12- Electrical Engineering - Government College University. Electrical... · The Scientiﬁc Ravi...

The Scientific Ravi 2015 Electrical Engineering

Government College University, Lahore. 50

Do you know these facts about Electrical Technology?

Noman GhafoorOld Ravian

The human life today is completely surrounded by electronic devices that run on power. Without power, one can't even imagine how the world would be. Here are some facts and information that will certainly blow your mind.

1. V won't kill you. I will.

2. That there is no use stealing a fan or bulb from the Pakistani trains. They are designed to work at 110 volt supply. The supply in your homes is rated at 220 volts everywhere.

3. Ever wondered what's inside this bead at end of your laptop or mobile charger?

This is called ferrite bead or, more generically, a choke. It's a fancy name for what's basically an electromagnetic wave-bouncer.

If you open this bead, you will not find any complex circuits but only a ferrite cylinder that is magnetic in nature. It is this magnetic quality of the bead that serves the purpose.

So basically, when current passes through any cable, it generates electromagnetic interference (EMI).

Electronic gadgets generally produce EMI during operation. For example, if you connect a camera to your monitor, the camera would produce interference and cause your monitor to flicker without the presence of a ferrite bead. If left unabated, EMI can cause havoc with your computer peripherals.

These ferrite chokes ensure that signals are only sent in the intended directions and no EMI is transmitted between the peripherals. The choke dampens these EMI waves by acting as an EMI blocker. The blocking is most effective when it is near the source of the EMI, that's why you will only find these ferrite beads near the end of the cables.

4. AC and DC shocks will strike you in different manner. The effects of AC (alternating current) depends largely on frequency, low frequency tends to be much more dangerous than high frequency. AC with the same amperage and voltage as DC is more dangerous and provokes worse effects on the human body.

Low f requency AC provokes musc le contraction (tetany) which can induce the "cannot let go" effect by freezing the muscles of the hand. This happens because the flexors of the hand are much stronger than the extensors, so when an external electric estimation is applied the muscles flexors of the hand win. AC has more tendency to induce heart fibrillation while DC makes the heart stand still. That is why defibrillation equipment is DC, which stops the heart and gives a chance to recover.

5. Electrical energy is transmitted at the surface of and outside the conductor, not inside the wire.

6. Did you know that electricity plays a role in the way heart beats?

Electricity causes muscle cells to contract, Electro cardiogram (ECG) used by the medical



professionals, measure the electricity going through heart, as heart beats in a healthy person, the ECG machine displays a line moving across the screen with regular spikes.

7. Your refrigerator uses less power than PlayStation 3.

8. The amount of power needed for google to run a 100 searches is equivalent to burning an incandescent lamp for 28 minutes.

9. Benjamin Franklin did not discover electricity, he just proved lightning is also a form of electricity.

10. Electric fields work similar to gravity whereas gravity always attracts, electric fields can attract or repel.

11. Electricity always tries to find easiest (low resistant) path to ground.

12. Ever wondered why a crow sitting on an electrical transmission line doesn't experience shock?

It is because, the movement of electrons, that is, current, is the ultimate thing which causes shock. It is the electric current that burns tissue, freezes muscles, and fibrillates hearts. Here, the current doesn't pass through the crow.

To know why, you have to understand these things:

a) Electric current flows through the path only when there is a potential difference between the starting and ending points of the path. Electric current doesn't occur by itself. We need voltage (potential difference) across a path. It is just similar to two buckets of water connected by a small pipe. The flow of water is analogical to the flow of electrons, that is, current. It requires a difference in potential for the flow.

b) Electric current flows only when there is a closed path. But here is a closed path. It's crow's left leg, crow's body, crow's right leg and the wire makes it a closed path.

c) How to calculate the voltage drop? The formula for the voltage drop is v=IR, where, I is the current and R is the resistance of the conductor. Generally, the resistance of the transmission line between crow's legs is very negligible. Very close to zero. So, if the voltage at crow's left leg is 11,000 volts, then the voltage at crow's right leg is also 11,000 volts as there is no voltage drop in the line.

So, the potential difference v across the crow's legs= (11,000-11,000) =0, which makes the current not to pass through the crow.

Now let's leave that crow. Let us come to humans. For electrical engineers, those transmission lines always appear in colors like those that appear in the images below.

What happens when you are hanging like this?

You won't get shock, because it requires closed path for the current to flow through you.



What happens when you are hanging like this?

Even though there is a closed path, you won't experience shock because the resistance of the wire between your hands is nearly zero and so as potential difference. Same case like crow.

What happens when this is the case?

You wouldn't be laughing like that troll face. You will get electrocuted because the ground is considered having zero potential. So there is a potential difference between your hand and legs and it is equal to 11,000 volts (11,000 -0).

What happens when this is the case?

Here also you will get electrocuted. The crow

concept doesn't work here.

You are wrong if you think that both lines will be carrying 11,000 volts and the potential difference between your left hand and right hand is 0 as 11,000-11000=0. It's not like that.

You are right if those two lines are carrying same DC voltage. However, it's an imaginary case (DC lines will not be carrying same voltages. If one DC line will be caring 11000V, the other one will be 0 volts.

In this case also you will be dead because of potential difference 11,000 volts (11,000-0). But the transmission lines are of AC. Those three are differed by 120 degrees in phase. At any instant, the voltages of the three lines are not equal.

If the red line is having 11,000 volts at one instant, the yellow line will be carrying some -5500 volts and the blue line will be carrying some -5500 volts, etc. So at this instant you will be electrocuted badly as the voltage difference is 11,000v-(-5500) v= 16,500volts.

For your reference, the voltages will be varying in those three transmission lines like this with respect to time.

Hope You enjoyed the facts.

Solar Roads: The Future of PowerGeneration!

Shehroz AslamAssociate Editor,The Scientific Ravi

The advanced technology is turning the ridiculous imaginations of human thinking into practically efficient applications. In the near future, our vehicles could be running on glass roads. Yes you read right, this idea no more remains unbelievable when the modern ci t ies contain suitable



infrastructures of roads. And the technology required already exists to construct the solar cells within the high traffic routes converting them into a huge power generator. Considering the global energy requirements in this developed era, the humans have to innovate new technological ideas with the growing consumers and economic challenges.

“Technological innovation is indeed important to economic growth and the enhancement of human possibilities”

- Leon Kass

Figure-1 The wide roads provide the required spaces.

Solar roads can change how we power the world. The flat roads in the urban cities can be a great source of renewable energy, decreasing the dependence on fossil fuel. This form of renewable energy can be one of the key factors to the future advanced societies.

Solar Roadways Project

Dreaming the idea of overcoming conventional fossil fuel dependence for energy generation, electrical engineer Scott Brusaw has been working on this fantasy-now-becoming-reality project for some years now. He is exciting many people with the concept of planting photovoltaic panels in all the busy traffic roads and parking lots in US to gain power from sun. Yes, really any surface under the sun. Although, it is one of the forms of glass is used, but it has great tolerance enough to withstand trucks weighting in the range of 250,000 lbs.

Figure-2 The resurfaced roads can generate efficient power.

The project construction involves interlocking tempered glass hexagonal panels that have been studied for traction, load capacity and other influential factors. For harvesting the power from the sun, the photovoltaic panels are constructed and embedded in these panels, turning the wide roads that have never been thought of being more efficient before. The glass used is only a half inch thick, containing layers, and is laminated. The residential houses and businesses are then connected to pavements and parking lots.

"A nationwide system could produce more clean renewable energy than a country uses as a whole," Brusaw predicts.

According to the project research, if every road in the country gets covered, these would produce up to three times of the energy the country uses currently. Solar Roadways has already signed two contracts from the U.S. Federal Highway Administration for research and development of the paving systems, and is increasing funding for more future developments.

The whole idea may be impossible to some people, but this amazing concept has won many nominations and global awards from GE, Google and the IEEE Ace Awards, the World Technology Award, along with his idea presentation at NASA, TEDx, and Google's Solve for X.

Key Advantages

Ÿ The future energy requirements can be met while reducing the increasing carbon emissions from automobiles along with consuming fossil fuel consumption.



Ÿ Since the roads will produce lifetime power, the initial undeniable large investments for reconstructing useful roads will be covered.

Ÿ The solar panel technology is becoming efficient day by day, so the technology in the next few years will become much cheaper making the idea more viable.

Ÿ In America, the project is expected to replace the aging electric grid system, cable TV, provide high speed internet and telephone connected anywhere with the road.

Future scope and innovation:

The solar power project can be a profitable investment considering the power challenges of the future. The fundamental concept is based on the photovoltaic panels constructed on the surface of heavy traffic routes to produce energy. One of the main concern is regarding the massive initial investment required for resurfacing huge number of roads but recent reduction in solar technology's cost will provide more efficient and cheaper panels.

In the advanced world where researchers are warning us about the more fuel and power challenges in the near future, without such technological innovations the human life has immense problems ahead. Although, there are many forms of renewable energy, but this concept will maximize the wide roads and spaces already available. However, the energy crisis is a global complication and innovating more technological revolutions is the way to go.

Student Satellites

Armughan ShaqueOld Ravian

Space has always been a subject of fascination for human beings. From beginning, man has tried to explore and unravel the mysteries of universe. There are many scientists and philosophers in ancient times who presented their theories and understandings of this universe such as Aristotle, Ptolemy, Copernicus and many others. Similarly, in modern times, there are people like Stephen Hawking who presented Big Bang Theory to describe the beginning of this universe.

With the improvement in technology, new methodologies have been developed to study objects beyond the frontiers of our planet. One of

the important inventions in this field is the development of Satellites for various purposes. Besides traditional satellites, Students Satellite is a relatively new concept. The idea came into existence when in 1999 California Polytechnic State University and Stanford University developed the CubeSat specifications. There are two main types of Student Satellites: Pico Satellites and Nano Satellites.

A Nano satellite is an artificial satellite with mass between 1 kg and 10 kg whereas a Pico satellite has a less than 1 kg. The basic purpose for the development of Pico and Nano satellites is that large traditional satellite missions can cost in millions; therefore if we want to test some new design, we can use Pico and Nano satellites which are relatively cheaper and their mission time is also less, thus providing us much flexibility.

The development of a Nano satellite mission is significantly different as compared to that of a conventional satellite because with the decrease in size and dimensions, the development costs are reduced as well. Also the time span of mission is also less than that of a large satellite i.e. they remain in space just for three to five months.

There are some limitations that are faced while designing these satellites. First of all, the power capacity is limited. Secondly, there are length and weight constraints as well. Still, Nano satellites provide us with many advantages as well. The budget is low, modifications are easy, design can be simple and power-efficient and we can provide redundancy as well.

Figure -3 A Nano satellite NCUBE 2, designed in Norway



Nano satellites can be used for various purposes but here we focus on communication satellites. These satellites have following main sections:Ÿ Power System UnitŸ Telemetry Tracking and Control UnitŸ Data Handling UnitŸ Altitude Determination and ControlŸ System

Ÿ Payload

Power System Unit further comprises of two parts: Power Conditioning Unit and Power Distribution Unit. Power Conditioning Unit takes unregulated input from Solar Array and sends regulated output to battery and to load. It also regulates charging and discharging of battery through Maximum Power Point Tracking. Power Distribution Unit distributes power to different sections of load.

Telemetry Tracking and Control Unit provides communication between Satellite and Earth. This module is very important because loss of communication is a catastrophe for mission. It receives commands form ground station and transmits them back.

Data Handling Unit provides memory for software and data storage. It issues commands as well in order to work according to the desired task.

Altitude Determination and Control System determines the orientation of Satellite and provides it stability. Although, most of these satellites are developed by universities, several companies such as Boeing have also taken interest in their development. At present, many universities around the world are working on building their own Student Satellites and this work will also continue in future. It will provide a good chance for students to develop their skills and interest in the field of satellites and space.

VANET (Vehicular Ad hoc Network)

Hassan FarazOld Ravian

With the globalization and advancement in the technological sectors, man has devised methods of improving the lifestyle and found out new avenues to support the actions and proceedings. Human beings are constantly keeping themselves connected with each other on the go by creating new and innovative methods to support communication with each other and equip them with facilities that

have wide range of advantages. Sometime back when people rode the vehicles, they were out of contact with the world; then after taking this problem into consideration and providing facilities to the vehicle user, Global Positioning System (GPS) was started to be installed in cars and thus providing the location of the car to an external source used for tracking the location of the vehicle; also the driver was given the advantage to navigate easily and efficiently with the support given by the GPS.

With the passage of time and advancement in the technological sector, the problems with the trafficking of the vehicles were started to be solved by the scientists and experts who were concerned about the safety, other issues and had an urge to provide ease to the human beings. The number of accidents occurring on the roads started to increase thus making it a huge number and a thought that required consideration.

A Vehicular Communication System (VCS) was devised considering different facts in mind which later became the applications of this VCS. Every vehicle was supposed to be a node of a network which communicates with each other and this network was ad hoc. By Ad hoc we mean a network that requires little or no planning to be established. Every vehicle was given the capability to communicate with other vehicles and with a server thus getting the necessary information and communicating with each other. All this communication was made possible in order to overcome the needs of the vehicular trafficking. The method devised was known as Vehicular Ad hoc Network also known as VANET.

There are basic two types of vehicular communication, namely,

Ÿ Ve h i c l e t o Ve h i c l e C o m m u n i c a t i o n (V2V)

Ÿ Vehicle to Infrastructure Communication (V2I)

The equipment or the components required for the vehicular communication can be given as follows:

Ÿ Global Positioning System (GPS)

Ÿ Event Data Recorder (EDR)

Ÿ Front and Rear Radar in the car

Ÿ Human-Machine Interaction

Ÿ On-Board Unit (OBU)

Ÿ Road Side Unit (RSU)

Ÿ Electronic License Plate (ELP)

All the modern vehicles contain some components which are now a vital and essential part of that vehicle. They include a GPS, an EDR which is Event Data Recorder and contains all the necessary information such as the speed etc. in it and plays the same role as the black box of an aircraft, a computing machinery that basically runs the vehicle, a human-machine interaction or communication setup that is used by the user in order to communicate with the vehicle, rear and front radars for the effective communication and positioning, an On- Board Unit (OBU) which is used to communicate in a VANET.

The communication in a VANET is done from vehicle to vehicle in which the vehicles communicate with each other thus transferring information to each other. And the vehicles communicate with the infrastructure which is the representative of the server on the road and is known as Road Side Unit (RSU), this unit provides information to the vehicle in time of need. The RSU are connected with the servers which provide Location Based tacking of the vehicle which is just like keeping an eye on all the nodes in a network and the traffic monitoring to save the vehicles from any mishap.

For the efficient communication between the vehicles and with the infrastructure the Electronic License Plate (ELP) and Electronic Chassis Number is used to improve the logging and connecting process. I t a lso helps in the identification of the vehicle. The Dedicated Short Range Communication (DSRC) is done by the identification of the vehicle by the electronic license plate and communicating with the required vehicle. All the communication in the VANET is done under the North America DSRC standards which employ the IEEE 802.11p s tandard for wireless communication.

Applications and Pros:

Ÿ VANET is employed for vehicle to vehicle communication, communication through messages, sending and receiving of data. Also the data related to different vehicles and the users is also obtained by the communication channel. For example, two vehicles full of friends are travelling on a highway to go on a picnic; they decide to take a stop at the next gas station. What will they use? If it had been some time ago then they would have taken out their mobile phones and communicated with each

other but now they can communicate with each other through VANET.

Ÿ VANET is employed for the communication of the vehicle with the infrastructure i.e. with the Road Side Unit (RSU) which is used to perform different functions. For infotainment in which data and information required by the user on the go is given by the RSU, the system of the vehicle is also updated by the RSU using VANET, the internet can be used through the RSU, weather forecast, information about the road and it's curves, nearby locations, all this and many other facilities are provided by the road side units using VANET.

Ÿ Another application of this RSU aiding the vehicle in a VANET can be understood by the following example. It is a common situation on a highway that whenever an accident occurs, the vehicles following it with speed also becomes the part of the incident. With VANET, this can be avoided and the vehicles following or present in the region can be given the information about the incident through VANET. Another example can be quoted as, whenever there is traffic on the road, the vehicle can be made aware through VANET and alternate feasible route can be selected by the vehicle.

Ÿ Information about the nearby locations can also be found through VANET. The RSU contains all the information about the area, so the information demanded by the user can easily be communicated. Also VANET can be employed to contact the authorities in case of any emergency. In case of vehicular emergency, failure of brakes or anything related to the vehicle, the nearest service station can be given an alert of the malfunction, so that they can get ready.

Ÿ The Dedicated Short Range Communication is used in VANET; an application of DSRC can be understood as follows. Consider a gate that has a DSRC antenna which is capable of sending and receiving data from a recognized vehicle. Whenever a vehicle stops in front of it, it sends a signal thus getting the information about the vehicle. If the vehicle is registered then the antenna wills need a signal to open the gate for the vehicle after the verification of the Electronic License Plate.

Ÿ Threat to AvailabilityŸ Threat to Authentication



There are many phenomenon which take place and pose a threat in VANET. The information that is being broadcasted can be tampered and can be used by the attacker. The confidentiality of the user must be maintained in VANET. As the information local to the users is broadcasted in the network, there should be some method devised strictly to maintain the confidentiality of VANET. For this digital cryptography was employed to generate digital signatures in order to differentiate among the users and only disclose or receive information from the designated user. Another aspect of providing security in VANET is through ELP. The data about the user is basically generated by ELP and the data to be shared is also evaluated and communicated based upon this information.

Security measures must be taken to take control of the VANET and to ensure that it does not go into wrong hands and is saved by malicious attacks. Through message authentication, privacy protection, information confidentiality etc. the security of VANET can be maintained and an efficiently running network can be ensured.

VANET has gained significant importance. It is the need of the hour and has made a great impact on the vehicular communication. It has made possible the communication and the dream of staying connected 24/7 possible. It has provided with many facilities to the users on the go. Due to this technology, accidents are avoided by the information provided to the user in time. Just like an aircraft constantly communicates with the control tower or the base and gets the required information about all the basic things and also notifies the base in case of any malfunction. Similarly in a car through VANET, vehicles can communicate with each other and also with the RSU, thus giving and retrieving information that is useful to them.

Safety of the vehicles is an important aspect which is covered in VANET. The traffic monitoring and information about the vehicle and other vehicles is also provided to the user. Alerts and notices in case of any accident, weather forecast, information about the locations, can easily be obtained in a VANET thus enhancing its importance to great level.

GOING NUCLEAR!

Syed Murtaza IslamOld Ravian

With the world facing the present challenge of

global energy crisis, Nuclear Energy generation is one of the most efficient power production methods available. In the current era, power generation is carried through different methods and electricity is commonly generated through hydropower throughout the world. However, we need to move on to more cost-effective and productive technology such as Nuclear power.

“Nuclear power will help provide the electricity that our growing economy needs without increasing emissions. This is truly an environmentally responsible source of energy.”

- Michael Burgess

Nuclear power:

Nuclear power can be defined as clean, safe, reliable, compact, competitive and practically inexhaustible source of energy. Today over 400 nuclear reactors provide base-load electric power in 30 countries. Fifty years old, it is a relatively mature technology with the assurance of much more improvements in the next generation.



Clean:

Nuclear energy produces almost no carbon dioxide, and no sulphur oxides or nitrogen oxides whatsoever. These gases are produced in vast quantities when fossil fuels are burned.

Nuclear waste:

One gram of uranium yields about as much energy as a ton of coal or oil- it is the famous “factor of a million”. Nuclear waste is correspondingly about a million times smaller than fossil fuel waste, and it is totally confined.

Safe:

Nuclear power is safe, as proven by the record of half a century of commercial operations and with the accumulated experience of more than 12,000 reactor-years.

Reliable:

Nuclear reactors provide base-load power and are available over 90% of the time; intervals between refueling have been extended and down time for refueling has been reduced.

Inexhaustible:

Uranium is found everywhere in the crust of the Earth – it is more abundant than tin, for example, major deposits are found in Canada and Australia. It is estimated that increasing the market price by a factor ten would result in 100 times more uranium coming to market. Eventually we will be able to recover uranium from sea water where 4 billion tons

are dissolved.

Radiation:

Fear of the unknown is the merchandise of anti-nuclear “greens”. They preach fear of radiation in general, fear of radioactive waste in particular, fear of another major accident such as Three Mile Island or Chernobyl, and fear of nuclear weapons proliferation.

Old Fashioned Attitudes:

Ecological organizations such as Greenpeace have consistently had an anti-nuclear bias which is more ideological than factual. An increasing number of environmentalists are now changing their minds about nuclear energy because there are very good, solid, scientific and, above all, environmental reasons to be in favor of nuclear energy.

And as far as nuclear weapons are concerned, I firmly believe that we human are wonderful creatures and intelligent enough that we have built those weapons. The burning question is, are we “wise” enough not to use them? Well, one can bet on intelligence but on wisdom not so much.

Conclusion:

Nuclear power has been proven one of the most efficient ways of power generation. To counter the future energy challenges, we have to depend and make full use of it. To conclude, I believe that well designed, well operated and well maintained nuclear energy is not only clean, but it is also safe, reliable, durable and competitive.



12- Electrical Engineering - Government College University. Electrical... · The Scientiﬁc Ravi...

Documents

Transcript of 12- Electrical Engineering - Government College University. Electrical... · The Scientiﬁc Ravi...