Generation, Transmission, And Conversion of ElectricityIntroduction to electrical circuits

By: Ali Reda Ali

Electricity, The important thing in the 21th century -that I think-.

One a day, do you think about no electricity?Simply, I would not present this show to you!TVs, Computers, Metro, Cars, ... Etc. The first thing that they want to work is the electricity.The evolution of our life because of electricity.

We want every day to a huge quantity of energy, electricity is almost energy to want and we can convert it –simply- to another form of energy.

But, How do we get the electricity?

4

We can get the electricity energy from

• Coal (The most unfriendly-enviro resource)• Earth (From hot rocks deep inside the Earth)• Water (Generating energy by waves)• Sun (Using solar cells)• Wind (The amount of energy depends on the

amount of wind, using an electricity generator on top of a tall tower).

5

There are two types of energy resources

RenewableEnergy resources

can be replaced or

regenerated and will

never run out (at

least not for a very long time).

Non-renewableEnergy resources will eventually run out – once used they cannot be used again.

6

Energy Resources

First: Generation of ElectricityThe fundamental principles of electricity generation were discovered in 1830s by Michael Faraday.This method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper

between the poles of a magnet.

First: Generation of Electricity Cont.

First: Generation of Electricity Cont.

Almost all electrical power on Earth is generated with a turbine, driven by wind, water, steam or burning gas. The turbine drives a generator. There are many different methods of developing mechanical energy, including heat engines, hydro, wind and tidal power. Most electric generation is driven by heat engines. modern steam turbine (invented by Sir Charles Parsons in 1884) currently generates about 80% of the electric power in the world using a variety of heat sources

Second: Transmission of ElectricityElectricity is generated at power plants and moves through a complex network, or grid, of electricity substations, power lines, and distribution transformers before it reaches consumers. By default, there is a lose in energy generated because of the high length of wires and the temperature in the sands.

Second: Transmission of Electricity Cont.

According to Faraday's Law, since the same magnetic flux passes through both the primary and secondary windings in an ideal transformer, a voltage is induced in each winding, in the secondary winding case, in the primary winding case. The primary EMF is sometimes termed counter EMF. This is in accordance with Lenz's law, which states that induction of EMF always opposes development of any such change in magnetic field.

Second: Transmission of Electricity Cont.

Real transformer energy losses are dominated by winding resistance joule and core losses. Transformers' efficiency tends to improve with increasing transformer capacity. The efficiency of typical distribution transformers is between about 98 and 99 percent.

Finally: Conversion of ElectricityAC current is generated by turbines, but your mobile want to DC current to charge.DC current is generated by semiconductors solar cells, but your fridge or TV wants to AC current to work.How we can convert between them?

AC VS DC!

Alternating current describes the flow of charge that changes direction periodically. As a result, the voltage level also reverses along with the current. AC is used to deliver power to houses, office buildings, etc.

AC VS DC Cont.

Direct current is a bit easier to understand than alternating current. Rather than oscillating back and forth, DC provides a constant voltage or current.

A- AC Input To DC Output

The task of turning AC into DC is called rectification, and the electronic circuit that does the job is called a rectifier. The most common way to convert alternating current into direct current is to use one or more diodes.

A charger 5V circuit

• A bridge rectifier overcomes this limitation by using four diodes instead of two. The diodes are arranged in a diamond pattern so that, on each half phase of the AC sine wave, two of the diodes pass the current to the positive and negative sides of the output, and the other two diodes block current.

A- AC Input To DC Output Cont.

B- DC Input To AC Output

Semiconductors solar cells are source of DC, but we want to use this energy to run AC devices.Inverter, is an electronic device or circuitry that changes DC to (AC).

It is a power amplifier driven by an astable multivibrator. However, rectifier filtering capacitors required are considerably smaller at the higher operating frequency. The two transistor should be mounted on an adequately sized heatsink. The transformer should be rated according to the amount of output power required allowing for conversion efficiency of approximately 60%

B- DC Input To AC Output Cont.

ThanksAli Reda AliTuesday, December 20, 2016