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FNET
FNET (Frequency monitoring Network; a.k.a. FNET/GridEye, GridEye) is a wide-area power system frequency measurement system. Using a type of phasor measurement unit (PMU) known as a frequency disturbance recorder (FDR), FNET/GridEye is able to measure the power system frequency, voltage, and angle very accurately. These measurements can then be used to study various power system phenomena, and may play an important role in the development of future smart grid technologies. The FNET/GridEye system is currently operated by the Power Information Technology Laboratory at the University of Tennessee (UTK) in Knoxville, Tennessee, and Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. History A phasor measurement unit is an important tool that is used to monitor and study electric power systems. The first PMUs were developed at Virginia Tech in the late 1980s. These devices measure the voltage, frequency and phase angle at buses within the power system. By utilizing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health. With an annual budget of about $8.3 billion (fiscal year 2020), the NSF funds approximately 25% of all federally supported basic research conducted by the United States' colleges and universities. In some fields, such as mathematics, computer science, economics, and the social sciences, the NSF is the major source of federal backing. The NSF's director and deputy director are appointed by the President of the United States and confirmed by the United States Senate, whereas the 24 president-appointed members of the National Science Board (NSB) do not require Senate confirmation. The director and deputy director are responsible for administration, planning, budgeting and day-to-day operations of the foundation, while t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country. During the development of commercial electric power systems in the late-19th and early-20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240 V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phasor Measurement Unit
A phasor measurement unit (PMU) is a device used to estimate the magnitude and phase angle of an electrical phasor quantity (such as voltage or current) in the electricity grid using a common time source for synchronization. Time synchronization is usually provided by GPS or IEEE 1588 Precision Time Protocol, which allows synchronized real-time measurements of multiple remote points on the grid. PMUs are capable of capturing samples from a waveform in quick succession and reconstructing the phasor quantity, made up of an angle measurement and a magnitude measurement. The resulting measurement is known as a synchrophasor. These time synchronized measurements are important because if the grid’s supply and demand are not perfectly matched, frequency imbalances can cause stress on the grid, which is a potential cause for power outages. PMUs can also be used to measure the frequency in the power grid. A typical commercial PMU can report measurements with very high temporal resolution, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yilu Liu
Yilu Liu is a Chinese-American electrical engineer. She is a leader in the development of the FNET GridEye monitoring system for the North American power grid, and is known for her research on electric power systems and smart grids. Liu is UT-ORNL Governor’s Chair Professor of Electrical Engineering and Computer Science at the University of Tennessee, Deputy Director of the Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks (CURENT) at the University of Tennessee, and also holds an affiliation with the Oak Ridge National Laboratory. She is an IEEE Fellow and a member of the National Academy of Engineering. Education and career Liu is a 1982 graduate of Xi'an Jiaotong University. She completed her Ph.D. in 1989 at the Ohio State University. She joined the Virginia Tech faculty in 1990, and was promoted to professor there in 2001. In 2009, she moved to the University of Tennessee as UT-ORNL Governor’s Chair Professor for Power Electronics. Recognition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phasor Measurement Unit
A phasor measurement unit (PMU) is a device used to estimate the magnitude and phase angle of an electrical phasor quantity (such as voltage or current) in the electricity grid using a common time source for synchronization. Time synchronization is usually provided by GPS or IEEE 1588 Precision Time Protocol, which allows synchronized real-time measurements of multiple remote points on the grid. PMUs are capable of capturing samples from a waveform in quick succession and reconstructing the phasor quantity, made up of an angle measurement and a magnitude measurement. The resulting measurement is known as a synchrophasor. These time synchronized measurements are important because if the grid’s supply and demand are not perfectly matched, frequency imbalances can cause stress on the grid, which is a potential cause for power outages. PMUs can also be used to measure the frequency in the power grid. A typical commercial PMU can report measurements with very high temporal resolution, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matrix Pencil
In linear algebra, if A_0, A_1,\dots,A_\ell are n\times n complex matrices for some nonnegative integer \ell, and A_\ell \ne 0 (the zero matrix), then the matrix pencil of degree \ell is the matrix-valued function defined on the complex numbers L(\lambda) = \sum_^\ell \lambda^i A_i. A particular case is a linear matrix pencil A-\lambda B \, with \lambda \in \mathbb C\text\mathbb R\text where A and B are complex (or real) n \times n matrices. We denote it briefly with the notation (A,B). A pencil is called ''regular'' if there is at least one value of \lambda such that \det(A-\lambda B)\neq 0. We call ''eigenvalues'' of a matrix pencil (A,B) all complex numbers \lambda for which \det(A-\lambda B)=0 (see eigenvalue for comparison). The set of the eigenvalues is called the ''spectrum'' of the pencil and is written \sigma(A,B). Moreover, the pencil is said to have one or more eigenvalues at infinity if B has one or more 0 eigenvalues. Applications Matrix pencils play an important ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Power In The United States
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wide Area Synchronous Grid
A wide area synchronous grid (also called an "interconnection" in North America) is a three-phase electric power grid that has regional scale or greater that operates at a synchronized utility frequency and is electrically tied together during normal system conditions. Also known as ''synchronous zones'', the most powerful is the Northern Chinese State Grid with 1,700 gigawatts (GW) of generation capacity, while the widest region served is that of the IPS/UPS system serving most countries of the former Soviet Union. Synchronous grids with ample capacity facilitate electricity trading across wide areas. In the ENTSO-E in 2008, over 350,000 megawatt hours were sold per day on the European Energy Exchange (EEX). Neighbouring interconnections with the same frequency and standards can be synchronized and directly connected to form a larger interconnection, or they may share power without synchronization via high-voltage direct current power transmission lines (DC ties), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smart Grid
A smart grid is an electrical grid which includes a variety of operation and energy measures including: *Advanced metering infrastructure (of which smart meters are a generic name for any utility side device even if it is more capable e.g. a fiber optic router) *Smart distribution boards and circuit breakers integrated with home control and demand response (''behind the meter'' from a utility perspective) **Load control switches and smart appliances, often financed by efficiency gains on municipal programs (e.g. PACE financing) *Renewable energy resources, including the capacity to charge parked (electric vehicle) batteries or larger arrays of batteries recycled from these, or other energy storage. *Energy efficient resources *Sufficient utility grade fiber broadband to connect and monitor the above, with wireless as a backup. Sufficient spare if "dark" capacity to ensure failover, often leased for revenue. Electronic power conditioning and control of the production and distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phasor (sine Waves)
In physics and engineering, a phasor (a portmanteau of phase vector) is a complex number representing a sinusoidal function whose amplitude (''A''), angular frequency (''ω''), and initial phase (''θ'') are time-invariant. It is related to a more general concept called analytic representation,Bracewell, Ron. ''The Fourier Transform and Its Applications''. McGraw-Hill, 1965. p269 which decomposes a sinusoid into the product of a complex constant and a factor depending on time and frequency. The complex constant, which depends on amplitude and phase, is known as a phasor, or complex amplitude, and (in older texts) sinor or even complexor. A common situation in electrical networks powered by time varying current is the existence of multiple sinusoids all with the same frequency, but different amplitudes and phases. The only difference in their analytic representations is the complex amplitude (phasor). A linear combination of such functions can be represented as a linear com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Estimation
In statistical signal processing, the goal of spectral density estimation (SDE) or simply spectral estimation is to estimate the spectral density (also known as the power spectral density) of a signal from a sequence of time samples of the signal. Intuitively speaking, the spectral density characterizes the frequency content of the signal. One purpose of estimating the spectral density is to detect any periodicities in the data, by observing peaks at the frequencies corresponding to these periodicities. Some SDE techniques assume that a signal is composed of a limited (usually small) number of generating frequencies plus noise and seek to find the location and intensity of the generated frequencies. Others make no assumption on the number of components and seek to estimate the whole generating spectrum. Overview Spectrum analysis, also referred to as frequency domain analysis or spectral density estimation, is the technical process of decomposing a complex signal into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Power Transmission
Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a ''transmission network''. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is part of electricity delivery, known as the electrical grid. Efficient long-distance transmission of electric power requires high voltages. This reduces the losses produced by strong currents. Transmission lines use either alternating current (HVAC) or direct current (HVDC). The voltage level is changed with transformers. The voltage is stepped up for transmission, then reduced for local distribution. A wide area synchronous grid, known as an "interconnection" in North America, directly connects generators delivering AC power with the same rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
