CHAPTER 11
Electrical engineering is concerned with the basic forms of energy that run our world.
Gas
Hydro
Turbine
Geothermal
Wind
Photovoltaics
Electrical Engineers deal with the distribution of these energies from their sources to our daily usage. (Homes, Factories, Offices, Hospitals, Schools,…etc….)
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Installation and Maintenance
Integrated circuits
Embedded systems
Electronic equipments etc have also provided large scale placements for engineers with this specialization.
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Knowledge of
Computer Hardware
Networking equipments
Communication systems
Enables Electrical Engineering graduates help them to annex an edge in the IT job market
The skills and understanding developed in the course enable them to be preferred, as software professionals by IT companies.
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Electrical engineering industry encompasses a wide area of activities from
lighting to mobile communications and
that is why this industry has a huge capital earning potentiality, which can strengthen the economy of a country.
Electrical engineering industry can reduce the growing world economies from the vulnerability to energy shortages.
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Clean electrical energy can be an alternative source of power.
But we normally acquire from hydrocarbons like
Coal and
Petroleum products etc.. and this way it is gradually leading to Global Warming, in turn affecting everything around us.
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(hydro-, thermo-, nuclear-power, or from coal and
petroleum products).
Bulk of the energy is consumed at the household
Woodfuel, forms of biomass, biogas, micro-hydro,
solar and wind power, mostly at a small scale.
Energy is primarily used for cooking food
Where does Electricity come from?
Energy consumption per capita in kWh
Canada USA Australia Japan France Germany United Kingdom Russia Italy India 17179 13338 11126 8076 7689 7030 6206 5642 5644 631
POWER CONSUMPTION FOR HOUSEHOLD
NEED OF THE HOUR
Renewable Sources of Energy
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To world energy security
Conceptually, one can define three generations of renewable technologies, reaching back more than 100 years.
First-generation technologies emerged from the industrial revolution at the end of the 19th century that includes
Hydropower
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Solar heating systems are a well known second-generation technology.
Generally consisting of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage and a reservoir or tank for heat storage and subsequent use.
The systems may be used to heat
domestic hot water
most photovoltaic modules provided remote-area power supply,
But, from around 1995, industry efforts have focused increasingly on developing building
integrated photovoltaics and
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Arid regions receive plentiful Solar radiation, regions like Rajasthan, Gujarat and Haryana receive sunlight in plenty.
Thus the Potential availability - 20 MW/km2 (source IREDA)
IREDA is planning to electrify 18,000 villages by year 2012 mainly through Solar PV systems
Targets have been set for the large scale utilization of PV technology by different sectors within the next five years
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No Sulfur Dioxide (SO2), Nitrous Oxide (NOx), or Mercury Emissions
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Wind, for now, is the renewable energy resource/technology of choice
“Free” resource
Replacement of a “dirty” energy source (coal) and,
No emissions associated with its use
Can be utilized on underutilized land or on lands currently in commodity crop production
(“harvest” on the surface and “harvest” above the surface)
Will primarily be used for electricity generation for immediate end-use or as a “driver” for hydrogen production
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No cooling water
No water pollution
Small (10 kW)
Intermediate
Central Station Wind Farms
Provide wholesale bulk power
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increases rapidly at lower heights
but less rapidly at higher heights.
At about 2000 metres from the ground, the change in the wind speed becomes zero.
This variation of wind speed with height depends upon
terrain roughness and
Power in the wind
Kinetic energy in the wind owing across a wind turbine is used to derive electrical energy from the wind.
The Power in the wind turbine “P” is given by
P= (1/2)ρAV3
Where “ρ”=air density and at standard temperature (25C)
and pressure, is about 1.22 kg/ m3
“V” =wind velocity in m/s.
“A”=Swept area.
ENERGY SAVING TIPS
Take advantage of daylight by using
light-colored loose-weave curtains on your windows to allow daylight to penetrate the room.
Also, decorate with lighter colors that reflect daylight.
De-dust lighting fixtures to maintain illumination.
Compact fluorescent bulbs are four times more energy efficient than incandescent bulbs which provides the same lighting.
Do not switch on the power when TV and Audio Systems are not in use.
i.e. idle operation leads to an energy loss of 10 watts/device.
If your computer must be left on,
turn off the monitor;
this device alone uses more than half the system's energy.
Battery chargers, such as those for
laptops,
cell phones and
digital cameras, draw power whenever they are plugged in and are very inefficient.
Pull the plug and save.
Screen savers save computer screens, not energy.
Start-ups and shutdowns do not use any extra energy, nor are they hard on your computer components.
In fact, shutting computers down when you are finished using them actually reduces system wear – and saves energy
In washing machines use timer facility to save energy.
Plant trees or shrubs to shade
air-conditioning units but not to block the airflow.
A unit operating in the shade uses as much as 10% less electricity than the same one operating in the sun
Electrical Hazards
Shocks
Electric Shock causes an involuntary grip which prolongs the period of contact
More the period of contact, more the damage
Passage of current through the heart,
stops the blood supply to the brain,
resulting in loss of consciousness and
termination of breathing
When a person standing at a height receives an electrical shock, it is most likely that he will fall.
Personal sensitivity to electrical shock varies from person to person
Burns
Whenever an electrical flash appears, and if a part of a body comes within flashing distance, burns can be caused.
Burns may be caused by short circuits as well, because a short circuit could create an electrical fire`
Preventive Measures
Allow only a qualified person to attend to your electrical repairs
Service your electrical equipment at frequent intervals through a competent electrician
In case of a short circuit or a fire,
Switch off the mains instantly
Make sure that you have easy access to switch off the supply source quickly, in case of an emergency
Make sure your extension cords are free from cuts, improper insulation, or joints.
Ensure pins of your plugs are tight and not loose
Use switches of the correct current rating and preferably with indicators to indicate whether the switch is ON/OFF.
Use appliances with 3 pin plugs and connect them to 3 pin sockets
Do not overload electrical outlets or use extension cords in place of additional outlets
Provide proper earthing for the building/house
IMPACT OF ELECTRICAL ENGINEERING OVER ENVIRONMENT
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Large power sources can affect their surroundings through impacts such as
air pollution,
China and India use the traditional pulverized coal combustion technology.
As a result, they have to contend with gaseous emissions including
Carbon dioxide (CO2), carbon monoxide (CO) etc.,
(Green house gases)
the associated problems of mining accidents and
land degradation are serious.
large hydroelectric plants are not impact-free.
Large dams can cause submergence of human settlements and natural forests,
adversely affecting or even destroying people’s livelihoods,
particularly traditional lifestyles and
disposal of radioactive spent fuel must also be contended with.
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“SAVE ENERGY “ “GO GREEN”