Author
Hermann W. Dommel
Other affiliations: Bonneville Power Administration
Bio: Hermann W. Dommel is an academic researcher from University of British Columbia. The author has contributed to research in topics: Emtp & Electric power system. The author has an hindex of 32, co-authored 81 publications receiving 5884 citations. Previous affiliations of Hermann W. Dommel include Bonneville Power Administration.
Papers published on a yearly basis
Papers
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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.
1,578 citations
TL;DR: A practical method is given for solving the power flow problem with control variables such as real and reactive power and transformer ratios automatically adjusted to minimize instantaneous costs or losses by Newton's method, a gradient adjustment algorithm for obtaining the minimum and penalty functions to account for dependent constraints.
Abstract: A practical method is given for solving the power flow problem with control variables such as real and reactive power and transformer ratios automatically adjusted to minimize instantaneous costs or losses. The solution is feasible with respect to constraints on control variables and dependent variables such as load voltages, reactive sources, and tie line power angles. The method is based on power flow solution by Newton's method, a gradient adjustment algorithm for obtaining the minimum and penalty functions to account for dependent constraints. A test program solves problems of 500 nodes. Only a small extension of the power flow program is required to implement the method.
1,575 citations
TL;DR: A new technique for solving the differential equations with the implicit trapezoidal rule of integration can be combined into one simultaneous solution, thereby eliminating the problem of interface error between the differential and algebraic equation solutions of the traditional approach.
Abstract: Techniques are described for improving the speed of large transient stability studies without sacrificing accuracy. A fast iterative method for solving the algebraic network equations, including the effect of generator saliency, is explained. A new technique for solving the differential equations with the implicit trapezoidal rule of integration is introduced. These two techniques can be combined into one simultaneous solution, thereby eliminating the problem of interface error between the differential and algebraic equation solutions of the traditional approach.
231 citations
TL;DR: In this paper, a computer-based multiphase harmonic load flow solution technique for analyzing unbalanced load conditions in power systems is described. Butts et al. used static VAr compensators with thyristor-controlled reactors under unbalanced loads to illustrate the method.
Abstract: The operation of nonlinear devices under unbalanced load conditions may cause harmonic problems in power systems. A computer-based multiphase harmonic load flow solution technique for analyzing such problems is described. The harmonic load flows are obtained from iterations between the Norton equivalent circuits of the nonlinear elements and the linear network solutions at harmonic frequencies. Harmonics generated by static VAr compensators with thyristor-controlled reactors under unbalanced load conditions are used to illustrate the method. >
171 citations
TL;DR: The possibility of leveraging the data provided by smart meters to understand the load characteristics is studied and a deterministic framework is proposed that formulates the VVO problem as a mixed-integer quadratically constrained programming problem, which is solved efficiently using advanced branch-and-cut techniques.
Abstract: The possibility of leveraging the data provided by smart meters to understand the load characteristics is studied in this paper. The loads are modeled as voltage-dependent elements to increase the accuracy of volt-VAR optimization (VVO) techniques for distribution systems. VVO techniques are part of the distribution management system and may be used for purposes such as loss reduction, voltage profile improvement, and conservation voltage reduction. A deterministic framework is proposed that formulates the VVO problem as a mixed-integer quadratically constrained programming problem, which is solved efficiently using advanced branch-and-cut techniques. The proposed framework is capable of optimally controlling capacitor banks, voltage regulators, and under-load tap changers (ULTCs) for day-ahead operation planning. The results indicate that loss reductions of up to 40% and a total demand reduction of up to 4.8% are achievable under some loading conditions in a radial test system. The effect of the load voltage dependence is also demonstrated through analytical simulations.
156 citations
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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: In this paper, the authors extend the Dommel-Tinney approach by incorporating exact outage-contingency constraints into the method, to give an optimal steady-state-secure system operating point.
Abstract: The Dommel-Tinney approach to the calculation of optimal power-system load flows has proved to be very powerful and general. This paper extends the problem formulation and solution scheme by incorporating exact outage-contingency constraints into the method, to give an optimal steady-state-secure system operating point. The controllable system quantities in the base-case problem (e.g. generated MW, controlled voltage magnitudes, transformer taps) are optimised within their limits according to some defined objective, so that no limit-violations on other quantities (e. g. generator MVAR and current loadings, transmission-circuit loadings, load-bus voltage magnitudes, angular displacements) occur in either the base-case or contingency-case system operating conditions.
1,487 citations
TL;DR: In this paper, an evolutionary-based approach to solve the optimal power flow (OPF) problem is presented. And the proposed approach has been examined and tested on the standard IEEE 30bus test system with different objectives that reflect fuel cost minimization, voltage profile improvement, and voltage stability enhancement.
1,209 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: An implementation of an interior point method to the optimal reactive dispatch problem is described in this article, which is based on the primal-dual algorithm and the numerical results in large scale networks (1832 and 3467 bus systems) have shown that this technique can be very effective to some optimal power flow applications.
Abstract: An implementation of an interior point method to the optimal reactive dispatch problem is described. The interior point method used is based on the primal-dual algorithm and the numerical results in large scale networks (1832 and 3467 bus systems) have shown that this technique can be very effective to some optimal power flow applications. >
842 citations