Digital Computer Solution of Electromagnetic Transients in Single-and Multiphase Networks
TL;DR: Electromagnetic transients in arbitrary single- or multiphase networks are solved by a nodal admittance matrix method based on the method of characteristics for distributed parameters and the trapezoidal rule of integration for lumped parameters.
Abstract: Electromagnetic transients in arbitrary single- or multiphase networks are solved by a nodal admittance matrix method. The formulation is based on the method of characteristics for distributed parameters and the trapezoidal rule of integration for lumped parameters. Optimally ordered triangular factorization with sparsity techniques is used in the solution. Examples and programming details illustrate the practicality of the method.
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Book•
01 Oct 1995
TL;DR: In this paper, the authors present a power quality evaluation procedure for the purpose of measuring the power quality of a power supply. But, they do not define the specific classes of power quality problems.
Abstract: CHAPTER 1: INTRODUCTION What is Power Quality? Power Quality -- Voltage Quality Why Are We Concerned About Power Quality? The Power Quality Evaluation Procedure Who Should Use This Book Overview of the Contents CHAPTER 2: TERMS AND DEFINITIONS Need for a Consistent Vocabulary General Classes of Power Quality Problems Transients Long-Duration Voltage Variations Short-Duration Voltage Variations Voltage Imbalance Waveform Distortion Voltage Fluctuation Power Frequency Variations Power Quality Terms Ambiguous Terms CBEMA and ITI Curves References CHAPTER 3: VOLTAGE SAGS AND INTERRUPTIONS Sources of Sags and Interruptions Estimating Voltage Sag Performance Fundamental Principles of Protection Solutions at the End-User Level Evaluating the Economics of Different Ride-Through Alternatives Motor-Starting Sags Utility System Fault-Clearing Issues References CHAPTER 4: TRANSIENT OVERVOLTAGES Sources of Transient Overvoltages Principles of Overvoltage Protection Devices for Overvoltage Protection Utility Capacitor-Switching Transients Utility System Lightning Protection Managing Ferroresonance Switching Transient Problems with Loads Computer Tools for Transients Analysis References CHAPTER 5: FUNDAMENTALS OF HARMONICS Harmonic Distortion Voltage versus Current Distortion Harmonics versus Transients Harmonic Indexes Harmonic Sources from Commercial Loads Harmonic Sources from Industrial Loads Locating Harmonic Sources System Response Characteristics Effects of Harmonic Distortion Interharmonics References Bibliography CHAPTER 6: APPLIED HARMONICS Harmonic Distortion Evaluations Principles for Controlling Harmonics Where to Control Harmonics Harmonic Studies Devices for Controlling Harmonic Distortion Harmonic Filter Design: A Case Study Case Studies Standards of Harmonics References Bibliography CHAPTER 7: LONG-DURATION VOLTAGE VARIATIONS Principles of Regulating the Voltage Devices for Voltage Regulation Utility Voltage Regulator Application Capacitors for Voltage Regulation End-User Capacitor Application Regulating Utility Voltage with Distributed Resources Flicker References Bibliography CHAPTER 8: POWER QUALITY BENCHMARKING Introduction Benchmarking Process RMS Voltage Variation Indices Harmonics Indices Power Quality Contracts Power Quality Insurance Power Quality State Estimation Including Power Quality in Distribution Planning References Bibliography CHAPTER 9: DISTRIBUTED GENERATION AND POWER QUALITY Resurgence of DG DG Technologies Interface to the Utility System Power Quality Issues Operating Conflicts DG on Distribution Networks Siting DGDistributed Generation Interconnection Standards Summary References Bibliography CHAPTER 10: WIRING AND GROUNDING Resources Definitions Reasons for Grounding Typical Wiring and Grounding Problems Solutions to Wiring and Grounding Problems Bibliography CHAPTER 11: POWER QUALITY MONITORING Monitoring Considerations Historical Perspective of Power Quality Measuring Instruments Power Quality Measurement Equipment Assessment of Power Quality Measurement Data Application of Intelligent Systems Power Quality Monitoring Standards References Index INDEX
1,991 citations
TL;DR: The methods presented in this paper are aimed to overcome numerical difficulties of closed mathematical solutions of the frequency-dependent line equations in the time domain.
Abstract: The parameters of transmission lines with ground return are highly dependent on the frequency. Accurate modelling of this frequency dependence over the entire frequency range of the signals is of essential importance for the correct simulation of electromagnetic transient conditions. Closed mathematical solutions of the frequency-dependent line equations in the time domain are very difficult. Numerical approximation techniques are thus required for practical solutions. The oscillatory nature of the problem, however, makes ordinary numerical techniques very susceptible to instability and to accuracy errors. The, methods presented in this paper are aimed to overcome these numerical difficulties.
876 citations
TL;DR: In this article, a method based on partitioning the system's admittance matrix and deriving an efficient time-varying Thevenin's equivalent for the converter part is presented.
Abstract: The number of semiconductor switches in a modular multilevel converter (MMC) for HVDC transmission is typically two orders of magnitudes larger than that in a two or three level voltage-sourced converter (VSC). The large number of devices creates a computational challenge for electromagnetic transient simulation programs, as it can significantly increase the simulation time. The paper presents a method based on partitioning the system's admittance matrix and deriving an efficient time-varying Thevenin's equivalent for the converter part. The proposed method does not make use of approximate interfaced models, and mathematically, is exactly equivalent to modelling the entire network (converter and external system) as one large network. It is shown to drastically reduce the computational time without sacrificing any accuracy. The paper also presents control algorithms and other modelling aspects. The efficacy of the proposed method is demonstrated by simulating a point-to-point VSC-MMC-based HVDC transmission system.
720 citations
Cites methods from "Digital Computer Solution of Electr..."
...Using the trapezoidal integration method, the capacitor can be represented as an equivalent voltage source and a resistor [15] as in (5)...
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...Most EMT programs use Dommel’s algorithm [15], which through the application of trapezoidal integration, converts each dynamic element into a Norton equivalent current source in par-...
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...The trapezoidal rule has been traditionally used in EMT-type programs to construct a time-domain Norton equivalent model of typical power system elements [15] as mentioned at the beginning of Section III-A....
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Book•
10 Aug 1992
TL;DR: In this paper, the authors present a classic power system relaying and power system phenomena including stability protection, reliability, and reliability of the relaying system from a network operator's perspective.
Abstract: ??????????? ????? Stanley Horowitz H Power System Relaying May 13th, 2020 With emphasis on power system protection from the network operator perspective this classic textbook explains the fundamentals of relaying and power system phenomena including stability protection and reliability The fourth edition brings coverage up to date with important advancements in protective relaying due to significant changes in the conventional electric power system that will
696 citations
TL;DR: In this paper, a new simulation tool named EMTP-RV is presented, which uses a new matrix formulation for computing load-flow, steady state and time-domain solutions and an open-architecture graphical user interface (GUI) is developed to maximize flexibility and allow creating and maintaining complex designs.
433 citations
Cites background or methods from "Digital Computer Solution of Electr..."
...The main system of symmetric equations used in [1] is given by: (1) = Yv i This is referred to in the literature as the standard nodal analysis formulation....
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...INTRODUCTION Since its initial concept presented in 1969 [1] the basic EMTP type simulation approach remained unchanged....
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References
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TL;DR: The problem of wave propagation along a transmission system composed of an overhead wire parallel to the (plane) surface of the earth, in spite of its great technical importance, does not appear to have been satisfactorily solved.
Abstract: The problem of wave propagation along a transmission system composed of an overhead wire parallel to the (plane) surface of the earth, in spite of its great technical importance, does not appear to have been satisfactorily solved.1 While a complete solution of the actual problem is impossible, on account of the inequalities in the earth's surface and its lack of conductive homogeneity, the solution of the problem, where the actual earth is replaced by a plane homogeneous semi-infinite solid, is of considerable theoretical and practical interest. The solution of this problem is given in the present paper, together with formulas for calculating inductive disturbances in neighboring transmission systems.
1,216 citations
01 Nov 1967
TL;DR: With this method, direct solutions are computed from sparse matrix factors instead of from a full inverse matrix, thereby gaining a significant advantage in speed, computer memory requirements, and reduced round-off error.
Abstract: Matrix inversion is very inefficient for computing direct solutions of the large sparse systems of linear equations that arise in many network problems. Optimally ordered triangular factorization of sparse matrices is more efficient and offers other important computational advantages in some applications. With this method, direct solutions are computed from sparse matrix factors instead of from a full inverse matrix, thereby gaining a significant advantage in speed, computer memory requirements, and reduced round-off error. Improvements of tea to one or more in speed and problem size over present applications of the inverse can be achieved in many cases. Details of the method, numerical examples, and the results of a large problem are given.
780 citations
IBM1
TL;DR: The method of characteristics provides a simple analytic solution for the transient analysis of a uniform, lossless transmission line that is superior in both speed and accuracy to the familiar method of integrating the differential equations that describe a lumped LC model of the line.
Abstract: The method of characteristics provides a simple analytic solution for the transient analysis of a uniform, lossless transmission line. The interpretation of this solution in terms of equivalent network of the input and output behavior of the transmission line leads to an efficient algorithm which yields not only the input and output responses but also the incident and reflected waves. This method is superior in both speed and accuracy to the familiar method of integrating the differential equations that describe a lumped LC model of the line; but it is not applicable to lossy lines.
333 citations
IBM1
TL;DR: The influence of the computer not only on the modus operandi of circuit design, but also on network theory itself, is discussed and a new approach to ac analysis, using the mixed method and a numerical solution of the matrix eigenvalue problem is described.
Abstract: In this tutorial paper, the influence of the computer not only on the modus operandi of circuit design, but also on network theory itself, is discussed. The topological properties of linear graphs are reviewed and a matrix-topological formulation of the network problem is described. In addition to the classical mesh, node, and cutset methods, a mixed method of analysis is described which is applicable to dc, ac, and transient problems. Numerical methods of solving linear and nonlinear dc network problems are discussed and a new approach to ac analysis, using the mixed method and a numerical solution of the matrix eigenvalue problem, is described. The extension of this method to the transient analysis of linear networks is also explained. Finally, the problem of instability in the numerical integration of differential equations is discussed and several means of solving the problem are outlined.
120 citations
TL;DR: In this paper, the propagation problem is first analyzed in phase quantities at a constant frequency and then with modal transformations in the original differential equations from the model analysis, properties of modal transformation are deduced.
Abstract: This paper will investigate the technique of modal analysis applied to propagation of signals on overhead transmission lines The propagation problem is first analyzed in phase quantities at a constant frequency and then with modal transformations in the original differential equations From the model analysis, properties of modal transformations are deduced This analysis shows that when earth correction terms are used in the description of the transmission line, the propagation constant matrix can be used to determine the modal transformations; it is also demonstrated that to evaluate the phase quantity results numerically it is necessary to perform a modal (eigenvalue) transformation The general equations, evaluated for perfect earth, show that the surge impedance matrix can be used to determine the modal transformations, as has been done by previous authors
102 citations