Daniel OConnell - Biography of Irish Statesman

Daniel OConnell was an Irish patriot who came to exert enormous influence on the relationship between Ireland and its British rulers during the first half of the 19th century. OConnell, a gifted orator, and charismatic figure rallied the Irish people and helped secure some degree of civil rights for the long-oppressed Catholic population. Seeking reform and progress through legal means, OConnell was not really involved in the periodic Irish rebellions of the 19th century. Yet his arguments provided the inspiration for generations of Irish patriots. OConnells signature political achievement was the securing of Catholic Emancipation. His later Repeal Movement, which sought to repeal the Act of Union between Britain and Ireland, was ultimately unsuccessful. But his management of the campaign, which included Monster Meetings which drew hundreds of thousands of people, inspired Irish patriots for generations. It is impossible to overstate the importance of OConnell to Irish life in the 19th century. After his death, he became a venerated hero both in Ireland and among the Irish who had emigrated to America. In many Irish-American households of the 19th century, a lithograph of Daniel OConnell would hang in a prominent location. Childhood in Kerry O’Connell was born on August 6, 1775, in County Kerry, in the west of Ireland. His family was somewhat unusual in that while Catholic, they were considered members of the gentry, and they owned land. The family practiced an ancient tradition of â€Å"fosterage,† in which a child of wealthy parents would be raised in the household of a peasant family. This was said to make the child deal with hardships, and other advantages would be that the child would learn the Irish language as well as local traditions and folklore practices. In his later youth, an uncle nicknamed â€Å"Hunting Cap† O’Connell doted on young Daniel, and often took him hunting in the rough hills of Kerry. The hunters used hounds, but as the landscape was too rough for horses, the men and boys would have to run after the hounds. The sport was rough and could be dangerous, but young O’Connell loved it. Studies in Ireland and France Following classes taught by a local priest in Kerry, O’Connell was sent to a Catholic school in the city of Cork for two years. As a Catholic, he couldn’t enter the universities in England or Ireland at the time, so his family sent him and his younger brother Maurice to France for further studies. While in France, the French Revolution broke out. In 1793 O’Connell and his brother were forced to flee the violence. They made their way to London safely, but with little more than the clothes on their backs. The passing of Catholic Relief Acts in Ireland made it possible for O’Connell to study for the bar, and in the mid-1790s he studied at schools in London and Dublin. In 1798 O’Connell was admitted to the Irish bar. Radical Attitudes While a student, O’Connell read widely and absorbed current ideas of the Enlightenment, including such authors as Voltaire, Rousseau, and Thomas Paine. He later became friendly with the English philosopher Jeremy Bentham, an eccentric character known for advocating a philosophy of â€Å"utilitarianism.† While O’Connell remained a Catholic for the rest of his life, he also always thought of himself as a radical and a reformer. Revolution of 1798 A revolutionary fervor was sweeping Ireland in the late 1790s, and Irish intellectuals such as Wolfe Tone were dealing with the French in hopes that French involvement could lead to Ireland’s liberation from England. O’Connell, however, having escaped from France, was not inclined to align himself with groups seeking French aid. When the Irish countryside erupted in rebellions of the United Irishmen in the spring and summer of 1798, O’Connell was not directly involved. His allegiance was actually to the side of law and order, so in that sense, he sided with British rule. However, he later said that he wasn’t approving of the British rule of Ireland, but he felt that open revolt would be disastrous. The 1798 uprising was particularly bloody, and the butchery in Ireland hardened his opposition to violent revolution. Legal Career of Daniel OConnell Marrying a distant cousin in July 1802, O’Connell soon had a young family to support. And though his law practice was successful and constantly growing, he was also always in debt. As O’Connell became one of the most successful lawyers in Ireland, he was known for winning cases with his sharp wit and extensive knowledge of the law. In the 1820s O’Connell was deeply involved with the Catholic Association, which promoted the political interests of the Catholics in Ireland. The organization was funded by very small donations which any poor farmer could afford. Local priests often urged those in the peasant class to contribute and become involved, and the Catholic Association became a widespread political organization. Daniel OConnell Runs for Parliament In 1828, OConnell ran for a seat in the British Parliament as the member from County Clare, Ireland. This was controversial as he would be barred from taking his seat if he won, as he was Catholic and Members of Parliament were required to take a Protestant oath. OConnell, with the support of poor tenant farmers who often walked miles to vote for him, won the election. As a Catholic Emancipation bill had recently passed, due in large measure to agitation from the Catholic Association, OConnell was eventually able to take his seat. As might be expected, OConnell was a reformer in Parliament, and some called him by the nickname, The Agitator. His great goal was to repeal the Act of Union, the 1801 law which had dissolved the Irish Parliament and united Ireland with Great Britain. Much to his despair, he was never able to see Repeal become a reality. Monster Meetings In 1843, OConnell mounted a great campaign for Repeal of the Act of Union and held enormous gatherings, called Monster Meetings, across Ireland. Some of the rallies drew crowds of up to 100,000. The British authorities, of course, were greatly alarmed. In October 1843 OConnell planned a huge meeting in Dublin, which British troops were ordered to suppress. With his aversion to violence, OConnell canceled the meeting. Not only did he lose prestige with some followers, but the British arrested and jailed him for conspiracy against the government. Return to Parliament OConnell returned to his seat in Parliament just as the Great Famine ravaged Ireland. He gave a speech in the House of Commons urging aid for Ireland and was mocked by the British. In poor health, OConnell traveled to Europe in hopes of recuperating, and while en route to Rome he died in Genoa, Italy on May 15, 1847. He remained a great hero to the Irish people. A grand statue of OConnell was placed on the main street of Dublin, which was later renamed OConnell Street in his honor.

The Learning Styles Controversy - Arguments For and Against

Format for the Celebration Speech Free Essays

Format for the Celebration Speech Introduction: I. Attention GetterAn attention grabbing statement to get the audience interested in learning about your process II. Connection to the AudienceTell them why they should listen to you (i. We will write a custom essay sample on Format for the Celebration Speech or any similar topic only for you Order Now e. how does learning this process benefit them personally) III. Central Idea/ Thesis StatementA one sentence summary and preview of the entire speech, i. e. What are you teaching them? Body: * Transition Statement * I. Body Area Main IdeaA one sentence summary of the first body area A. Supporting MaterialInformation that confirms, illustrates, explains, etc. the main idea for the body area B. Supporting MaterialInformation that confirms, illustrates, explains, etc. the main idea for the body area * Transition Statement* II. Body Area Main IdeaA one sentence summary of the second body area A. Supporting MaterialInformation that confirms, illustrates, explains, etc. the main idea for the body area B. Supporting MaterialInformation that confirms, illustrates, explains, etc. he main idea for the body area * Transition Statement* III. Body Area Main IdeaA one sentence summary of the third body area A. Supporting MaterialInformation that confirms, illustrates, explains, etc. the main idea for the body area B. Supporting MaterialInformation that confirms, illustrates, explains, etc. the main idea for the body area * Transition Statement* Conclusion: I. Central IdeaRestate the central idea to review the main point of the speech II. Reconnect the Attention GetterReiterat e your attention getter. This makes your speech feel â€Å"complete†) Note: You have some leeway with how to format the body areas for this speech. A Celebration speech or an Informative speech is organized depending upon the information you are sharing about your topic. You should focus on interesting facts, uses, etc. about your topic and should NOT do a recounting of the chronological information about the topic. Audiences quickly become bored with this approach. How to cite Format for the Celebration Speech, Essay examples

Geology fo mars Essay Example For Students

Geology fo mars Essay Geology of Mars by Luke Justis Mars is the planet that is the closest geologically to our own. Still we know little about the planet. All the information that we have is from what we see. We can speculate about the geology of the planet but we will never know for sure what the planet is really made of until we physicallygo there. The information is all from NASA sites or NASA related sites. Mars red color leads us to believe that the planet has large amounts of iron. This red color is the only color that is on the surface besides the poles. There is also a darker area that runs along the equator. It goes around roughly one third of the planet. This is a giant canyon that makes our Grand Canyon look like a scratch. There are also what appear to be old stream channels. This implies that there could have been liquid water on the surface. The surface of Mars is varied greatly between north and south. This has been largely attributed to volcanism and erosion. Mars is similar to our moon in the southern hemisphere. This region is referred to as the Highlands of Mars. The area is pitted with numerous craters that reach between one to four km above the datum. Ejecta from the impact scatter around the crater making a rim like structure. The northern hemisphere is very low compared to the southern hemisphere. In the north the ground level rarely reaches above one km below the datum. This stark contrast between north and south is thought to have happened 3 Gyr ago. The south was continuously bombarded with meteors. The north would get hit but it would erode or volcanic flows would cover it. The north also has evidence of ancient stream channels and at the extreme north and south glaciers are still present in the form of an ice cap. Tharsis: The region known as Tharsis is at the center of a bulge in the planets surface. This giant volcano is 4000 km across and 10 km high. Another bulge is called Elysium and it is about 2000 km across and 5 km high. At the summit of Tharsis are three volcanoes the tallest of these is Olympus Mons. The peak of this volcano is 27 km above the place where Tharsis ends and Olympus Mons begins. The volcano itself was made by periodic eruption over a period of time. The lava is most likely very fluid and would have little pyroclastic activity. The large size of the volcano can be attributed the lack of tectonic activity. Few impact craters on the flank of the volcano suggest that the volcano is relatively young. It is possible though, that volcanism could have been occurring during much of Mars history. Mars volcanoes are very similar to those found on Earth specially those found on Hawaii. Their low shape and large flows are very similar to those in Hawaii. Ash deposits are also very common on Martian volcanoes. Evidence for hydrothermal activity is also another commonly found geologic feature on Mars suggesting even more that there is water on Mars. Water Erosion: The role of water erosion is the most mysterious this geologically about Mars. Large dry valleys and evidence Of ancient flood plains all add to the mystery. Old shore lines in the North suggest that there could have been huge lakes caused by massive floods. The floods could have been caused by the heating of the surface or a change of climate. All these bits and pieces add to the debate of whether or not Mars had large amounts of water like Earth at one time or another. The rate at which the water did carve the stream channels and large valleys is still uncertain. There is supple evidence to suggest that the water ran at a slow pace. The features of these valleys appear to be the product of slow erosion. Branch valley networks are commonly found in the southern hemisphere and some in younger areas. .ufb869a299a5f3ba93db0885e5f8361cf , .ufb869a299a5f3ba93db0885e5f8361cf .postImageUrl , .ufb869a299a5f3ba93db0885e5f8361cf .centered-text-area { min-height: 80px; position: relative; } .ufb869a299a5f3ba93db0885e5f8361cf , .ufb869a299a5f3ba93db0885e5f8361cf:hover , .ufb869a299a5f3ba93db0885e5f8361cf:visited , .ufb869a299a5f3ba93db0885e5f8361cf:active { border:0!important; } .ufb869a299a5f3ba93db0885e5f8361cf .clearfix:after { content: ""; display: table; clear: both; } .ufb869a299a5f3ba93db0885e5f8361cf { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .ufb869a299a5f3ba93db0885e5f8361cf:active , .ufb869a299a5f3ba93db0885e5f8361cf:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .ufb869a299a5f3ba93db0885e5f8361cf .centered-text-area { width: 100%; position: relative ; } .ufb869a299a5f3ba93db0885e5f8361cf .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .ufb869a299a5f3ba93db0885e5f8361cf .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .ufb869a299a5f3ba93db0885e5f8361cf .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .ufb869a299a5f3ba93db0885e5f8361cf:hover .ctaButton { background-color: #34495E!important; } .ufb869a299a5f3ba93db0885e5f8361cf .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .ufb869a299a5f3ba93db0885e5f8361cf .ufb869a299a5f3ba93db0885e5f8361cf-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .ufb869a299a5f3ba93db0885e5f8361cf:after { content: ""; display: block; clear: both; } READ: Gamelan - Music of Indonesia Essay The channels appear to have tributaries that increase the size of the main stream channel. 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Facts Hvdc Essay Example

Facts Hvdc Paper A Paper presented on â€Å"FACTS HVDC TRNAMISSION SYSTEMS† PRESENTED BY NITIN K. MOHURLE (T. E. ELECTRICAL) SHRAM SADHANA TRUST’S COLLEGE OF ENGINEERING TECHNOLOGY BAMBHORI, JALGAON E-mail:- nitin. [emailprotected] com FACTS AND HVDC TRNSMISSION SYSTEMS Nitin Mohurle Shram Sadhana Trust’s College of Engineering And Technology, Jalgaon nitin. [emailprotected] com Abstract — Development of electrical power supplies began more than one hundred years ago. At the beginning, there were only small DC networks within narrow local boundaries, which were able to cover the direct needs of industrial plants by means of hydro energy. With an increasing demand on energy and the construction of large generation units, typically built at remote locations from the load centres, the technology changed from DC to AC. Power to be transmitted, voltage levels and transmission distances increased. FACTS (Flexible AC Transmission System) and HVDC (High Voltage Direct Current) are controllable devices whose functions are to enhance the security, capacity and flexibility of power transmission systems. Application of these components in power systems implies an improvement of transient and voltage stability, power oscillation damping and optimal power flow. DC transmission and FACTS (Flexible AC Transmission Systems) has developed to a viable technique with high power ratings since the 60s. From the first small DC and AC mini networks, there are now systems transmitting 3 4 GW over large distances with only one bipolar DC transmission: 1. 000 2. 000 km or more are feasible with overhead lines. We will write a custom essay sample on Facts Hvdc specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Facts Hvdc specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Facts Hvdc specifically for you FOR ONLY $16.38 $13.9/page Hire Writer With submarine cables, transmission levels of up to 600 – 800 MW over distances of nearly 300 km have already been attained, and cable transmission lengths of up to 1. 300 km are in the planning stage. As a multiterminal system, HVDC can also be connected at several points with the surrounding three-phase network. FACTS is applicable in parallel connection or in series or in a combination of both. The rating of shunt connected FACTS controllers is up to 800 Mvar, series FACTS devices are implemented on 550 and 735 kV level to increase the line transmission capacity up to several GW. The fast development of power electronics based on new and powerful semiconductor devices has led to innovative technologies, such as high voltage dc transmission (HVDC) and flexible ac transmission system (FACTS), which can be applied in transmission and distribution systems. This paper has discussed the application of high voltage power electronics FACTS and HVDC controllers, needs of advance FACTS and HVDC based control for future power system and enhancing system stability and its development. HVDC and FACTS offer major advantages in meeting these requirements. Keywords—SVC Static Var Compensator SC Series Capacitor, VSC, STATCOM I. INTRODUCTION The development of Electric Power Industry follows closely the increase of the demand on electrical energy. Main driving factors for energy consumption are listed in Fig. 1. In the early years of power system developments this increase was extremely fast, also in industrialized countries, many decades with the doubling of energy consumption each 10 years. Such fast increase is nowadays still present in the emerging countries, especially in Far-East. In the industrialized countries the increase is, however, only about 1 to 2 % per year with an estimated doubling of the demand in 30 to 50 years. In next 20 years, power consumption in developing and emerging countries is expected to more than double, whereas in industrialized countries, it will increase only for about 40 %. Fast development and further extension of power systems can therefore be expected mainly in the areas of developing and emerging countries. However, because of a lack on available investments, the development of transmission systems in these countries does not follow the increase in power demand. Hence, there is a gap between transmission capacity and actual power demand, which leads to technical problems in the overloaded transmission systems. Interconnection of separated grids in the developed countries can solve some of these problems, however, when the interconnections are heavily loaded due to an increasing power exchange, the reliability and availability of the transmission will be reduced. A. POWER FACTOR To understand power factor, visualize a horse pulling a railroad car down a railroad track. Because the railroad ties are uneven, the horse must pull the car from the side of the track. The horse is pulling the railroad car at an angle to the direction of the car’s travel. The power required to move the car down the track is the working (real) power. The effort of the horse is the total (apparent) power. Because of the angle of the horse’s pull, not all of the horse’s effort is used to move the car down the track. The car will not move sideways; therefore, the sideways pull of the horse is wasted effort or nonworking (reactive) power. The angle of the horse’s pull is related to power factor, which is defined as the ratio of real (working) power to apparent (total) power. If the horse is led closer to the centre of the track, the angle of side pull decreases and the real power approaches the value of the apparent power. Therefore, the ratio of real power to apparent power (the power factor) approaches 1. As the power factor approaches 1, the reactive (nonworking) power approaches 0. Fig. 2 Reactive Power analogy B. REACTIVE POWER: Reactive power is a concept used by engineers to describe the background energy movement in an Alternating Current (AC) system arising from the production of electric and magnetic fields. These fields store energy which changes through each AC cycle. Devices which store energy by virtue of a magnetic field produced by a flow of current are said to absorb reactive power; those which store energy by virtue of electric fields are said to generate reactive power. Explanation for reactive power says that in an alternating current system, when the voltage and current go up and down at the same time, only real power is transmitted and when there is a time shift between voltage and current both active and reactive power are transmitted. But, when the average in time is calculated, he average active power exists causing a net flow of energy from one point to another, whereas average reactive power is zero, irrespective of the network or state of the system. In the case of reactive power, the amount of energy flowing in one direction is equal to the amount of energy flowing in the opposite direction (or different parts -capacitors, inductors, etc- of a network, exchange the rea ctive power). II. FACTS AND HVDC SYSTEM A. HVDC SYSTEM HVDC was first used commercially 50 years ago. Since then a growing number of transmission schemes have been constructed around the world. HVDC differs from high voltage alternating current, HVAC that the voltage is not alternating 50 or 60 cycles per second but is constant. The advantage of HVDC is that long distance transmission is more efficient as there is no need to charge the capacitance of a transmission line with the alternating voltage. The drawback of HVDC is that one needs more expensive terminals at the line ends. Fig. 3 Typical HVDC converter station using thyristor valves HVDC has a number of properties that makes it different from ac transmission. The most important are: The two stations can be connected to networks that are not synchronized or does not even have the same frequency * Power can be transmitted over very long distances without compensation for the reactive power. Reactive power is power that does not add to the transmitted power, but is a by-product at ac- transmission as the line or cable capacitances has to be charged 50 or 60 times per second. As HVDC has constant voltage it does not gene rate reactive power. See also figure 4. * Only two conductors are needed (or even one conductor if the ground or the sea is used as return) for HVDC compared to thre conductors for alternating current. Fig. 4 Shows the power that is possible to transmit as a function of the distance for ac- cables of various voltage stress compared to HVDC With ac high power can be transmitted short distances or low power long distances. HVDC cables can transmit high power over long distances. B. Flexible Alternating Current Transmission System The objective of incorporating FACTS is into the power system lines are similar to HVDC but greater flexibility are involved like improving real power transfer capability in the lines, prevention of sub synchronous resonance (SSR)oscillations and damping of power swings [1]. FACTS devices have four well-known types which are used in many power systems in the world. ‘Single’ type controller is the types of FACTS that installed in series or shunt in an AC transmission line, while ‘unified’ type controller are the combined converters type of FACTS controllers like UPFC and HVDC. The size of a controller is dependent on the requirements of the network and desired power transmission at loading point Voltage Source Controller (VSC) is sinusoidal voltage and is used in power system and other application. The quality of the sine wave is dependent on the size or amount of the power electronics installed. C. LIMITATIONS OF LARGE AC SYSTEMS In large AC Systems with long distance transmission and synchronous interconnections, technical problems can be expected, which are summarized in Fig. 2. Main problems occur regarding load flow, system oscillations and inter-area oscillations. If systems have a large geographic extension and have to transmit large power over long distances, additional voltage and stability problems can arise. Fig. Limitations of Large AC systems III. FACTS, HVDC AND REACTIVE POWER FACTS has a lot to do with reactive power compensation, and indeed, that used to be the term utilized for the technology in the old days. Reactive power appears in all electric power systems, due to the laws of nature. Contrary to active power, which is what we really want to transmit over our power system, and which performs real work, such as keeping a lamp lit or a motor running, reactive power does not perform any such work. Consequently, in a way one can say that the presence f reactive power in a grid makes it heavier for it to perform its task, i. e. transmit power from A to B (Figure 1), and consequently less efficient than would otherwise be possible. We can also refer to Lenz? law, formulated already in the nineteenth century: Every change in an electrical system induces a counter-reaction opposing its origin. So, as a consequence, if we can minimize the flow of reactive power over the transmission system, we can make the system more efficient and put it to better and more economical use. We cannot altogether do without reactive power, though, because it is intimately linked with grid voltage (500 kV, 400 kV, 220 kV, etc). To get the correct grid voltage, we need the right amount of reactive power in the system. If there is not enough reactive power, the voltage will sag. And vice versa, if there is too much of it, the voltage will be too high. So, to have it in the right amounts at all times, and in the right places of the grid, that is the task to be performed by means of Reactive Power Compensation. Reactive power balance is important also from another point of view: it ensures that valuable space in transmission lines and equipment such as transformers is not occupied by â€Å"idle† reactive power, but rather available for a maximum of useful, active power as in fig. This is particularly crucial in situations where some fault appears in the grid. In such a situation, it will often be a matter of milliseconds for the Reactive Power Compensator, i. e. the FACTS device, to go into action and help restore the stability, and the voltage of the grid, in order to prevent, or mitigate, a voltage collapse. IV. LOSSES Maintaining proper balance of reactive power in the grid is important also from another point of view: too much reactive power flowing in the grid also gives rise to losses, and losses cost money which is always, at the end, charged to the customer. To prevent such losses, it is important that reactive power is not permitted to flow over long distances, because losses grow with the distance that the reactive power is flowing over. Instead, reactive power should be inserted where it is needed, i. e. close to large cities and/or large industry enterprises. This, too, is a task for FACTS HVDC SYSTEM. V. NEED OF REACTIVE POWER COMPENSATION: In Figure , the representation of a capacitor inserted at the middle of the line for its compensation, is illustrated. Fig. 7 Distribution line with a capacitor for a given compensation The phasor diagram illustrated in Figure 8 it is illustrated the effect of the capacitor for a 50% of compensation. Once inserted the compensator, Figure 8, it can operate injecting a voltage in the line according to equation. VI. TECHNOLOGY UNDRRLYING FACTS AND HVDC A. VOLTAGE SOURCE CONVERTER: A new type of HVDC using transistors for the ac/dc conversion has been developed. By using components that can not only switch on the current but also switch it off, making it possible to build voltage source converters (VSC). This type of converters offers many advantages when it comes to transmission of power especially from sustainable energy systems. Fig. 9 VSC converter valve B. SERIES COMPENSATION: Fig. 10 In series compensation, the FACTS is connected in series with the power system. It works as a controllable voltage source. Series inductance occurs in long transmission lines, and when a large current flow causes a large voltage drop. To compensate, series capacitors are connected. C. SHUNT COMPENSATION: In shunt compensation, power system is connected in shunt (parallel) with the FACTS. It works as a controllable current source. Fig. 11 Shunt compensation is of two types: A] Shunt capacitive compensation: This method is used to improve the power factor. Whenever an inductive load is connected to the transmission line, power factor lags because of lagging load current. To compensate, a shunt capacitor is connected which draws current leading the source voltage. The net result is improvement in power factor. B] Shunt inductive compensation: This method is used either when charging the transmission line, or, when there is very low load at the receiving end. Due to very low, or no load  Ã¢â‚¬â€œ very low current flows through the transmission line. Shunt capacitance in the transmission line causes voltage amplification (Ferranti Effect). The receiving end voltage may become double the sending end voltage (generally in case of very long transmission lines). To compensate, shunt inductors are connected across the transmission line. Fig. 12 Use of Power Electronics foe Power Transmission VII. FACTS AND HVDC CONTROLLER A. SHUNT CONNECTED CONTROLLER FACTS controllers can be impedance type, based on thyristors without gate turn-off capability, which are called Static Var Compensator (SVC) for shunt-connected application. Another type of FACTS controllers is converter-based which is usually in the form of a Static Synchronous Compensator (STATCOM). B. STATIC VAR COMPENSATOR Static Var Compensator is â€Å"a shunt connected static Var generator or absorber whose output is adjusted to exchange capacitive or inductive current so as to maintain or control specific parameters of the electrical power system (typically bus voltage)†. SVC is based on thyristors without gate turn-off capability. The operating principal and characteristics of thyristors realize SVC variable reactive impedance. SVC includes two main components and their combination: (1) Thyristor-controlled and Thyristor-switched Reactor (TCR and TSR); and (2) Thyristor-switched capacitor (TSC). In Figure shows the diagram of SVC. C. CONVERTOR BASED COMPENSATOR Static Synchronous Compensator (STATCOM) is one of the key Converter-based Compensators which are usually based on the voltage source inverter (VSI) or current source inverter (CSI), as shown in Figure. Unlike SVC, STATCOM controls the output current independently of the AC system voltage, while the DC side voltage is automatically maintained to serve as a voltage source. Mostly, STATCOM is designed based on the VSI. D. SERIES CONNECTED CONTROLLLER As shunt-connected controllers, series-connected FACTS controllers can also be divided into either impedance type or converter type. The former includes Thyristor-Switched Series Capacitor (TSSC), Thyristor-Controlled Series Capacitor (TCSC), Thyristor-Switched Series Reactor, and Thyristor-Controlled Series Reactor. The latter, based on VSI, is usually in the form of a Static Synchronous Series Compensator (SSSC). The composition and operation of different types are similar to the operation of the shunt-connected peers. E. STATIC SYNCHRONOUS COMPENSATOR As discussed in the previous section, STATCOM is a very popular FACTS controller application effective in transmission system voltage control. Since 1980 when the first STATCOM (rated at 20 Mvar) using force-commutated thyristor inverters was put into operation in Japan , many examples have been installed and the ratings have been increased considerably. APPLYING FLEXIBILITY TO THE ELECTRIC POWER SYSTEM The power industry term FACTS (Flexible AC Transmission Systems) covers a number of technologies that enhance the security, capacity and flexibility of power transmission systems. FACTS solutions enable power grid owners to increase existing transmission network capacity while maintaining or improving the operating margins necessary for grid stability. As a result, more power can reach consumers with a minimum impact on the environment, after substantially shorter project implementation times, and at lower investment costs – all compared to the alternative of building new transmission lines or power generation facilities. The two main reasons for incorporating FACTS devices in electric power systems are: * Raising dynamic stability limits * Provide better power flow control. ADVANTAGES OF FACTS AND HVDC SYSTEMS When implemented on a broad-scale basis, FACTS HVDC technologies deliver the following benefits. * A Rapidly Implemented Installations: FACTS projects are installed at existing substations and avoid the taking of public or private lands. They can be completed in less than 12 to 18 months a substantially shorter timeframe than the process required for constructing new transmission lines. * Increased System Capacity: FACTS provide increased capacity on the existing electrical transmission system infrastructure by allowing maximum operational efficiency of existing transmission lines and other equipment. * Enhanced System Reliability: FACTS strengthen the operational integrity of transmission networks, allowing greater voltage stability and power flow control, which leads to enhanced system reliability and security. Improved System Controllability: FACTS allow improved system controllability by building â€Å"intelligence† into the transmission network via the ability to instantaneously respond to system disturbances and gridlock constraints and to enable redirection of power flows * Seamless System Interconnections: FACTS, in the form of BTB dc-link configurations, can establish â€Å"seamless† interconne ctions within and between regional and local networks, allowing controlled power transfer and an increase in grid stability. DISADVANTAGES OF FACTS * The amount of power that can be send over a transmission line is limited. Origin of the limits varies depending on the length of the line. For short line, the heating of the conductors due to line losses sets a â€Å"thermal† limit. * The power flowing over an AC line is proportional to the sine of the phase angle of the voltage at the receiving and transmitting ends and it never reaches 90 degrees. Hence series capacitors or phase-shifting transformers are used on long lines to improve stability. CONCLUSION Power supply industry is undergoing dramatic change as a result of deregulation and political and economical driving forces in many parts of the world. This new market environment puts growing demands for flexibility and power quality into focus. Also, trade of electric power between countries is gaining momentum, to the benefit of all involved. This calls for the right solutions as far as power transmission facilities between countries as well as between regions within countries are concerned. * As indicated by the acronym, FACTS stands for flexibility in AC power systems. Properly utilized, this offers benefits to users of a variety of kinds. Without the need to reinforce the grid by means of additional or upgraded existing lines and/or substations FACTS brings about: * An increase of synchronous stability of the grid; * Increased power transmission capability; * Increased voltage stability in the grid; * Decreased power wheeling between different power systems; * Improved load sharing between parallel circuits; * Decreased overall system transmission losses; * Improved power quality in grids. The choice of FACTS device in each given case may not be obvious but may need to be made the subject of system studies, taking all relevant requirements and prerequisites of the system into consideration, so as to arrive at the optimum technical and economical solution. In fact, the best solution may often be a combination of devices. Finally, a rough and quick guideline to the use of FACTS in various applications: REFRRENCE: [1] Zhang, B. M. ; Ding, Q. F â€Å"The development of FACTS and its control†, Advances in Power System Control, Operation and Management, APSCOM-97. Fourth International Conference, Vol. 1, Nov. 1997, pp: 48 – 53 [2] Paserba, J. J. ; â€Å"How FACTS controllers benefit AC transmission systems†, Power Engineering Society General Meeting, IEEE, Vol. 2, June 2004, pp:1257 1262 [3] Edris, A, â€Å"FACTS technology development: an update†, Power Engineering Review, IEEE, Vol. 20, Issue 3, March 2000, pp: 599 627 [4] L. Gyugyi, â€Å"Application characteristics of converter-based FACTS controllers†, IEEE Conference on Power System Technology, Vol. , pp. 391 396, Dec. 2000. [5] N. G. Hingorani, L. Gyugyi, Understanding FACTS, Concepts and Technology of Flexible AC Transmission systems, IEEE Press 2000 [6] N. G. Hingorani,â€Å"High power electronics and flexible AC transmission system†, IEEE Power Engineering Review, Vol. 8, No. 7, pp. 3-4, July 1988. [7] IEEE FACTS Terms Definitions Task Force of the FACTS Working Group of the DC and FACTS subcommittee, â€Å"Proposed terms and definitions for Flexible AC Transmission System (FACTS)†, IEEE Trans. on Power Delivery, Vol. 12, No. 4, pp. 1848-1853, Oct. 1997.

View From The Bridge Critique essays

View From The Bridge Critique essays Arthur Millers A View from the Bridge is a modern tragedy set in 1950s Brooklyn about a mans obsession with his niece, and what that obsession ultimately brings about. Eddie Carbone, the protagonist of the play also happens to be the antagonist, because he ultimately is fighting against himself with his desires for his niece. I believe that this play was very predictable from the start; this is why I really did not enjoy it all that much. A View from the Bridge had some interesting parts but to me it was really boring and just didnt go anywhere. To me this play did not go anywhere because I did care for any of the characters. The way that Arthur Miller wrote this play makes it hard for you to care about any of the characters; therefore I also do not care what happens to them. There is Eddie, who comes of as arrogant to me; he is the one that I disliked the most. I really saw no point to his behavior, if Miller had given us more of a reason as to why he had such strong feelings toward Catherine then at least we could have learned what made him tick, but as it is I can not see that. I see no purpose for Alfieri; I think that this play could go on just fine without him. I do see the need for a narrator, but I dont think that Alfieri should have been included in the play itself, I believe this cheapens his position as the narrator. Beatrice and Catherine are two characters that I did not like all that much. I saw no practical purpose for Beatrice in this play, she had no effect on this play at all. I would have liked the Beatrice character a little more had she had more of an impact in the play. The Catherine character was likeable but I believe that she is a big reason why Eddie self-destructs. The way that Rodolpho acted made me not care about his fate. I do believe that Eddie was at least part right when he said that Marco was just looking to get married to become a citizen. I thin...

Autophagy in cancer( colonic adenoma and adenocarcinoma) Literature review

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