Saturday, 28 July 2012
Wednesday, 4 July 2012
Electrical Power Generation Systems
The process using coal oil and gas as fuel.
Water is pressurized, heated in boilers to superheated steam which is then passed through steam turbines to drive (ac) electrical generators. Coal was the first fuel to be widely used in boilers followed by oil; and nuclear reactors in place of boilers
Main components of a coal fired electrical generating power station
Grid of ehv transmission distributes energy.
The electrical power generated is transformed to an extra high voltage (ehv) for example 132 kV or 400 kV (1 kV is 1000 volts) for efficient travel via transmission lines. It is transformed down to lower voltages for use in towns, homes and factories etc. A 'Grid' of interconnected transmission lines enables stability of the whole system and diversity by sharing the constantly varying loads or large changes in generation.
Inherent heat loss limits efficiency up to 38%
Much heat is lost inherently in the conversion of heat to mechanical energy (and thus to electrical energy) in the water/steam 'cycle' in power stations limiting efficiency to 38% or less. Once the steam has passed through the turbine it is condensed in a condenser still at quite a high temperature before being pressurized and reused in the boiler again. The condenser uses external water to cool the steam and this heat is lost to the sea, if taken from the sea, or river, lake, or via cooling towers to the air.
Ways to increase efficiency and therefore reduce CO2 emission from power stations in the future.
1) If the waste heat (otherwise lost via the condenser) can be used for heating buildings in a local town or in an industrial process it is not wasted and therefore the overall efficiency is considerably increased or doubled.
and/or 2) Increase top (steam or gas) temperature with 'Advanced Supercritical ' or 'CCGT' or 'IGCC' systems. In an 'Advanced Supercritical Station,' steam is raised up to top pressures of 250 to 350 bar, and top temperature of 800 - 700 deg. Efficiencies of up to 50/55% are possible (ref 115).
3) Metal Oxide fuel cells may be practical for converting gas energy to electrical energy at 80% efficiency. The cells operate at 800-900 degC which is self sustaining once up to temperature. Local installations distributing to housing estates or towns could save on transmission equipment. See hydrogen - fuel cell page.
Efficiency could be improved up to 55% with CCGT systems
In a combined cycle gas turbine station (CCGT) gas is burnt in gas turbines to drive alternators and the hot exhaust gas is used to raise steam to drive a turbo alternator.
Examples are a 600 MW station at Baja Mexico, 530 MW Irsching in Bavaria, and a550 MW station at Baglan Bay, Wales which also includes district heating so overall efficiency could rise towards 85% in the latter case.
Carbon capture and storage (sequestration) would enable coal and gas fired power stations to be mostly green (90 % effective probably).
A significant reduction in CO2 emissions, from coal or gas power stations, can be made by adding the capture of the carbon dioxide (in addition to dust and SO2 collection), compress it, liquefy it and store it permanently underground in deep saline aquifers or depleted oil reservoirs (ref 126)(ref141). Up to 90% of CO2 emitted from a power station can be captured in this way from a coal or gas power station (ref135).
The process would cost an extra 20-30% probably bringing it in line with renewable energy sources while extra generation capacity is required to make up for lost efficiency.
The Global Geological site potential for CO2 storage is between 1000 and 10,000 Giga tonnes (Gt) of CO2. The potential for CO2 capture is around 2.6 to 4.9 Gt CO2 (0.7 to 1.3 Gt of carbon) per year (ref 160). The total of all global emissions in 2001 was 24 Gt of CO2 (6.5 Gt of carbon) which is estimated to rise to 38 Gt by 2030 so this process could help for many years to reduce CO2 in the air.
Potential in UK North Sea areas is for 40 giga tonnes of CO2 to be liquefied and stored over 200+years in sandstone (porous) capped with mudstone at 3 mile depth. (ref ST p6 news 16 08 09)
The brine filled aquifer (brine in pore spaces) UTSIRA is solid rock 500 km X 50 km and 200 meters thick, 1000 meters beneath the sea bed under the Sleipner Norwegian oil field. 0.8 million tonnes of CO2 per year has been pumped into the pore spaces for ten years. (One power station would provide 4 million tonnes of CO2 per year) ( ref 127).
An alternative is to inject the CO2 underground, at least 800m (2600feet). CO2 takes on a liquid form under 800 metres underground so is unlikely to escape. (Ref 1 p292). It dissolves into saline water and may eventually become solid mineral carbonates.
IGCC plants with carbon capture and hydrogen production.
An Integrated Gasification Combined Cycle plant (IGCC) lends itself to CO2 separation, with hydrogen as a by product, and efficiencies of power production up to 55%.
Syngas is mainly H2 and CO. Recently, some Integrated Gasification Combined Cycle (IGCC) (ref 120) plants have been built with several more to come. These produce synthetic gas (syngas) from coal or gas which drive a gas turbine/generator acting in a combined cycle with a steam turbine/generator. A by product is hydrogen, a potential fuel, and CO2. The process lends itself to CO2 capture with near zero emissions and storage. Efficiencies of 41 to 44% have been achieved and 55% is expected in future (ref 128). See world coal.
Underground Coal Gasification
Mining coal is expensive or in some locations not possible. An alternative for an IGCC plant in the future is to obtain gas from underground coal gasification.
RWE (owner of N Power) plans an underground gasification trial plant in Germany. Oxygen or enriched air and steam is pumped into the coal seam, ignited, raw syngas extracted. This would require precision drilling, skills similar to that required for offshore drilling.
Most projects are at 500 to 800 m depth, but future projects may be at 1200m . At 1600m CO2 could probably be stored in liquid form.
Cooling towers and chimney at a coal fired power station.
Transformers and grid connections
Electrical Power Generation Systems
The process using coal oil and gas as fuel.
Water is pressurized, heated in boilers to superheated steam which is then passed through steam turbines to drive (ac) electrical generators. Coal was the first fuel to be widely used in boilers followed by oil; and nuclear reactors in place of boilers
Main components of a coal fired electrical generating power station
Grid of ehv transmission distributes energy.
The electrical power generated is transformed to an extra high voltage (ehv) for example 132 kV or 400 kV (1 kV is 1000 volts) for efficient travel via transmission lines. It is transformed down to lower voltages for use in towns, homes and factories etc. A 'Grid' of interconnected transmission lines enables stability of the whole system and diversity by sharing the constantly varying loads or large changes in generation.
Inherent heat loss limits efficiency up to 38%
Much heat is lost inherently in the conversion of heat to mechanical energy (and thus to electrical energy) in the water/steam 'cycle' in power stations limiting efficiency to 38% or less. Once the steam has passed through the turbine it is condensed in a condenser still at quite a high temperature before being pressurized and reused in the boiler again. The condenser uses external water to cool the steam and this heat is lost to the sea, if taken from the sea, or river, lake, or via cooling towers to the air.
Ways to increase efficiency and therefore reduce CO2 emission from power stations in the future.
1) If the waste heat (otherwise lost via the condenser) can be used for heating buildings in a local town or in an industrial process it is not wasted and therefore the overall efficiency is considerably increased or doubled.
and/or 2) Increase top (steam or gas) temperature with 'Advanced Supercritical ' or 'CCGT' or 'IGCC' systems. In an 'Advanced Supercritical Station,' steam is raised up to top pressures of 250 to 350 bar, and top temperature of 800 - 700 deg. Efficiencies of up to 50/55% are possible (ref 115).
3) Metal Oxide fuel cells may be practical for converting gas energy to electrical energy at 80% efficiency. The cells operate at 800-900 degC which is self sustaining once up to temperature. Local installations distributing to housing estates or towns could save on transmission equipment. See hydrogen - fuel cell page.
Efficiency could be improved up to 55% with CCGT systems
In a combined cycle gas turbine station (CCGT) gas is burnt in gas turbines to drive alternators and the hot exhaust gas is used to raise steam to drive a turbo alternator.
Examples are a 600 MW station at Baja Mexico, 530 MW Irsching in Bavaria, and a550 MW station at Baglan Bay, Wales which also includes district heating so overall efficiency could rise towards 85% in the latter case.
Carbon capture and storage (sequestration) would enable coal and gas fired power stations to be mostly green (90 % effective probably).
A significant reduction in CO2 emissions, from coal or gas power stations, can be made by adding the capture of the carbon dioxide (in addition to dust and SO2 collection), compress it, liquefy it and store it permanently underground in deep saline aquifers or depleted oil reservoirs (ref 126)(ref141). Up to 90% of CO2 emitted from a power station can be captured in this way from a coal or gas power station (ref135).
The process would cost an extra 20-30% probably bringing it in line with renewable energy sources while extra generation capacity is required to make up for lost efficiency.
The Global Geological site potential for CO2 storage is between 1000 and 10,000 Giga tonnes (Gt) of CO2. The potential for CO2 capture is around 2.6 to 4.9 Gt CO2 (0.7 to 1.3 Gt of carbon) per year (ref 160). The total of all global emissions in 2001 was 24 Gt of CO2 (6.5 Gt of carbon) which is estimated to rise to 38 Gt by 2030 so this process could help for many years to reduce CO2 in the air.
Potential in UK North Sea areas is for 40 giga tonnes of CO2 to be liquefied and stored over 200+years in sandstone (porous) capped with mudstone at 3 mile depth. (ref ST p6 news 16 08 09)
The brine filled aquifer (brine in pore spaces) UTSIRA is solid rock 500 km X 50 km and 200 meters thick, 1000 meters beneath the sea bed under the Sleipner Norwegian oil field. 0.8 million tonnes of CO2 per year has been pumped into the pore spaces for ten years. (One power station would provide 4 million tonnes of CO2 per year) ( ref 127).
An alternative is to inject the CO2 underground, at least 800m (2600feet). CO2 takes on a liquid form under 800 metres underground so is unlikely to escape. (Ref 1 p292). It dissolves into saline water and may eventually become solid mineral carbonates.
IGCC plants with carbon capture and hydrogen production.
An Integrated Gasification Combined Cycle plant (IGCC) lends itself to CO2 separation, with hydrogen as a by product, and efficiencies of power production up to 55%.
Syngas is mainly H2 and CO. Recently, some Integrated Gasification Combined Cycle (IGCC) (ref 120) plants have been built with several more to come. These produce synthetic gas (syngas) from coal or gas which drive a gas turbine/generator acting in a combined cycle with a steam turbine/generator. A by product is hydrogen, a potential fuel, and CO2. The process lends itself to CO2 capture with near zero emissions and storage. Efficiencies of 41 to 44% have been achieved and 55% is expected in future (ref 128). See world coal.
Underground Coal Gasification
Mining coal is expensive or in some locations not possible. An alternative for an IGCC plant in the future is to obtain gas from underground coal gasification.
RWE (owner of N Power) plans an underground gasification trial plant in Germany. Oxygen or enriched air and steam is pumped into the coal seam, ignited, raw syngas extracted. This would require precision drilling, skills similar to that required for offshore drilling.
Most projects are at 500 to 800 m depth, but future projects may be at 1200m . At 1600m CO2 could probably be stored in liquid form.
Cooling towers and chimney at a coal fired power station.
Transformers and grid connections
Heated Debate over NJ Power-Plant Bill
A controversial bill, know as “LS Power Bill” has recently put New Jersey Governor
Chris Christie under some pressure. The bill, A. 3442, is a reaction to regional
power-grid operator PJM Interconnection's (PJM) reliability pricing model(RPM) that is designed, among other things, toencourage the construction of electric generation through incentive rates. The bill says the state must take action to ensure that enough electric generation is available in the region because the incentives under the PJM’s model have failed.
The goal of A. 3442 is to establish a long-term capacity agreement pilot program to promote construction of qualified in-State electric generation facilities.
Bill Supporters
The legislation would allow for a guaranteed long-term income for developers of several large power plants, and the bill’s supporters claim that it would significantly lower energy rates for residents.
“The guarantees were necessary to obtain financing to construct the 640-megawatt plant along the Delaware River, which would cost from $800 million to $1 billion,” said Tom Hoatson, director of regulatory affairs for LS Power.
If approved, the new plant would create construction jobs for 500 people, and 25 permanent jobs.
Bill Opponents
Opponents of the bill, which include Exelon Corp., say it is an “anticompetitive sweetheart deal that will cost consumers in the long run.”
Challengers claim a move like this would “set the clock back” years, and undo efforts to make electrical-power markets more competitive.
George M. Waidelich, vice president of energy operations for Safeway Inc., says, “we cannot afford an energy surcharge to guarantee billions of dollars of revenue to a few select developers.”
Next Steps
Currently, the bill is under review with Governor Christie. Officials expect that the Governor will likely sign the legislation after his office has secured amendments that address concerns about the bill’s potential negative impact on competition in the electric generation market. The Governor’s office was consulted in the last draft of amendments.
Distribution Transformer
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Power Transformers - Indoor & Outdoor Type
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PRODUCTS RANGE
Power & Distribution Transformers from 25 KVA to 5000 KVA upto 33 KV.
STANDARD
Our transformers are designed and tested as per IS : 2026, BS - 171, IEC - 76 & IEC - 726.
Our transformers are designed and tested as per IS : 2026, BS - 171, IEC - 76 & IEC - 726.
VECTOR GROUP
Transformers will be connected as per vector group reference Dyn 11. Other vector groups can be offered as per specific requirements.
Transformers will be connected as per vector group reference Dyn 11. Other vector groups can be offered as per specific requirements.
TERMINAL ARRANGEMENT
H. V - Bare Bushings or Cable Box, L. V-Bare Bushings or Cable Box. Disconnecting
H. V - Bare Bushings or Cable Box, L. V-Bare Bushings or Cable Box. Disconnecting
TEMPERATURE RISE
Our transformers are designed for a maximum temperature rise of 40/50 degree C of oil/winding. Lower temperature rise can be offered on request.
Our transformers are designed for a maximum temperature rise of 40/50 degree C of oil/winding. Lower temperature rise can be offered on request.
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CORE
The core is constructed from low loss, cold rolled, grain oriented, annealled lamination of electrical sheet steel conforming to the latest international standards. Special frame is built-in-house for clamping the core to reduce the magnetic noise as well as making the whole structure rigid and robust.
The core is constructed from low loss, cold rolled, grain oriented, annealled lamination of electrical sheet steel conforming to the latest international standards. Special frame is built-in-house for clamping the core to reduce the magnetic noise as well as making the whole structure rigid and robust.
WINDINGS
Coils are wound with electrolyte high conductivity paper covered or synthetic enamelled copper conductors. Cooling ducts are provided to keep the hot spot temperature as low as possible. Coils are dried in electric ovens. Rigid connection support and coil clamping is provided to ensure high shot circuit strength.
Coils are wound with electrolyte high conductivity paper covered or synthetic enamelled copper conductors. Cooling ducts are provided to keep the hot spot temperature as low as possible. Coils are dried in electric ovens. Rigid connection support and coil clamping is provided to ensure high shot circuit strength.
INSULATION
Pecompressed board PARMALI Board and JAPANEESE insulation paper of best quality is used.
Pecompressed board PARMALI Board and JAPANEESE insulation paper of best quality is used.
TAPPINGS
A. OFF CIRCUIT TAP CHANGING SWITCHTappings from + 5% to - 5% in steps of 2.5% for HV variation or as per customer's requirement.
A. OFF CIRCUIT TAP CHANGING SWITCHTappings from + 5% to - 5% in steps of 2.5% for HV variation or as per customer's requirement.
B. ON LOAD TAP CHANGER
16 steps OLTC for HV variation from + 5% to - 15% in steps of 1.25% or as per specific requirements. OLTC for remote/auto/parallel operation can also be offered.
16 steps OLTC for HV variation from + 5% to - 15% in steps of 1.25% or as per specific requirements. OLTC for remote/auto/parallel operation can also be offered.
OIL
Oil is tested for resistively, dielectric and acidic characteristic conforming to IS - 335. Before topping up oil is filtered thoroughly.
Oil is tested for resistively, dielectric and acidic characteristic conforming to IS - 335. Before topping up oil is filtered thoroughly.
TANKS
The tanks are made of M.S. steel plates / sheets with adequate bracing & stiffness. Tanks are pressure tested to withstand any type of inside or outside pressure. All the external surfaces are given a primary coat of zinc chromate, red oxide and two finishing coats of grey paint. The inner surfaces are given a coat of heat and oil resisting paint.
The tanks are made of M.S. steel plates / sheets with adequate bracing & stiffness. Tanks are pressure tested to withstand any type of inside or outside pressure. All the external surfaces are given a primary coat of zinc chromate, red oxide and two finishing coats of grey paint. The inner surfaces are given a coat of heat and oil resisting paint.
QUALITY CONTROL AND ROUTINE TESTSAll our transformers undergo rigorous quality control checks and are routine tested as per IS in our fully equipped laboratory. Any specific test required by the customer can also be arranged.
What is the Difference Between AC and DC?
The difference between AC and DC is that AC is an alternating current (the amount of electrons) that flows in both directions and DC is direct current that flows in only one direction; the product that is flowing being electrons. AC power is what fuels our homes. The wires outside of our house are connected at two ends to AC generators. DC is found in batteries and solar cells. Both AC and DC employ magnets to repel electrons. Electrons are negatively charged particles that are one of 3 components that make up an atom. Negative charges will repel negative charges and positive charges will repel positive charges, so one only needs to introduce a negatively charged item next to electrons to force them to move in the opposite direction. Likewise, you can attract electrons by introducing something that is positively charged into their environment drawing the electrons to it. This property of electrons is what allows for AC power to work; that is, they switch directions constantly. The picture to the left is a demonstration of AC power at work. The constant switching of directions is evident in the dotted appearance of the light lines.
DC power was invented by Thomas Edison and first used to power our homes in the late 1800′s. Its main drawback being that in order to receive DC power from a generating station, your home had to be located within a one mile radius of the station. DC power degrades as it moves away from its generating source; the further away, the less power. In addition, it is difficult to convert very high power DC current into the lower power current needed in our homes.
Nikola Tesla discovered AC and sold his design to Westinghouse. AC power degrades very little over 100′s of kilometers. When the power reaches an electrical pole outside our homes, a transformer converts to high voltage (the amount of energy carried with the electrons) to the low voltage needed to fuel our appliances. To convert AC to DC, a device needs an item called a rectifier. Many monorail systems use DC power. In addition, if you have a portable stereo, you may notice a button on the back that can switch from AC to DC; this means that you can power your device by plugging it in (AC) or by using batteries (DC).
History
Main article: History of electrical engineering
Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.[2] In 1775 Alessandro Volta's scientific experimentations devised the electrophorus, a device that produced a static electric charge, and by 1800 Volta developed the voltaic pile, a forerunner of the electric battery.[3]
However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in aconductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.[4]
From the 1830s, efforts were made to apply electricity to practical use in telegraphy. By the end of the 19th century the world had been forever changed by the rapid communication made possible by engineering development of land-line, underwater and, eventually, wireless telegraphy.
Practical applications and advances in such fields created an increasing need for standardized units of measure; it led to the international standardization of the units ohm, volt, ampere, coulomb, and watt. This was achieved at an international conference in Chicago 1893.[5] The publication of these standards formed the basis of future advances in standardisation in various industries, and in many countries the definitions were immediately recognised in relevant legislation.[6]
During these years, the study of electricity was largely considered to be a subfield of physics. It was not until the late 19th century that universities started to offer degrees in electrical engineering. The Darmstadt University of Technology founded the first chair and the first faculty of electrical engineering worldwide in 1882. In the same year, under Professor Charles Cross, the Massachusetts Institute of Technology began offering the first option of Electrical Engineering within a physics department.[7] In 1883Darmstadt University of Technology and Cornell University introduced the world's first courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in the United Kingdom.[8] The University of Missouri subsequently established the first department of electrical engineering in the United States in 1886.[9]
During this period, the work concerning electrical engineering increased dramatically. In 1882, Edison switched on the world's first large-scale electrical supply network that provided 110 volts direct current to fifty-nine customers in lower Manhattan. In 1884Sir Charles Parsons invented the steam turbine which today generates about 80 percent of the electric power in the world using a variety of heat sources. In 1887, Nikola Tesla filed a number of patents related to a competing form of power distribution known as alternating current. In the following years a bitter rivalry between Tesla and Edison, known as the "War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.
The efforts of the two did much to further electrical engineering—Tesla's work on induction motors and polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the stock ticker proved lucrative for his company, which ultimately became General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge.[10]
[edit] Modern developments
During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic UHF experiments of 1888, Heinrich Hertz transmitted (via a spark-gap transmitter) and detected radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point (a distance of 80.4 km / 49.95 miles).[11] In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.[12] John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.[13] In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2,100 miles (3,400 km).[14] In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.[15][16] In 1934 the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.[17]
In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer.[18] In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo missions and the NASA moon landing.[19]
The invention of the transistor in 1947 by William B. Shockley, John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.[20] Starting in 1968, Ted Hoff and a team at Intel invented the first commercial microprocessor, which presaged the personal computer. The Intel 4004 was a 4-bit processor released in 1971, but in 1973 the Intel 8080, an 8-bit processor, made the first personal computer, the Altair 8800, possible.[21]
[edit] Education
Electrical engineers typically possess an academic degree with a major in electrical engineering, electronics engineering, or electrical and electronic engineering. The same fundamental principles are taught in all programs, though emphasis may vary according to title. The length of study for such a degree is usually four or five years and the completed degree may be designated as a Bachelor of Engineering, Bachelor of Science, Bachelor of Technology or Bachelor of Applied Science depending upon the university. The degree generally includes units covering physics, mathematics, computer science, project management and specific topics in electrical engineering. Initially such topics cover most, if not all, of the sub-disciplines of electrical engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree. In many institutions electronic engineering is included as part of an electrical award, sometimes explicitly (such as a [Bachelor of Engineering] (Electrical and Electronic), in others electrical and electronic engineering are considered sufficiently broad and complex to be considered separately.[22]
Some electrical engineers choose to pursue a postgraduate degree such as a Master of Engineering/Master of Science (M.Eng./M.Sc.), a Master of Engineering Management, a Doctor of Philosophy (Ph.D.) in Engineering, an Engineering Doctorate (Eng.D.), or an Engineer's degree. The Master and Engineer's degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy and Engineering Doctorate degrees consist of a significant research component and are often viewed as the entry point to academia. In the United Kingdom and various other European countries, the Master of Engineering is often considered an undergraduate degree of slightly longer duration than the Bachelor of Engineering.[23]
[edit] Practicing engineers
In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa ), Chartered Engineer or Incorporated Engineer (in India, Pakistan, the United Kingdom, Ireland and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients".[24] This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.[25] In other countries, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.[26] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET). The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually.[27] The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.[28][29] Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency. MIET(Member of the Institution of Engineering and Technology) is recognised in Europe as Electrical and computer (technology) engineer [30]
In Australia, Canada and the United States electrical engineers make up around 0.25% of the labor force (see note). Outside of Europe and North America, engineering graduates per-capita, and hence probably electrical engineering graduates also, are most numerous in Taiwan, Japan, and South Korea.[31]
[edit] Tools and work
From the Global Positioning System to electric power generation, electrical engineers have contributed to the development of a wide range of technologies. They design, develop, test and supervise the deployment of electrical systems and electronic devices. For example, they may work on the design of telecommunication systems, the operation of electric power stations, the lighting and wiring of buildings, the design of household appliances or the electrical control of industrial machinery.[32]
Fundamental to the discipline are the sciences of physics and mathematics as these help to obtain both a qualitative and quantitative description of how such systems will work. Today most engineering work involves the use of computers and it is commonplace to use computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.
Although most electrical engineers will understand basic circuit theory (that is the interactions of elements such as resistors, capacitors, diodes, transistors and inductors in a circuit), the theories employed by engineers generally depend upon the work they do. For example, quantum mechanics and solid state physics might be relevant to an engineer working on VLSI (the design of integrated circuits), but are largely irrelevant to engineers working with macroscopic electrical systems. Even circuit theory may not be relevant to a person designing telecommunication systems that use off-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasize strong numerical skills, computer literacy and the ability to understand the technical language and concepts that relate to electrical engineering.
For many engineers, technical work accounts for only a fraction of the work they do. A lot of time may also be spent on tasks such as discussing proposals with clients, preparing budgets and determining project schedules.[33] Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and strong written communication skills are therefore very important.
The workplaces of electrical engineers are just as varied as the types of work they do. Electrical engineers may be found in the pristine lab environment of a fabrication plant, the offices of a consulting firm or on site at a mine. During their working life, electrical engineers may find themselves supervising a wide range of individuals including scientists, electricians, computer programmers and other engineers.
[edit] Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these sub-disciplines, many deal with a combination of them. Sometimes certain fields, such as electronic engineering and computer engineering, are considered separate disciplines in their own right.
[edit] Power
Main article: Power engineering
Power engineering deals with the generation, transmission and distribution of electricity as well as the design of a range of related devices. These include transformers, electric generators, electric motors, high voltage engineering and power electronics. In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called off-grid power systems, which in some cases are preferable to on-grid systems. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.
[edit] Control
Main article: Control engineering
Control engineering focuses on the modeling of a diverse range of dynamic systems and the design of controllers that will cause these systems to behave in the desired manner. To implement such controllers electrical engineers may use electrical circuits, digital signal processors, microcontrollers and PLCs (Programmable Logic Controllers). Control engineering has a wide range of applications from the flight and propulsion systems of commercial airliners to the cruise control present in many modern automobiles. It also plays an important role in industrial automation.
Control engineers often utilize feedback when designing control systems. For example, in an automobile with cruise control the vehicle's speed is continuously monitored and fed back to the system which adjusts the motor's power output accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback.
[edit] Electronics
Main article: Electronic engineering
Electronic engineering involves the design and testing of electronic circuits that use the properties of components such as resistors, capacitors, inductors, diodes and transistors to achieve a particular functionality. The tuned circuit, which allows the user of a radioto filter out all but a single station, is just one example of such a circuit. Another example (of a pneumatic signal conditioner) is shown in the adjacent photograph.
Prior to the second world war, the subject was commonly known as radio engineering and basically was restricted to aspects of communications and radar, commercial radio and early television. Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers and microprocessors. In the mid-to-late 1950s, the term radio engineering gradually gave way to the name electronic engineering.
Before the invention of the integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed a large number—often millions—of tiny electrical components, mainly transistors, into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.
[edit] Microelectronics
Main article: Microelectronics
Microelectronics engineering deals with the design and microfabrication of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as a general electronic component. The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors, inductors) can be created at a microscopic level. Nanoelectronics is the further scaling of devices down to nanometer levels.
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics.
[edit] Signal processing
Main article: Signal processing
Signal processing deals with the analysis and manipulation of signals. Signals can be either analog, in which case the signal varies continuously according to the information, or digital, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the compression, error detection and error correction of digitally sampled signals.
Signal Processing is a very mathematically oriented and intensive area forming the core of digital signal processing and it is rapidly expanding with new applications in every field of electrical engineering such as communications, control, radar, TV/Audio/Video engineering, power electronics and bio-medical engineering as many already existing analog systems are replaced with their digital counterparts. Analog signal processing is still important in the design of many control systems.
DSP processor ICs are found in every type of modern electronic systems and products including, SDTV | HDTV sets, radios and mobile communication devices, Hi-Fi audio equipments, Dolby noise reduction algorithms, GSM mobile phones, mp3 multimedia players, camcorders and digital cameras, automobile control systems, noise cancelling headphones, digital spectrum analyzers, intelligent missile guidance, radar, GPS based cruise control systems and all kinds of image processing, video processing, audio processing and speech processing systems.
[edit] Telecommunications
Main article: Telecommunications engineering
Telecommunications engineering focuses on the transmission of information across a channel such as a coax cable, optical fiber or free space. Transmissions across free space require information to be encoded in a carrier wave to shift the information to a carrier frequency suitable for transmission, this is known as modulation. Popular analog modulation techniques include amplitude modulation and frequency modulation. The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer.
Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver. A key consideration in the design of transmitters is their power consumption as this is closely related to their signal strength. If the signal strength of a transmitter is insufficient the signal's information will be corrupted by noise.
[edit] Instrumentation
Main article: Instrumentation engineering
Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure, flow and temperature. The design of such instrumentation requires a good understanding of physics that often extends beyond electromagnetic theory. For example, flight instruments measure variables such as wind speed and altitude to enable pilots the control of aircraft analytically. Similarly, thermocouples use the Peltier-Seebeck effect to measure the temperature difference between two points.
Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control engineering.
[edit] Computers
Main article: Computer engineering
Computer engineering deals with the design of computers and computer systems. This may involve the design of new hardware, the design of PDAs and supercomputers or the use of computers to control an industrial plant. Computer engineers may also work on a system's software. However, the design of complex software systems is often the domain of software engineering, which is usually considered a separate discipline. Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of devices including video game consoles and DVD players.
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