Electricity Generation Development - Essay Example

HNC Electrical Engineering History of power generation—phase transformation During the late nineteenth century and early twentieth century, the understanding of power generation and single-phase connection was in its exploring stage. Renowned scientist Charles P. Steinmetz, could develop a concept of single phase power with the phase angle being 90 degree, with unity magnitude. The changeover to the unity magnitude of 120-degree phase angle revolutionized the power generation to three phase connections. As this offered the symmetry in components, it offered the ability to calculate in an unbalanced three-phase power system. The phenomena was named as “Fortescue components” after the name of famous scientist Charles L. Fortescue, who introduced the method around 1918.....(1) However, it remained difficult to understand the three-phase system working under this concept, as any change in the voltage or current in any single phase could result in the corresponding changes in other two phases as well. Therefore, only two-phase alternating current was used in the power systems and it had 90-degree difference between the phases.(2n) Hence the two-phase power-generating concept was developed. However, we have evidence of using two-phase generators by connecting two single-phase ones, as early as 1890s........(2) Three-phase power generation In simpler terms, three-phase power system is the one that uses three different wires. One wire can be a neutral cable, which facilitates the system to use higher voltages while transmitting low voltages in domestic appliances. However, those machines that use high voltage allocations, the neutral cable requirement is not there as negligible loads are connected between the phases. In three phase power systems the power load is well distributed, as all the three wires have same magnitude of current with balance power load. Most of the countries have their own color-coding of the wires to distinguish the same in case of repairs. The three-phase power system is the widely used power in all industries, as it has balanced power load with uniform phase angle difference. However, the requirement of the household appliances and applications can be met with the single or two-phase systems as well. All electric motors are the fine example of three-phase power usage, as a three phase induction motor runs efficiently and has high starting torque with trouble-free design. The application of such motors can be found in fans, blowers, compressors etc. While these are medium and large size motors, application of very small three phase motors can be found in computer fans etc. The main advantage of using three phase appliances is the cost effectiveness and robust design of the same......(3) Apart from all the phases carrying the balanced load in a linear function and having same voltage for all the three phases, the three-phase power is the most efficient as its smooth waveform quality results in trouble free running of all three phase electrical equipment. This also makes it ideal for high transmission functions at lower costs. Three-phase waveform Given below is the figure explaining the three phase waveform (Image source: http://www.3phasepower.org/) This waveform pertains to the single voltage cycle of a three-phase power system. It is plotted along the time axis from zero to 360 degree. The lines thus formed show the instantaneous voltage or current at a particular time instant, drawn over a time period. The repetition of this power wave cycle will depend on the frequency of the power system (Hz), and the waveform will repeat accordingly 50Hz or 60 Hz ...400Hz times per second. The colour of lines are usually black, red and blue, as these are often accepted universally...............(4) Three-phase vector diagram To understand the vectors correctly it is advisable to look at the phasor diagram, given below, for the voltages and currents. Using the “symmetrical components” method, we will consider only the balanced three-phase circuits, which are in use currently. The unbalanced load in three different phases will not give the proper diagram results. (source: Electrical engineering tutorials, http://powerelectrical.blogspot.com/2007/02/ac-3-phase.html) Here the a,b,c represent the tree lines as red phasors are delta or line voltages. The point ‘o’ represents the neutral and blue phasors representing the ‘wye’ voltages, are the voltages to the neutral. The vectors are supposed to rotate clockwise with the angular velocity “ w=2nf”. The projections of the vectors on the horizontal axis represent the voltages vis-vis the time. Accordingly, the voltages between the points referred can be obtained, as, for example, ‘Vab’ is the voltage at a point relative to point ‘b’. Similarly, the ‘Vca or Vbc’ can be found. The same diagram will hold good for the currents also. While the line currents are the blue vectors, the red vectors will be the currents through the delta load. As given in the diagram the blue and red vectors differ by a phase angle of 30 degrees, with magnitude difference of “under-root 3”......(5) Electricity at work regulations act-1989 This act came into force on April 1st., 1990. The aim of these regulations is to prevent injuries and death, caused by electricity while discharging work activities. The regulations have set up the list of precautions at various levels to avoid any mishaps. Mainly, the regulations are concerned with the prevention of electric shock, burn or explosion or fire caused by electric energy. HASAWA All work places, which include shops, factories, offices, workshops, farms etc. are covered under these regulations, mainly from “Health and Safety at Work Act” (HASAWA) The regulations cover broadly the following: The ways and means to protect from excess current The electrical equipment specifications, with particular reference to their strength and design capabilities. Protective equipment and systems deployed during work activities. Means for isolation and cutting-off the electric supply, as well as the electric connection specifications. The ability and competence to prevent danger of injury from electrical energy at work place, with particular reference to working space, access to it and lighting provided there-in. Means and regulations, for working near or on live electrical conductors. All those involved at the work activities, like employers, employees and other utility providers are responsible to comply with these regulations. Under these regulations, it is the duty of the employer to maintain and test the installed as well as portable equipment at frequent intervals, to avoid any mishap. The relevant officers check such reports as they are responsible for the better compliance of these regulations......(6) Electricity Regulation Act—BSI standards BS 5405 This is the main code of practice for regulations of working on electrical switchgear, including its maintenance. This code is relevant for all types of switchgears up to the power rating of 145 KV. The code regulations have been issued by BSI standards in the year 1976. However, there have been additions to this code in terms of BS 6423 and 6626 during the year 1983 and 1985, repectively. BS 6423 This code of practice is relevant to the working and maintenance of all switchgear equipment up to the power rating of 650V or 1KV. These code regulations have been issued by BSI standards in the year 1983 BS 6626 This code of practice relates to the working and maintenance of electric switchgear equipment for power rating of 650V up to 36 KV. This also includes the control gear and other related equipment. The details for all the above standards have vast affect on the working and maintenance of electrical equipment with the main aim being to take sufficient precautions for avoiding injury or death while working on such machinery at any place......(7) IEE wiring regulations It was a landmark day when the members from British Standards Institution and IEE signed an agreement on 2nd. Oct, 1992 which formed the 16th. Edition of IEE wiring regulations that became the BSI standard 7671. The essence of these regulations is the agreements of BSI with International Electromechanical Commission (IEC) and European Committee for Electromechanical Standardization (CENELEC). While IEE has been free to formulate the wiring regulations independently before this Act, but after 1992, it was required by the essence of these wiring regulations, that IEE must work with CENELEC and also IEC to formulate the appropriate specifications. The coordination has to be through the BSI. Harmonization Document This is a CENELEC document, which must be implemented at national level by all members of CENELEC. This can be done by public announcement of number and date pertaining to this document (HD). Having done so, any member country is free to issue a national standard within the scope of HD, provided it does not conflict with other set standards. Such number and date should be notified to the Central Secretariat. Another norm is EN, which stands for European Norm. These are the more common type of CENELEC standards and same are published by BSI as BS-En standards.....(8) Energy management Different energy management methods relate to the efficient and gainful use of electrical energy and the charges levied for the same. The utility suppliers can make tariff plans based at the usage of energy at different hours. The incentives given for the electricity use during off-peak hours and more tariffs during peak hours can take-off some load, during peak hours. By utilizing power during off peak hours the overall power system load factor can be improved largely. The variable power tariff scheme needs to be formulated after thorough investigation of load demand during various hours of the day and the load factor performance related to the same. A trial run to determine the cost effectiveness and the benefits from such energy management schemes will be useful, before putting the same in action. It is more important for the utility companies in developing countries to restructure their operations on this basis, which can improve their efficiency and decrease the sudden and long lasting load shedding. Green Tariff The best way to go for green tariffs is to change the power supply company from the one that produces power in the conventional way to the company, which produces power using other renewable energy resources. Although, in the beginning, the cost may be higher to contribute to the initial investment of the utility company, the power obtained will be clean and free from health hazards. Switching to green tariffs will include taking power from those companies that produce power through renewable energy resources, like .....(9) Using fossil fuel, as input Using wind energy Using solar power. ______________________________________________________________ BIBLIOGRAPHY In-text citation references (1)Blalock, J. Thomas, “The origins of two-phase power”para 2, available at http://www.3phasepower.org/2phasesystems.htm, (accessed on 26th. May, 2009) (2)Blalock, J. Thomas, “The origins of two-phase power”para 3, available at http://www.3phasepower.org/2phasesystems.htm, (accessed on 26th. May, 2009) (3)“Basics of three-phase power”, available at http://www.articlesbase.com/electronics-articles/basics-of-three-phase-power-252927.html, (accessed on 25th. May 2009) (4)“Three phase electric power”, available at http://www.3phasepower.org/, Para 2,3 and 4 (accessed on 26th May, 2009) (5)“Electrical engineering tutorials”-dt. 28th. Feb. 2007, available at: http://powerelectrical.blogspot.com/2007/02/ac-3-phase.html, para 2 and 3, (accessed on 26th My 2009) (6)“Safe working practices”, “Electricity at Work Regulations 1989”—Torbay Council Available at: http://www.torbay.gov.uk/electricity_at_work.pdf, (accessed on 27th May 2009) (7)“Electricity Safety Code for High Voltage Systems”, Scottish health technical memorandum, available at: www.hfs.scot.nhs.uk/publications/2021-1.pdf -page17(accessed on 27th May 2009) (8)Paul--“Commentry on IEE wiring regulations “, 16th edition book, available at: http://books.google.co.in/books?id=qLekBAZUJloC&pg=PA10&lpg=PA10&dq=IEE+regulations&source=bl&ots=nKa7bofaNQ&sig=eWHC_K5lb_jb9JET1l0abPlvJWA&hl=en&ei=0tkcSvazHs-UkAXOy4yVDQ&sa=X&oi=book_result&ct=result&resnum=10#PPA4,M1 Pages 2 to 6 (accessed on 27th May 2009) (9)“Change to a green supplier”, 28th.Sept. 2007, available at: http://www.reuk.co.uk/Change-to-a-Green-Supplier.htm (accessed on 27th May 2009) Sources used “Commentry on IEE wiring regulations “, 16th edition book, authored by Paul and available at: http://books.google.co.in/books?id=qLekBAZUJloC&pg=PA10&lpg=PA10&dq=IEE+regulations&source=bl&ots=nKa7bofaNQ&sig=eWHC_K5lb_jb9JET1l0abPlvJWA&hl=en&ei=0tkcSvazHs-UkAXOy4yVDQ&sa=X&oi=book_result&ct=result&resnum=10#PPA4,M1 Pages 2 to 6 (accessed on 27th May 2009) Blalock, J. Thomas, “The origins of two-phase power”para 2, available at http://www.3phasepower.org/2phasesystems.htm, (accessed on 26th. May, 2009 “Safe working practices”, “Electricity at Work Regulations 1989”—Torbay Council Available at: http://www.torbay.gov.uk/electricity_at_work.pdf, (accessed on 27th May 2009) Read More