| Jan  | ---------------JANUARY BABY-------------------- Pretty/handsome. Loves to dress up. Easily bored. Fussy. Seldom shows emotions. Takes time to Recover when hurt. Sensitive. Down-to-Earth. Stubborn. |
| Feb  | ----------FEBRUARY BABY -------------------- Abstract thoughts. Loves reality and abstract. Intelligent and clever. Changing personality. Attractive. Sexiest out of everyone. Temperamental. Quiet, shy and humble. Honest And loyal. Determined to reach goals. Loves Freedom. Rebellious when restricted. Loves Aggressiveness. Too sensitive and easily hurt. Gets angry really easily but does not show it. Dislikes unnecessary things. Loves making friends But rarely shows it. Horny. Daring and stubborn. Ambitious. Realizing dreams and hopes. Sharp. Loves entertainment and leisure. Romantic on the Inside not outside. Superstitious and ludicrous. Spendthrift. Tries to learn to show emotions.. |
| Mar  | -----------------MARCH BABY -------------------- Attractive personality. Sexy. Affectionate Shy and Reserved. Secretive. Naturally honest, generous And sympathetic. Loves peace and serenity. Sensitive to others. Great kisser. Easily angered. Trustworthy. Appreciative and returns kindness. Hardly shows emotions. Tends to bottle up Feelings. Observant and assesses others. |
| Apr  | ------------------APRIL BABY ------------------- Suave and compromising. Funny and humorous. Stubborn. Very talkative. Calm and cool. Kind and Sympathetic. Concerned and detailed. Loyal. Does Work well with others. Very confident. Sensitive. Positive Attitude. Thinking generous. Good Memory. Clever and knowledgeable. Loves to look For information. Able to cheer everyone up and/or Make them laugh. Able to motivate oneself and Others. Understanding. Fun to be around. Outgoing. Hyper. Bubbly personality. Secretive. Boy/girl crazy. Loves sports, music, leisure and Traveling. Systematic. Hot but has brains. If you |
| May  | -----------------MAY BABY ----------------- Stubborn and hard-hearted. Strong-willed and Highly motivated. Sharp thoughts. Easily angered. Attracts others and loves attention. Deep feelings. Beautiful physically and mentally. Firm Standpoint. Needs no motivation. Shy towards opposite sex. Easily consoled. Systematic (left brain). Loves to Dream. Strong clairvoyance. Understanding. Sickness usually in the ear and neck. Good Imagination. Good physical. Weak breathing. Loves Literature and the arts. Loves traveling. Dislike Being at home. Restless. Not having many children. Hardworking. High spirited.. |
| Jun  | ------------JUNE BABY ------------- You've got the best personality and are an Absolute pleasure to be around. You love to make New friends and be outgoing. You are a great flirt And more than likely have a very attractive Partner. A wicked hottie. It is also more than likely That you have a massive record collection. You Have a great choice in films, and may one day Become a famous actor/actress yourself - heck, You've got the looks for it!!! |
| Jul  | ----------------JULY BABY -------------- Fun to be with. Secretive. Difficult to fathom and to Be understood. Quiet unless excited or tensed. Takes pride in oneself. Has reputation. Easily Consoled. Honest. Concerned about people's Feelings. Tactful. Friendly. Approachable. Emotional temperamental and unpredictable. Easily hurt. Witty and sparkly. Spazzy at times. Not revengeful. Forgiving but never forgets. Dislikes nonsensical and unnecessary things. Guides others physically and mentally. Sensitive And forms impressions carefully. Caring and Loving. Treats others equally. Strong sense of Sympathy. Wary and sharp. Judges people Through observations. Hardworking. No difficulties In studying. Loves to be with friends Always broods About the past and the old friends. Waits for Friends. Never looks for friends. Not aggressive Unless provoked. Loves to be loved. Easily hurt But takes long to recover. |
| Aug | ------AUGUST BABY ------ outgoing personality. Takes risks. Feeds on attention. No self control. Kind hearted. Self confident. Loud and boisterous. VERY revengeful. Easy to get along with and talk to. Has an "every thing's peachy" attitude. Likes talking and singing. Loves music. Daydreamer. Easily distracted. Hates not being trusted. BIG imagination. Loves to be loved. Hates studying. In need of "that someone". Longs for freedom. Rebellious when withheld or restricted. Lives by "no pain no gain" caring. Always a suspect. Playful. Mysterious. "Charming" or "beautiful" to everyone. Stubborn. Curious. Independent. Strong willed. A fighter. |
| Sep  | --------SEPTEMBER BABY --------- Active and dynamic. Decisive and haste but tends to regret. Attractive and affectionate to oneself. Strong mentality. Loves attention. Diplomatic. Consoling, friendly and solves people's problems. Brave and fearless. Adventurous. Loving and caring. Suave and generous. Usually you have many friends. Enjoys making love. Emotional. Stubborn. Hasty. Good memory. Moving, motivates oneself and others. Loves to travel and explore. Sometimes sexy in a way that only their lover can understand. |
| Oct  | ---------------OCTOBER BABY ------------------- Loves to chat. Loves those who love them. Loves to takes things at the centre. Inner and physical beauty. Lies but doesn't pretend. Gets angry often. Treats friends importantly. Brave and fearless. Always making friends. Easily hurt but recovers easily. Daydreamer. Opinionated. Does not care to control emotions. Unpredictable. Extremely smart, but definitely the hottest AND sexiest of them all. |
| Nov  | ---------------NOVEMBER BABY -------------------- Trustworthy and loyal. Very passionate and dangerous. Wild at times. Knows how to have fun. Sexy and mysterious. Everyone is drawn towards your inner and outer beauty and independent personality. Playful, but secretive. Very emotional and temperamental sometimes. Meets new people easily and very social in a group. Fearless and independent. Can hold their own. Stands out in a crowd. Essentially very smart. Usually, the greatest men are born in this month. If you ever begin a relationship with someone from this month, hold on to them because their one of a kind. |
| Dec  | ---------------DECEMBER BABY --------------- This straight-up means your the most good-looking person possible... better than all of these other months! Loyal and generous. Patriotic. Competitive in everything. Active in games and interactions. Impatient and hasty. Ambitious. Influential in organizations. Fun to be with. Easy to talk to, though hard to understand. Thinks far with vision, yet complicated to know. Easily influenced by kindness. Polite and soft-spoken. Having lots of ideas. Sensitive. Active mind. Hesitating tends to delay. Choosy and always wants the best. Temperamental. Funny and humorous. Loves to joke. Good debating skills. Has that someone always on his/her mind. Talkative. Daydreamer. Friendly. Knows how to make friends. Abiding. Able to show character. One guy/girl kind of person. Loveable. Easily hurt. Prone to getting colds. Loves music. |
Thursday, August 25, 2011
What baby are you?
Wednesday, October 13, 2010
Acre of Diamond - Review of a Masterpiece
Acres of Diamond
Russell Conwell wrote a speech called Acres Of Diamonds, which he delivered over 6,000 times around the world; it was eventually published as delivered in Conwell's home town, Philadelphia.
The central idea of the work is that one need not look elsewhere for opportunity, achievement, or fortune -- the resources to achieve all good things are present in your own community.
This theme is developed by an introductory anecdote, told to Conwell by an Arab guide, about a man who wanted to find diamonds so badly that he sold his property and went off in futile search for them; the new owner of his home discovered that a rich diamond mine was located right there on the property. Conwell elaborates on the theme through examples of success, genius, service, or other virtues involving ordinary Americans contemporary to his audience: "dig in your own back-yard!".
Conwell's capacity to establishTemple University
The central idea of the work is that one need not look elsewhere for opportunity, achievement, or fortune -- the resources to achieve all good things are present in your own community.
This theme is developed by an introductory anecdote, told to Conwell by an Arab guide, about a man who wanted to find diamonds so badly that he sold his property and went off in futile search for them; the new owner of his home discovered that a rich diamond mine was located right there on the property. Conwell elaborates on the theme through examples of success, genius, service, or other virtues involving ordinary Americans contemporary to his audience: "dig in your own back-yard!".
Conwell's capacity to establish
Acres of Diamonds:
At the heart of his lecture was a parable Conwell heard while traveling through present-day Iraq in 1870:
There was once a wealthy man named Ali Hafed who lived not far from the River Indus. “He was contented because he was wealthy and wealthy because he was contented.” One day a priest visited Ali Hafed and told him about diamonds.
Ali Hafed heard all about diamonds, how much they were worth, and went to his bed that night a poor man. He had not lost anything, but he was poor because he was discontented, and discontented because he feared he was poor.
Ali Hafed sold his farm, left his family, and traveled toPalestine and then to Europe searching for diamonds. He did not find them. His health and his wealth failed him. Dejected, he cast himself into the sea.
One day, the man who had purchased Ali Hafed’s farm found a curious sparkling stone in a stream that cut through his land. It was a diamond. Digging produced more diamonds — acres of diamonds, in fact. This, according to the parable, was the discovery of the famed diamonds ofGolconda
The point, Conwell says, is that we often dream of fortunes to be made in faraway places. We ought instead to be open to the opportunities that are around us. He illustrates this concept with several other stories, including that of the discovery of gold inCalifornia
Principles of Success:
How can we learn to discover these acres of diamonds in our own backyards?
Maintain a ready mind. Be open to the possibilities around you. Don’t let preconceived notions cloud your judgment. We often overlook the value of something because we believe we already know it.
Look at the familiar in new ways. Conwell lists some important inventions — the snap-button, the cotton gin, the mowing machine — and notes that these were created by everyday people who found new approaches and new uses for commonplace objects.
Learn what people want, then give it to them. Discover a market, and then provide a good or a service. Too many people do this the other way around. They develop a good or a service and then try to market it, try to manufacture desire. You’ll have more success if you see a desire and then try to meet it.
Knowledge is more important than capital. Lack of capital is a common excuse for not starting a business venture. How often have you heard, “You need money to make money?” Nonsense, says Conwell. He gives anecdotes of wealthy people who started with nothing but an idea.
Don’t put yourself down, and don’t belittle your environment. Don’t compare yourself with others. “Believe in the great opportunities that are right here not over there in New York or Boston, but here — for business, for everything that is worth living for on earth. There was never an opportunity greater.” Find the best in what’s around you.
At the heart of his lecture was a parable Conwell heard while traveling through present-day Iraq in 1870:
There was once a wealthy man named Ali Hafed who lived not far from the River Indus. “He was contented because he was wealthy and wealthy because he was contented.” One day a priest visited Ali Hafed and told him about diamonds.
Ali Hafed heard all about diamonds, how much they were worth, and went to his bed that night a poor man. He had not lost anything, but he was poor because he was discontented, and discontented because he feared he was poor.
Ali Hafed sold his farm, left his family, and traveled to
One day, the man who had purchased Ali Hafed’s farm found a curious sparkling stone in a stream that cut through his land. It was a diamond. Digging produced more diamonds — acres of diamonds, in fact. This, according to the parable, was the discovery of the famed diamonds of
The point, Conwell says, is that we often dream of fortunes to be made in faraway places. We ought instead to be open to the opportunities that are around us. He illustrates this concept with several other stories, including that of the discovery of gold in
Principles of Success:
How can we learn to discover these acres of diamonds in our own backyards?
Maintain a ready mind. Be open to the possibilities around you. Don’t let preconceived notions cloud your judgment. We often overlook the value of something because we believe we already know it.
Look at the familiar in new ways. Conwell lists some important inventions — the snap-button, the cotton gin, the mowing machine — and notes that these were created by everyday people who found new approaches and new uses for commonplace objects.
Learn what people want, then give it to them. Discover a market, and then provide a good or a service. Too many people do this the other way around. They develop a good or a service and then try to market it, try to manufacture desire. You’ll have more success if you see a desire and then try to meet it.
Knowledge is more important than capital. Lack of capital is a common excuse for not starting a business venture. How often have you heard, “You need money to make money?” Nonsense, says Conwell. He gives anecdotes of wealthy people who started with nothing but an idea.
Don’t put yourself down, and don’t belittle your environment. Don’t compare yourself with others. “Believe in the great opportunities that are right here not over there in New York or Boston, but here — for business, for everything that is worth living for on earth. There was never an opportunity greater.” Find the best in what’s around you.
Conwell says that inside each of us are the seeds of greatness. “Greatness … really consists in doing great deeds with little means and the accomplishment of vast purposes from the private ranks of life.”
Conclusion
I used to be one of those people who looked for diamonds in faraway places. I dreamed of doing something — I didn’t know what — until one day I found an opportunity that had been in front of me all the time: this site. Have you taken stock of your life lately? Perhaps there are diamonds
I used to be one of those people who looked for diamonds in faraway places. I dreamed of doing something — I didn’t know what — until one day I found an opportunity that had been in front of me all the time: this site. Have you taken stock of your life lately? Perhaps there are diamonds
Toward the end of his life, Russell H. Conwell (1843-1925) observed, "I am astonished that so many people should care to hear this story over again. Indeed, this lecture has become a study in psychology; it often breaks all rules of oratory, departs from the precepts of rhetoric, and yet remains the most popular of any lecture I have delivered in the fifty-seven years of my public life. I have sometimes studied for a year upon a lecture and made careful research, and then presented the lecture just once -- never delivered it again. I put too much work on it. But this had no work on it -- thrown together perfectly at random, spoken offhand without any special preparation, and it succeeds when the thing we study, work over, adjust to a plan, is an entire failure." He then went on to explain to each audience that "acres of diamonds are to be found in this city, and you are to find them. Many have found them. And what man has done, man can do. [They are] are not in far-away mountains or in distant seas; they are in your own back yard if you will but dig for them." These comments provide an excellent introduction to Conwell's book. As I read it, I thought about Dorothy in L. Frank Baum's The Wizard of Oz. Only after a series of adventures far from Kansas did she realize that "there's no place like home." What Conwell has in mind involves far more than such appreciation, however. The tale he shares in this book, concerning a wealthy Persian named Ali Hafed, demonstrates that almost everything we may seek elsewhere is already in our lives and available to us, sitting just outside your back door.
THOUGH Russell H. Conwell's Acres of Diamonds have been spread all over the United States
Thursday, April 8, 2010
Rebranding- The Nigerians' New Perspective
I applaud the recent move by the government through the Ministries of Information and Youth Development in rebranding Nigeria and launching us in a brand new way to the world. But more has to be done than just the rebranding strategy, that is, we have to rebrand not only Nigeria but the Nigerians as well. It has to be a wholesome and total exercise for a befitting achievement. It is not enough to tell the world,”Hey! Look, we are a new Nigeria” while the old Nigerians still dwell in the new Nigeria. It makes a mockery of what we are saying. We need more of the new Nigerians because they will ultimately translate into a new Nigeria.
It is damaging enough that some of are country men and women in diasporas are not representing us in the best way as our ambassadors. Let us take a little walk down where we started and to see the reasons for not just a brand new Nigeria but Nigerians as well. I was reading recently in NewAfrican (a monthly publication directed towards restoring the real image of Africa as against the appalling picture painted by the western media) about Neill Blomkamp’s movie, District 9, where Nigerians are portrayed as criminals terrorizing South Africans, getting involved in all forms of crimes ranging from drugs, women trafficking to armed robbery. I would not like to talk about it because I believe a lot have been said in that regards. But I may want to ask,” Was all that Neill produced wrong?” Believe it or not, most of our predecessors in that foreign land left a bad antecedent for the new migrants. Just like having the same old feelings about a bad uncle no matter how good the children turns to be. You still have reservations for them because of their father. Also the recent case of Faruk AbdulMutallab and the Christmas Eve bomb blast saga has yet added more salt to injury. The global world is now seeing Nigerians as terrorist. This could be confirmed by the recent harassing of Nigerian students in Yemen and other European countries alike or the disdain treatment of Nigerians at foreign immigration centre. Make a visit to any of the embassies and see what Nigeria wanting a greener pasture in foreign land pass through in the hands of the foreign immigration staffs. Just when it is like the Faruk’s news is dying down, another crisis in Jos where hundreds of people lost and is still losing their lives added to the latest smearing of Nigeria’s already devastated image. From terrorists to war tasty nation, always making the negative headlines. This perception of our beloved Nation as that full of terrorist or full of warring people is so disturbing and gets me sick to the guts that I was more than relieved when I heard Prof. Dora Akunyili in collaboration with some private sectors launching a campaign towards rebranding Nigeria.
In the light of this development, I would like to suggest that awareness should be made on the need for Nigerians to rebrand not only our nation but regenerate our attitudes- personal, business, religious and otherwise. Just like the popular Chinese proverb that says, “If everyone sweeps the front of his house, the entire community will be clean”. If only every Nigerian can learn to mean what they say and act on what they believe in, our nation will still be perceived as a terrorist or any other degrading adjective the outside world deems fit for us. It requires a wholesome over haul of the old Nigerians for the new Nigerians. The same people but with different character and of different breed. A total regeneration. A new people with a firm resolution to ‘uphold the honor and glory of Nigeria’. I know I am sounding like one of your priests or preacher in the church but that is the truth of the matter. No one can fail to notice the negative media popularity that Nigeria has. How this is affecting the economic growth of the nation even though our CBN governor does not agree with this fact. People are afraid of Nigerians. Just try chatting with people online and see their reactions when you tell them that you are a Nigerian. Even their sometimes polite way of declining further conversation with you would strike you that some thing is seriously wrong with the country. I have stopped complaining about the country and have since resolved to make a little change starting with myself and with people around me. Truth be told, the country is in a chaotic state morally and attitudinally. The house needs to be put in other and it has to be done individually and then collectively. That’s where we need to start from and every other thing follows suit. Accepting that we have a problem is the first step of solving it. It baffles me that people are ready to talk about how good other nations like America, Britain or other developed or even developing (like Kenya or even our neighbor Ghana, for those who would say that the Western countries have existed before us), their organization and sense of duty. It is only in Nigeria that the security guarding a community claims oblivion of an obvious crime while every other person reports that they are aware. Where public office holders have thrown accountability and integrity to the dogs and behave as lords over the masses they are to serve. Where there is a call for resignation of a public office holder that dares criticize the bad proceedings of the government he or she is serving. Where we have abundantly and still live in abject penury. A nation richly blessed with talents and human resource but lack human labour. Where our citizens win accolades and awards for outstanding performances but fail woefully in their own turf. Where credibility is despised and non accountability hailed. Where the most corrupt are put in charge of fight against corruption. I can go on and on but it is not the time to recount faults rather to offer solutions. We all know that the only way to get rid of the situation is by nipping it from the bud- from our individual lives. We are the only people to put our nation in order through self purgation of these vices that limit our growth. I always tell my friends when they do certain things and claim that it doesn’t matter that, ” The society we all abuse today will take revenge on our future generations if we happen to escape the wrath”. No action of man will not be rewarded, if not now then later in life, maybe not directly but on his generations to come. It’s like a chain reaction where series of actions emanates from a single act whether good or bad alike.
So this vision of rebranding Nigeria should be welcomed by every Nigerian. In the wave of the recent happenings in the country, Nigerians whether at home or in diasporas, must endeavor to be good ambassadors of the country. Knowing that what ever decision we take today will determine the future of our wards and those yet to be born. Let us all join hands with the Ministries of Information and Youth Development and other sectors involved to relaunch Nigeria in a brand new way. Nigeria, Good People Great Nation.
Anthony Ikechukwu Odoh
Thursday, September 10, 2009
Powerline Telecommunication/Communication PLT/PLC
Power Line Communications is a technology that uses electricity power lines to transmit data and voice signals.
The first successful method to make use of power lines for control messages was developed in 1950s. The method, called Ripple Control, was characterized by the use of low frequencies (100-900Hz) giving a low bit rate and a demand on very high transmitter power, often in the region of several 10kWs. This technique provided one-way communications and was mostly used for management of streetlights, load control and tariff switching. The current form of this technology was developed in the early 1990s and the main difference between this one and its predecessors was the use of much higher frequencies and a considerable reduction in signal levels. With this two-way communications was achieved.
Power lines connect the power generation station to a variety of customers dispersed over a wide region. Power transmission is done using varying voltage levels and power line cables. Power line cable characteristics and the number of crossovers play an important role in determining the kind of communication technology that needs to be used.
Based on the voltage levels at which they transfer power lines can be categorized as follows:
1. High-tension lines: There connect electricity generation stations to distribution stations. The voltage level on these lines is typically in the order of hundreds of kilovolts and they run over distances of the order of tens of kilometers.
2. Medium-tension lines: These connect the distribution stations to pole mounted transformers. The voltage levels are of the order of a few kilovolts and they run over distances of the order of a few kilometer.
3. Low-tension lines: These connect pole-mounted transformers to individual households. The voltage levels on these lines are of the order of a few hundred volts and these run over distances of the order of a few hundred meters.
POWER LINE CARRIER COMMUNICATION SYSTEM – A Historical and Technological Description.
The technology has roots going back to the 1940s. It has been used by power utilities for simple telemetry and control of electrical equipment in their networks. What is new is the integration of activities outside the building with those inside the building at a much higher bandwidth, say 2.5mbps or higher – this means voice and data transmission via the mains supply voltage network right through to every power socket in the building, as well as in the reverse direction at high speed.
The research has initially been focused on providing services related to power distribution such as load control, computer networks, remote control and smart homes. These value-added services would open up new markets for the power utilities and hence increase the profit. The moderate demands of these applications make it easier to obtain reliable communication. During the last years the use of Internet has increased. If it would be possible to supply this kind of network communication over the power-line, the utilities could also become communication providers, a rapidly growing market. On the contrary to power related applications, network communications require very high bit rates and in some cases real time responses are needed (such as video and TV). This complicates the design of a communication system but has been the focus of many researchers during the last years. Systems under trial exist today that claim a bit rate of 1Mbs, but our system uses low bit rates, about 10-100Kb/s, and provides services such as computer networks. The power-line was initially designed to distribute power in an effective way, hence it is not adapted for communication and communication methods are needed.
HOW POWER LINE COMMUNICATION WORKS:
The power line communication (PLC) is characterized by its ability to send high frequencies using power line carrier unit (PLCU) over power lines and injecting the frequencies through a coupler linked directly to the power grid. The communication signals are separated from the 50Hz power supply by the means of a band pass filter. The components involved in PLC include:
• The power line carrier unit (PLCU) – which provides the signal transmission and reception
• The coupler – This is used for clamping around a live wire thus transmitting communication signals into the power line.
• The power line modem – This aids in modulating and demodulating of signals.
In PLCU, a low pass will filter the 50Hz signal to the meter and a high pass will filter the signal above 1MHz for data communications while the coupler is used to relay the signals into the electricity supply cable. The PLUC as well as the coupler is required at every node where power line communication is to be established. Other components of the PLC include:
Transformer bypass filter, and the PLC Modem which are located at the subscriber’s/ user end. Also, line repeaters may be used to boost the signals over a long distance to the Modem at the user end. It is to be noted that PLC is a point-to-multipoint technology and thus can share bandwidth to many users within an area that is connected to a power substation.
POWER LINE COMMUNICATION ARCHITECTURE
The architecture of a power line communication involves the network topology that is employed.
Network Topology refers to the way in which the network is physically laid out. Some network topologies in use include:
• Mesh
• Ring
• Star
• Bus
*The bus network topology is most suitable for design because of the Nigerian National Grid System and other existing factor.
COMPONENTS OF POWER LINE COMMUNICATION SYSTEM.
1. Circuit Breaker: This is used to isolate the communication network from the power line. It is also used provide protection to the main communication network.
2. Coupling Capacitor: This insulates the PLC equipment from the high voltage side and feeding the HF signal to the power line. This is because the capacitance of the capacitor is such that it presents high impedance to 50Hz (Cc=1/Wc) current of the high voltage side. Thus preventing it from flowing to earth and with the coupling filter. It represents low impedance to the HF signal allowing same to be fed to the power line.
3. Coupling Filter: The PLC equipment produces High frequency signals. This output signal is then filtered. This coupling filter consists of an impedance transfer, which matches the impedance of the PLC equipment (125ohms) to that of the line (200-400ohms). As a result, it is also called the line-matching unit and serves as a protective and as a transformer.
4. PLC Equipment: This is made of a transmitter and a receiver operating in the carrier frequency range of 24-500Hz.
5. Protection Signaling Equipment: This system maintains the signal received and protects it from being affected.
6. AF Modem for SCADA: This helps in the sending and receiving of data signal.
7. Telephone Switch: This is the exchange or end office that deals with calls switching.
ADVANTAGES OF POWER LINE COMMUNICATION
Some of the advantages of power line communication (PLC) include:
1. It enables more people in different locations to communicate using existing PHCN lines.
2. Power Line Communication provides a simple communication network installation network.
3. It saves cost as no additional cable connections are needed.
4. Power lines carry signals for long distances without requiring regeneration. There near light speed propagation makes them very powerful for fast delivery of video and audio data.
5. There is no topology limitation for power lines.
CHALLENGES OF POWER LINE COMMUNICATION
Some challenges of power line communications include:
1. It has not received full accreditation from standard bodies like IEEE, ETSI, etc.
2. It requires that all data be encrypted before transmission for a secured network.
3. Sometimes older wiring can affect the performance of PLC.
4. PLC systems are usually susceptible to interferences from nearby radio signals due to lack of shielding as power lines are typically unshielded.
5. PLC connections could be rather slow, and
6. It also impacts on the home power usage.
REFERENCES
H.K Ponszeek, Carrier Communication over Power lines, New York: springer-verlang, 1972.
Y.S. Sheriff and S.S. Zahir, “On Power-line Carrier Communication (PLC)” Microelectron. Reliab, vol.24, pp. 781 – 791, 1984.
“Power-line Carrier Application Guild, ”Ecc – 133 – 313, General Electronics Co., Mobile Radio Products Dept, Power line Carrier Product Section, Lynchburg Va., 1974.
J. D. Wang and J. J. Trussell, “Adaptive harmonic noise cancellation with an application to distribution powerline communications” IEEE Trans. Communication, vol. 36, pp. 875-885, July, 1988.
The first successful method to make use of power lines for control messages was developed in 1950s. The method, called Ripple Control, was characterized by the use of low frequencies (100-900Hz) giving a low bit rate and a demand on very high transmitter power, often in the region of several 10kWs. This technique provided one-way communications and was mostly used for management of streetlights, load control and tariff switching. The current form of this technology was developed in the early 1990s and the main difference between this one and its predecessors was the use of much higher frequencies and a considerable reduction in signal levels. With this two-way communications was achieved.
Power lines connect the power generation station to a variety of customers dispersed over a wide region. Power transmission is done using varying voltage levels and power line cables. Power line cable characteristics and the number of crossovers play an important role in determining the kind of communication technology that needs to be used.
Based on the voltage levels at which they transfer power lines can be categorized as follows:
1. High-tension lines: There connect electricity generation stations to distribution stations. The voltage level on these lines is typically in the order of hundreds of kilovolts and they run over distances of the order of tens of kilometers.
2. Medium-tension lines: These connect the distribution stations to pole mounted transformers. The voltage levels are of the order of a few kilovolts and they run over distances of the order of a few kilometer.
3. Low-tension lines: These connect pole-mounted transformers to individual households. The voltage levels on these lines are of the order of a few hundred volts and these run over distances of the order of a few hundred meters.
POWER LINE CARRIER COMMUNICATION SYSTEM – A Historical and Technological Description.
The technology has roots going back to the 1940s. It has been used by power utilities for simple telemetry and control of electrical equipment in their networks. What is new is the integration of activities outside the building with those inside the building at a much higher bandwidth, say 2.5mbps or higher – this means voice and data transmission via the mains supply voltage network right through to every power socket in the building, as well as in the reverse direction at high speed.
The research has initially been focused on providing services related to power distribution such as load control, computer networks, remote control and smart homes. These value-added services would open up new markets for the power utilities and hence increase the profit. The moderate demands of these applications make it easier to obtain reliable communication. During the last years the use of Internet has increased. If it would be possible to supply this kind of network communication over the power-line, the utilities could also become communication providers, a rapidly growing market. On the contrary to power related applications, network communications require very high bit rates and in some cases real time responses are needed (such as video and TV). This complicates the design of a communication system but has been the focus of many researchers during the last years. Systems under trial exist today that claim a bit rate of 1Mbs, but our system uses low bit rates, about 10-100Kb/s, and provides services such as computer networks. The power-line was initially designed to distribute power in an effective way, hence it is not adapted for communication and communication methods are needed.
HOW POWER LINE COMMUNICATION WORKS:
The power line communication (PLC) is characterized by its ability to send high frequencies using power line carrier unit (PLCU) over power lines and injecting the frequencies through a coupler linked directly to the power grid. The communication signals are separated from the 50Hz power supply by the means of a band pass filter. The components involved in PLC include:
• The power line carrier unit (PLCU) – which provides the signal transmission and reception
• The coupler – This is used for clamping around a live wire thus transmitting communication signals into the power line.
• The power line modem – This aids in modulating and demodulating of signals.
In PLCU, a low pass will filter the 50Hz signal to the meter and a high pass will filter the signal above 1MHz for data communications while the coupler is used to relay the signals into the electricity supply cable. The PLUC as well as the coupler is required at every node where power line communication is to be established. Other components of the PLC include:
Transformer bypass filter, and the PLC Modem which are located at the subscriber’s/ user end. Also, line repeaters may be used to boost the signals over a long distance to the Modem at the user end. It is to be noted that PLC is a point-to-multipoint technology and thus can share bandwidth to many users within an area that is connected to a power substation.
POWER LINE COMMUNICATION ARCHITECTURE
The architecture of a power line communication involves the network topology that is employed.
Network Topology refers to the way in which the network is physically laid out. Some network topologies in use include:
• Mesh
• Ring
• Star
• Bus
*The bus network topology is most suitable for design because of the Nigerian National Grid System and other existing factor.
COMPONENTS OF POWER LINE COMMUNICATION SYSTEM.
1. Circuit Breaker: This is used to isolate the communication network from the power line. It is also used provide protection to the main communication network.
2. Coupling Capacitor: This insulates the PLC equipment from the high voltage side and feeding the HF signal to the power line. This is because the capacitance of the capacitor is such that it presents high impedance to 50Hz (Cc=1/Wc) current of the high voltage side. Thus preventing it from flowing to earth and with the coupling filter. It represents low impedance to the HF signal allowing same to be fed to the power line.
3. Coupling Filter: The PLC equipment produces High frequency signals. This output signal is then filtered. This coupling filter consists of an impedance transfer, which matches the impedance of the PLC equipment (125ohms) to that of the line (200-400ohms). As a result, it is also called the line-matching unit and serves as a protective and as a transformer.
4. PLC Equipment: This is made of a transmitter and a receiver operating in the carrier frequency range of 24-500Hz.
5. Protection Signaling Equipment: This system maintains the signal received and protects it from being affected.
6. AF Modem for SCADA: This helps in the sending and receiving of data signal.
7. Telephone Switch: This is the exchange or end office that deals with calls switching.
ADVANTAGES OF POWER LINE COMMUNICATION
Some of the advantages of power line communication (PLC) include:
1. It enables more people in different locations to communicate using existing PHCN lines.
2. Power Line Communication provides a simple communication network installation network.
3. It saves cost as no additional cable connections are needed.
4. Power lines carry signals for long distances without requiring regeneration. There near light speed propagation makes them very powerful for fast delivery of video and audio data.
5. There is no topology limitation for power lines.
CHALLENGES OF POWER LINE COMMUNICATION
Some challenges of power line communications include:
1. It has not received full accreditation from standard bodies like IEEE, ETSI, etc.
2. It requires that all data be encrypted before transmission for a secured network.
3. Sometimes older wiring can affect the performance of PLC.
4. PLC systems are usually susceptible to interferences from nearby radio signals due to lack of shielding as power lines are typically unshielded.
5. PLC connections could be rather slow, and
6. It also impacts on the home power usage.
REFERENCES
H.K Ponszeek, Carrier Communication over Power lines, New York: springer-verlang, 1972.
Y.S. Sheriff and S.S. Zahir, “On Power-line Carrier Communication (PLC)” Microelectron. Reliab, vol.24, pp. 781 – 791, 1984.
“Power-line Carrier Application Guild, ”Ecc – 133 – 313, General Electronics Co., Mobile Radio Products Dept, Power line Carrier Product Section, Lynchburg Va., 1974.
J. D. Wang and J. J. Trussell, “Adaptive harmonic noise cancellation with an application to distribution powerline communications” IEEE Trans. Communication, vol. 36, pp. 875-885, July, 1988.
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