File Name: trends in power system protection and control ppt to .zip
Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Growing loads and aging equipment are stressing the system and increasing the risk of widespread blackouts. Modern society depends on reliable and economic delivery of electricity.
Moreover, effective and significant utilization of intermittent renewable generation located away from major load centers cannot be accomplished without significant additions to the transmission system. In addition, distribution systems often are incompatible with demand-side options that might otherwise be economical.
The U. This massive system delivers power from the nearly power plants in the United States to virtually every building and facility in the nation. The focus is on the technologies involved—their potential performance, costs, and impacts—and potential barriers to such a deployment in the United States over the next several decades.
The high-voltage transmission system or grid transmits electric power from generation plants through , miles of high-voltage kilovolts [kV] up to kV electrical conductors and more than 15, transmission substations.
The transmission system is configured as a network, meaning that power has multiple paths to follow from the generator to the distribution substation. The distribution system contains millions of miles of lower-voltage electrical conductors that receive power from the grid at distribution substations.
The power is then delivered to million customers via the distribution system. In contrast to the transmission system, the distribution system usually is radial, meaning that there is only one path from the distribution substation to a given consumer. Federal, state, and municipal governments and customer-owned cooperatives all own parts of these systems, but approximately 80 percent of power transactions occur on lines owned by investor-owned regulated utilities IOUs.
In the past, this was the dominant model, but deregulation in some states has transformed the industry. In deregulated areas, generation, transmission, and distribution may be handled by different entities. For example, independent power producers IPPs may sell power to distribution utilities, or even directly to end users, using the transmission system as a common carrier as shown in Figure 9.
The system includes 60, distribution substations. As part of its new authority, FERC has in turn granted the North American Electric Reliability Corporation NERC —a private organization created by the utility industry in to advise on reliability—the authority to develop and enforce reliability standards.
The National Institute of Standards and Technology also is involved in developing standards for the grid. IOUs typically provide electricity to end users through their own distribution systems, while IPPs sell to a utility or purchase transmission services to deliver electric power directly to an end user. There are also utilities that are federally or locally owned, such as municipal and rural co-ops. Seven of the nine come. Market-clearing transactions match the available supply of electric power at a clearing price that matches the demand.
Regions in which the power industry has been restructured, such as Texas, the Northeast, the Upper Midwest, and much of California, are colored. In the white regions, where the industry has not been restructured, vertically integrated power utilities continue to operate the transmission system. The remaining two are subject to Canadian regulations. The Quebec Interconnection is shown as part of the Eastern Interconnection because operations are coordinated.
The Western Interconnection, which extends from the Pacific coast to the Rockies;. The Quebec Interconnection, which is shown in Figure 9. Within each interconnection, all generators operate in synchronism with each other. That is, the Hertz alternating current AC is exactly in phase across the entire interconnection.
While all interconnections operate at 60 Hz, no attempt is made to synchronize them with each other. Electricity is transmitted between interconnections, but that is done by converting to direct current DC and then back to AC. Controlling the dynamic behavior of this interconnected transmission system presents an engineering and operational challenge.
Demand for electricity is constantly changing as millions of consumers turn on and off appliances and industrial equipment. The generation of and demand for electricity are balanced regionally by about balancing authorities to ensure that voltage and frequency are maintained within narrow limits typically 5 percent for voltage and 0. If more power is drawn from the grid than is being pumped into it, the frequency and voltage will decrease, and vice versa.
If the voltage or frequency strays too far from its prescribed level, the resulting stresses can lead to system collapse and possibly damage to power system equipment. Most U. Since , electricity generation has risen from about 3 trillion kilowatt-hours kWh to about 4 trillion in Long-distance transmission has grown even faster for reliability and economic reasons, including new competitive wholesale markets for electricity, but few new transmission lines have been built to handle this growth.
Figure 9. However, in the late s, the restructuring and re-regulation of the U. The stress on the U. Ironically, new transmission lines also are the object of considerable public opposition even while the need for them is increased by opposition to generating stations. Reserve margin is the amount of transmission capacity available above the maximum power expected to be delivered over the system. Some margin is necessary to allow for unexpected loads or outages on the system.
The IOU data cover only 80 percent of the transmission system. All investment is shown in dollars. Sources: — from EEI, ; — from Owens, The deficit of the late s is still affecting reliability; it has contributed to transmission bottlenecks and other transmission deficiencies throughout North America, even with the more recent upward trend in transmission expenditures since According to NERC, the transmission system is being operated at or near its physical limits more of the time Nevius, Stressed grids have less reserve margin for handling disturbances.
TLR is a measure of when scheduled transmission requests could not be accommodated. Transmission loading relief TLR is a sequence of actions taken to avoid or remedy potential reliability concerns associated with the transmission system. Calls for TLRs involve problems. The number of TLR events is not an outage measure; it is the number of times a congestion limit is reached.
Although this measure has been used to characterize transmission reliability, congestion limits can be reached purely for market reasons. Source: See www. Each event affected 50 million people. Today, essentially all large power-transmission equipment is imported from Europe and Japan. This could become a potentially. These may or may not result in transmission outages or outages to customers. Disturbances include electric service interruptions, unusual occurrences, demand and voltage reductions, public appeals, fuel supply problems, and acts of sabotage that can affect the reliability of the bulk electric systems.
Source: Compiled from data in NERC, , , , , , , , , , , , , and Modernization is progressing much more rapidly abroad. About 30 high-power HVDC projects are under construction in Europe, including many submarine cable connections to increase utilization of offshore wind power.
Two-way metering is common in Europe because it helps to maximize the potential of rooftop photovoltaics, which are being heavily promoted in Germany and other countries. Although the United States has vast potential for wind and solar generation, there is no consensus or plan for how this power could be transmitted to load centers. To meet these challenges, transmission.
Two major issues contributed to this blackout: first, the operators did not know the system was in trouble; and second, there was poor communication between the utilities operating the transmission lines—First Energy and American Electric Power—and also between these utilities and the ISO responsible for the area the Midwest Independent System Operator.
Adequate monitoring, communication, and dynamic reactive power support during the initial voltage sag could have helped to prevent lines from overloading, heating up, and sagging excessively. Operators would have been better informed, and online real-time dynamic contingency analysis of potential system collapse would have helped operators stay aware of possible risks and actions to be taken in response.
Finally, automatic actions could have been taken to island isolate portions of the system and prevent the ultimate cascading event which spread the localized outage across much of the northeast United States and Canada.
The system could also have been restored much more rapidly if a modern grid had been in place. Thus if business continues as usual, investment will focus on new construction to meet peak load growth, which is projected to increase. This view was presented repeatedly to the committee by industry representatives, including those representing Southern California Edison Co. Distribution systems are in better condition.
Reliability, for example, has increased steadily over the last 7 years—in part because these systems have to be enlarged to handle new consumers. Public utility commissions usually provide revenue incentives based on indexes, shown in Annex 9. A , that directly measure customer service reliability. Consequently, the distribution companies have improved or at least held steady their customer outage statistics. Growth provides the opportunity for distribution companies to introduce new and smarter technologies on a limited basis before undertaking a wider application.
For example, a utility can introduce modern, smart technologies on a substation-by-substation basis as it is determined that portions of the distribution network need upgrading. For example, the present system of local automatic controls overseen by human operators at regionally based control centers is not able to adequately foresee that disturbances in Cleveland can black out New York, Toronto, and Detroit, or that transmission outages in Switzerland can black out all of Italy.
Modern communications and controls can move much faster to diagnose problems and bypass or isolate them. The same technology can provide cost benefits by maximizing power flows and integrating power from renewable energy sources. New technology is an important part of the answer to the challenges facing the grid, but policy and regulatory changes will also be needed, particularly with.
Some lowering of this number may be possible with aggressive electricity end-use efficiency measures. The steady reliability of the distribution system does not contradict the increasing congestion and increasing number of system disturbances on the transmission system.
Outages on the transmission system do not necessarily result in outages on the distribution system, as the transmission system is a network. This means that if one path is closed, there are alternative paths for power to flow to the consumer. For example, the cost of not having power when it is needed is far greater to the user than the lost revenues to the utility that cannot provide it. Recognizing the value of a reliable, efficient, and flexible grid, and supporting the investments to make that possible, may require a national-level strategy.
As discussed below in this chapter, expanding and modernizing distribution systems will require considerably more investment than for transmission systems. Much of the expansion will be noncontroversial because it will be required to meet growing loads and can be done without much impact on people who do not directly benefit from it. In addition, modernization of distribution can be achieved on a more limited basis than for transmission, which will require coordination across many systems.
An electrical grid , electric grid or power grid , is an interconnected network for delivering electricity from producers to consumers. It consists of: . Electrical grids vary in size from covering a single building through national grids which cover whole countries to transnational grids which can cross continents. Power stations connected to grids are often located near energy resources such as a source of fuel or to take advantage of renewable energy resources, and away from heavily-populated areas. A bulk-power transmission network is therefore used to move the power long distances, sometimes across international boundaries, until it reaches its wholesale customer usually the organisation that owns the local electric power distribution network.
Nfv Ppt Reference of the. We also develop an abstraction for building efficient network functions on G-NET, which significantly reduces development efforts. NFV is the virtualization of network functions e. ONAP, a Linux Foundation project, automates service deployment, lifecycle management, ongoing monitoring and service assurance. Design meeting. NFV extends virtualization technology to network infrastructure. This seminar is being offered at various locations and a recorded live stream is now available.
Some of the fundamentals of the risk management system are expanded upon in Part 1. Risk Management refers to the exercise or practice of forecasting the potential risks thus analyzing and evaluating those risks and taking some corrective measures to reduce or minimize those risks. Download the best free Powerpoint templates to create modern presentations.
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This article gives a list of the most popular and latest seminar topics for electrical engineering students. These electrical seminar topics are an essential part of the curriculum during engineering. Choosing the best seminar topic is essential not only from an academic point of view but also from the knowledge point of view. Because the selection of the best topics enhances the knowledge of the students about the latest topics as well as the latest technology. This article list out recent advanced electrical seminar topics for electrical engineering students.
В этом нет необходимости, - ответил на это Беккер. Он так или иначе собирался вернуть деньги. Он поехал в Испанию не ради денег. Он сделал это из-за Сьюзан. Коммандер Тревор Стратмор - ее наставник и покровитель. Сьюзан многим ему обязана; потратить день на то, чтобы исполнить его поручение, - это самое меньшее, что он мог для нее сделать.
Фонтейн молча обдумывал информацию. - Не знаю, ключ ли это, - сказал Джабба. - Мне кажется маловероятным, что Танкадо использовал непроизвольный набор знаков. - Выбросьте пробелы и наберите ключ! - не сдержался Бринкерхофф.
Понятно. Она получит ваше письмо утром.
Элементарная ошибка, подумала Сьюзан, Стратмор, по-видимому, поменял местами поля информации, и Следопыт искал учетные данные совсем не того пользователя. Она завершила ввод данных и запустила Следопыта. Затем щелкнула по кнопке возврат. Компьютер однократно пискнул.
Я просто попал на все готовое. Поверь. Поэтому я и узнал о его намерении модифицировать Цифровую крепость. Я читал все его мозговые штурмы. Мозговые штурмы.
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