamed ID 382
5. mohamed abdullahi cumar ID 407
GROUP "B"
1. Abdulkadir Hussein Hassan ID 339
2. Abdifitax dahir siyaad ID 395
3. Abdihafid Ahmed abdullahi ID 396
4. Abdiwali mohamed nur ID 403
5. Abdinuur mohamud abdullahi ID 399
GROUP "C"
1. Abdiwali mohamed salaad ID 338
2.Abdihaliim murshid mohamed ID 397
3. Mahdi mohamud Hussein ID 406
4. Abdirahman mohamed sheikh khaliif ID 400

3. How to reach electricity to our homes?
What is Electricity?
The flow of electrons from atom to atom in a conductor
Electricity is based on a theory- an “unseen” force because the energy itself cannot be seen,
heard, touched, or smelled.
Electricity is widely used for providing power to buildings, electric devices, and even some
automobiles. A number of individuals are responsible for the development of electricity,
but the most notable one is Benjamin Franklin.
Requirements
 Power generator
 Transformer
 Transmission
 Distribute lines
POWER GENERATOR
In electricity generation, a generator is a device that converts mechanical energy to electrical
energy for use in an external circuit.
The reverse conversion of electrical energy into mechanical energy is done by an electric
motor, and motors and generators have many similarities.

4. Cont…
 Power station: Electricity we use at homes, in our
factories, is supplied from a power station.
 Electric cell : is a source of electricity.
An electric cell produces a small amount of electricity from
chemicals stored inside it.
When the chemicals in the electric cells are used up, the
electric cells stop producing electricity.
Fuses are devices used to protect the electrical circuit from
too much current flow
A fuse is designed to open the circuit when the current
reaches a predetermined level.

5. Transformer
 A transformer is a static machine used for transforming power
from one circuit to another without changing frequency.
 A transformer is a device which transfers electrical energy
(power) from one voltage level to another voltage level.
 A transformer is a static device and all currents and voltages
are AC.
 Transformers can be categorized in different ways, depending
upon their purpose, use, construction etc.
 Step Up Transformer & Step Down Transformer -
Generally used for stepping up and down the voltage level of
power in transmission and distribution power network.

6. Transmission
• Transmission lines carry electricity from the power
plant to locations that can be far away.
While traveling, electricity loses voltage or strength, in
the form of heat. Transformers help the voltage to
make up for losses.
The high-power transmission lines move from tower
to tower until they reach a substation
in your area.
The electricity on these lines typically runs at
115,000, 230,000 or 500,000 volts.

7. Distribution lines
Distribution lines carry the electricity from a substation
to your home or business. They may
be overhead (as shown in the above diagram) or
underground.
Electricity traveling on distribution lines is at 14,270
volts.
ALWAYS STAY AWAY FROM POWER LINES
ESPECIALLY WHEN THEY ARE ON THE GROUND!
Transformers are often seen on distribution lines as well.
They look a bit like a big can way up on a power pole.

8. Cont…………

9. Cont…

10. Sources of energy/electricity
1: Hydroelectric power station
2: Geothermal power station
3: Windmill power station
4: Nuclear power station

11. Electrical power transmission
National grid system(NGS)
The electrical energy generated at a power station is
delivered to the consumers through cables.
the process of distributing power to the consumers is
called electrical power transmission. Electrical power is
distributed to consumers all over the country through a
national grid system, which consists of a network of
transmission cables carried over through structures
called pylons. In most power generating stations , the
voltage generated is about 25000volts and the current
is about 100Aal energy.

12. Cont…
the electrical power generated at a power station is
not delivered to the consumers at this raw voltage or
current. Instead of transmitting power directly to the
consumers , a step-up or build-up transformer is
used at the station . in this transformer, the voltage
generated is increased to 220KVor 500KV. Before
reaching the consumers , the voltage is reduced to
240V using step-down transformer . so that
electrical energy used in industries and houses is
converted into either light , heat or mechanic.

13. RENEWABLE AND
NON-RENEWABLE ENERGY
RENEWABLE ENERGY include :
 Solar
 Water
 wind
NON-RENEWABLE ENERGY include:
 Oil
 Natural gas
 Coal

14. Electrical safety precautions
 Electric shock
When working on electric circuit ,there is the
possibility of receiving an electric shock. An electric
shock can cause you to fall down . it may cause
severe, rigid contractions of the muscles, which in
turn may result in fractures , dislocation , and loss
of consciousness. The respiratory system may be
paralyzed and the heart may beat irregularly or
even stop beating altogether. Electrical burns may
be present on the skin and extend into deeper tissue .

15. Cont…
high current may cause death of tissues between the
entry and exit point of the current . electric shock can
cause muscle spasms(involuntary muscle contraction
or tetanus),weakness , shallow breathing , rapid
pulse , severe burns, unconsciousness, or death

16. Cont…
 Electric shock is an injury caused by an electrical
current passing through the body.
Precautions
Working with electricity can be dangerous unless
you adhere to certain rules .
1: Always make sure that the circuit is actually
dead before you begin working on it
2: Always unplug any appliance or lamp before
repairing it.

17. FACTORS INFLUENCING SEVERITY
The severity of electric shock or the amount of
current which flows on the body depends on
1: Frequency of supply
2: Level of voltage
3: State of the point of contact with the body
4: Duration of exposure
5: Resistance of the body

18. Warm-up???
How do we get electricity to our homes:
Use these words to fill the blanks: ground, power
station , pylons , cables
1: electricity goes from the
______________________ to our home , shops ,
etc
2: It travels along thick wires called
___________________.
3: Metal towers called
_________________________ hold the cables
high above the ____________________.

19. Look these two statements
 Electricity is a great friend but indeed it is enemy.
 Electricity does not respect heroism
Assignments (self assessment)
 Why transmission cables carrying high voltages
are supported high above the ground by pylons?
 if the Ac electricity is continuously fluctuating
/changing direction why don’t you perceive that
fluctuation on your light bulb?

20. END
THANKS ALL
OF YOU FOR
RESPECTING
US!