A New Measurement Technique for Tracking Voltage Phasors, Local System Frequency, and Rate of Change of Frequency
TL;DR: In this paper, the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle, and the theoretical basis of these computations and results of experiments performed in the AEP power system simulation laboratory are also outlined.
Abstract: With the advent of Substation Computer Systems dedicated to protection, control and data logging functions in a Substation, it becomes possible to develop new applications which can utilize the processing power available within the substation. The microcomputer based Symmetrical Component Distance Relay (SCDR) described in the references cited at the end of this paper possesses certain characteristics which facilitate real-time monitoring of positive sequence voltage phasor at the local power system bus. With a regression analysis the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle. This paper describes the theoretical basis of these computations and describes results of experiments performed in the AEP power system simulation laboratory. Plans for future field tests on the AEP system are also outlined.
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TL;DR: In this paper, the authors survey the literature till 2011 on the enabling technologies for the Smart Grid and explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system.
Abstract: The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid.
2,433 citations
01 Jan 2012
TL;DR: This article surveys the literature till 2011 on the enabling technologies for the Smart Grid, and explores three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system.
2,337 citations
Cites methods from "A New Measurement Technique for Tra..."
...Phasor measurements using GPS based time synchronization were introduced in the mid-1980s [22, 196, 252, 197]....
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...Sensor [139, 26] [90, 91] [157, 156] [256] Phasor Measurement Unit [11, 20, 22, 23, 38, 56, 110] [137, 160, 183, 184, 197] [196, 199, 221, 238, 237] [243, 248, 252, 270, 271, 272]...
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Book•
30 Jan 2017
TL;DR: Phasor Measurement Techniques and Applications: Estimation of Nominal Frequency Inputs and Phasor Estimation at Off-Nominal Frequency inputs.
Abstract: Phasor Measurement Techniques.- Phasor Estimation of Nominal Frequency Inputs.- Phasor Estimation at Off-Nominal Frequency Inputs.- Frequency Estimation.- Phasor Measurement Units and Phasor Data Concentrators.- Transient Response of Phasor Measurement Units.- Phasor Measurement Applications.- State Estimation.- Control with Phasor Feedback.- Protection Systems with Phasor Inputs.- Electromechanical Wave Propagation.
1,628 citations
TL;DR: The use of time synchronizing techniques, coupled with the computer-based measurement technique, to measure phasors and phase angle differences in real time is reviewed, and phasor measurement units are discussed.
Abstract: The use of time synchronizing techniques, coupled with the computer-based measurement technique, to measure phasors and phase angle differences in real time is reviewed, and phasor measurement units are discussed. Many of the research projects concerned with applications of synchronized phasor measurements are described. These include measuring the frequency and magnitude of phasor, state estimation, instability prediction, adaptive relaying, and improved control. >
1,126 citations
TL;DR: In this paper, the authors present a state estimation algorithm for the IEEE 118 bus system, which involves an admittance-like matrix with the sparsity of the admittance matrix and converges in one step with the same amount of computation as one iteration of existing estimators.
Abstract: The recent introduction of microprocessors into substations for protection and control makes it possible to measure positive sequence voltage phasors and positive sequence transmission line current phasors in real time. It is necessary to synchronize sampling clocks in various substations in order to put the phasors on a common reference. Techniques for synchronizing sampling along with a method for obtaining positive sequence phasors from samples are reviewed. Although it is possible to use these direct measurements in conventional state estimation algorithms, considerable advantage accrues if the state estimation is reformulated in terms of direct measurements of phasor voltages and currents. The resulting estimation algorithm involves an admittance like matrix with the sparsity of the admittance matrix. The new matrix is real rather than complex even for small X/R ratios for the lines. The algorithm requires no assumptions as to decoupling, flat voltage profiles, small resistance, etc. The algorithm converges in one step with the same amount of computation as one iteration of existing estimators. Examples are given for the IEEE 118 bus system.
437 citations
References
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TL;DR: The effects of aliasing (including pseudoaliasing), picket-fence effect, and leakage in the fast Fourier transform (FFT) are presented.
Abstract: The effects of aliasing (including pseudoaliasing), picket-fence effect, and leakage in the fast Fourier transform (FFT) are presented. A computer program was written to perform the FFT analysis of known inputs. The program has the capability of detecting aliasing by calculating an "aliasing coefficient" (Q), and will increase the sampling frequency and the number of points in the input sequence if aliasing occurs. The term "pseudoaliasing" is a phenomenon which is similar to aliasing (or fold-over) but related to the effects of picket fence and leakage. The "leakage coefficient" (ri) is a quantitative measure of the deviation from the fundamental frequency component with respect to the sampling frequency, when the input sequence has only one frequency component.
265 citations
TL;DR: In this article, the authors derived the performance equation of a high speed distance relay which is based upon the theory of symmetrical components, and a single equation was shown to be adequate for handling all types of faults which are likely to occur on a three-phase power system.
Abstract: The paper derives the performance equation of a high speed distance relay which is based upon the theory of symmetrical components. A single equation is shown to be adequate for handling all types of faults which are likely to occur on a three-phase power system. Errors created by system loading and fault-path resistance are considered. A numerical example illustrates the principle of operation of the relay. The relay is especially suited to a digital computer based protection system.
185 citations
TL;DR: In this article, a new method for detecting changes in the power system frequency, by relating it to a leakage coefficient in the FFT, is presented, and the algorithm computes the deviation of the system frequency from the fundamental component and the best estimate of its rate of change, and finally trips the appropriate amounts of load at the appropriate time delays.
Abstract: A power system disturbance, or operating abnormality, can produce a severe generation and load imbalance, resulting in a rapid frequency decline. The possibility of such a disturbance has led to increased interest in the application of automatic under-frequency protection schemes to restore load/generation balance and to prevent equipment damage. In this paper a new method for detecting changes in the power system frequency, by relating it to a leakage coefficient in the FFT, is presented. The algorithm computes the deviation of the power system frequency from the fundamental component and the best estimate of its rate of change. The algorithm then predicts the percentage generation and load imbalance, and finally trips the appropriate amounts of load at the appropriate time delays.
128 citations
TL;DR: In this paper, a simple and economical technique for measuring voltage phase angles and generator shaft angles is reviewed, and the principle is briefly exposed and its practical operation is illustrated by an experiment in a real power system.
Abstract: A simple and economical technique for measuring voltage phase angles and generator shaft angles is reviewed. The principle is briefly exposed and its practical operation is illustrated by an experiment in a real power system. Due to the importance of accurate time for this application a short survey on time dissemination systems is included. The main part of the paper is devoted to the possible applications of phase angle measurements for the control and monitoring of power systems. The discussion deals with various topics and makes ample reference to available literature. The paper is intended as an information survey for assessing the practical significance of phase angle measurements
75 citations
TL;DR: In this article, the role of impedance relaying in modern transmission line protection systems is discussed and a mathematical model of the relaying process in the presence of transient phenomena which accompany faults is presented.
Abstract: The paper reviews the role of impedance relaying in modern transmission line protection systems The speed and reach of the first zone of an impedance relay are identified as being the most important attributes of a relay The paper develops a mathematical model of the relaying process in the presence of transient phenomena which accompany faults It is shown that there is an uncertainty associated with the impedance estimated by a relay and this uncertainty depends upon the speed with which these estimates are made A quantitative relationship between the relay speed and its reach is obtained
72 citations