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Your search keyword '"Alberto, Luis F. C."' showing total 87 results
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87 results on '"Alberto, Luis F. C."'

1. Combining Trajectory Data with Analytical Lyapunov Functions for Improved Region of Attraction Estimation

Author

Lugnani, Lucas, Jones, Morgan, Alberto, Luís F. C., Peet, Mathew, and Dotta, Daniel

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

The increasing uptake of inverter based resources (IBRs) has resulted in many new challenges for power system operators around the world. The high level of complexity of IBR generators makes accurate classical model-based stability analysis a difficult task. This paper proposes a novel methodology for solving the problem of estimating the Region of Attraction (ROA) of a nonlinear system by combining classical model based methods with modern data driven methods. Our method yields certifiable inner approximations of the ROA, typical to that of model based methods, but also harnesses trajectory data to yield an improved accurate ROA estimation. The method is carried out by using analytical Lyapunov functions, such as energy functions, in combination with data that is used to fit a converse Lyapunov function. Our methodology is independent of the function fitting method used. In this work, for implementation purposes, we use Bernstein polynomials to function fit. Several numerical examples of ROA estimation are provided, including the Single Machine Infinite Bus (SMIB) system, a three machine system and the Van-der-Pol system., Comment: 6 pages, 4 figures

Published
2021

2. Parameter Reduction in Probabilistic Critical Time Evaluation Using Sensitivity Analysis and PCA

Author

Fortulan, Raphael L. V. and Alberto, Luís F. C.

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

In this paper, we discuss a method to find the most influential power system parameters to the probabilistic transient stability assessment problem---finding the probability distribution of the critical clearing time. We perform the parameter selection by employing a sensitivity analysis combined with a principal component analysis. First, we determine the sensitivity of the machine angles with respect to all system parameters. Second, we employ the principal component analysis algorithm to identify the most influential parameters in the transient stability problem. By identifying such parameters, we can reduce the number of uncertain parameters to only the influential ones in the probabilistic assessment of transient stability, providing a significant speed-up in the probabilistic analysis of large power systems. The proposed algorithm was tested in the IEEE 14 bus systems and the results obtained show that our method can effectively find the most influential parameters., Comment: 5 pages

Published
2020

4. Bifurcations and Stability Regions of Nonlinear Dynamical Systems

Author

Alberto, Luis F. C., Amaral, Fabiolo M., Gouveia Jr., Josaphat R. R., Abarbanel, Henry D.I., Series editor, Braha, Dan, Series editor, Érdi, Péter, Series editor, Friston, Karl J, Series editor, Haken, Hermann, Series editor, Jirsa, Viktor, Series editor, Kacprzyk, Janusz, Series editor, Kaneko, Kunihiko, Series editor, Kelso, Scott, Series editor, Kirkilionis, Markus, Series editor, Kurths, Jürgen, Series editor, Menezes, Ronaldo, Series editor, Nowak, Andrzej, Series editor, Qudrat-Ullah, Hassan, Series editor, Reichl, Linda, Series editor, Schuster, Peter, Series editor, Schweitzer, Frank, Series editor, Sornette, Didier, Series editor, Thurner, Stefan, Series editor, Edelman, Mark, editor, Macau, Elbert E. N., editor, and Sanjuan, Miguel A. F., editor

Published
2018
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5. A Generalized Harmonic Injection Analysis Aimed at Improving Power Transfer

Author

Volpato, Alvaro A., Alberto, Luis F. C., and Machado, Ricardo Q.

Abstract

Harmonic Injection is a technique often used in Electric Power Systems for harmonic compensation control in distributed power plants and for optimizing power transfer and modulation distortion in switched-mode devices, among other applications. This brief presents a thorough mathematical investigation of the harmonic injection technique, generalizing the well-known third-order harmonic injection analysis to the problem of n-th order harmonic injection, and answering two open questions in the current literature: why is the third harmonic the only one used, and why are the even-order harmonics never contemplated?

Published
2024
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6. Integrating Hierarchical Clustering and Pareto-Efficiency to Preventive Controls Selection in Voltage Stability Assessment

Author

Mansour, Moussa R., Delbem, Alexandre C. B., Alberto, Luis F. C., Ramos, Rodrigo A., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Gaspar-Cunha, António, editor, Henggeler Antunes, Carlos, editor, and Coello, Carlos Coello, editor

Published
2015
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9. Application of Melnikov's Method for Computing Heteroclinic Orbits in a Classical SMIB Power System Model

Author

Alberto, Luis F. C. and Bretas, Newton G.

Subjects
Damping (Mechanics) -- Research, Power (Mechanics) -- Research, Transients (Electricity) -- Analysis, Hydrothermal electric power systems -- Models, Business, Computers and office automation industries, Electronics, Electronics and electrical industries
Abstract

The main concern of this paper is the application of the Meinikov method for computing heteroclinic orbits in a classical SMIB power system model and testing the one-parameter transversality condition required in the BCU method for transient stability analysis. First, the Melnikov method is used to give a first approximation for the minimum damping coefficient or, alternatively, for the maximum input mechanical power that should be associated with the system so that the transversality condition is satisfied. This first approximation is obtained without solving any differential equations. After that, this approximation is used as an initial condition for a monotonically convergent process which is very easy to implement and does not require knowledge of fault trajectory at all. Index Terms--Damping estimation, energy methods, transient stability analysis.

Published
2000

10. On the Invariance Principle: Generalizations and Applications to Synchronization

Author

Rodrigues, Hildebrando M., Alberto, Luis F. C., and Bretas, Newton G.

Subjects
Symmetry (Physics) -- Research, Business, Computers and office automation industries, Electronics, Electronics and electrical industries
Abstract

In many engineering and physics problems it is very hard to find a Liapunov function satisfying the classical version of the LaSalle's invariance principle. In this work, an extension of the invariance principle, which includes cases where the derivative of the Liapunov function along the solutions is positive on a bounded set, is given. As a consequence, a larger class of problems may now be considered. The results are used to obtain estimates of attractors which are independent of coupling parameters. They are also applied to study the synchronization of coupled systems, such as coupled power systems and coupled Lorenz systems. Estimates on the coupling term are obtained in order to accomplish the synchronization. Index Terms--Attractor, dissipativeness, invariance principle, stability of manifold of solutions, synchronization, ultimate boundedness.

Published
2000

18. A comparative validation of a synchronous generator by trajectory sensitivity and offline methods.

Author

Beordo, Lucas, Cari, Elmer P. T., Landgraf, Taylon G., and Alberto, Luis F. C.

Subjects
SYNCHRONOUS generators, SHORT circuits, ELECTRIC potential measurement, COMPARATIVE studies, ALGEBRAIC equations, STEADY state conduction
Abstract

This paper addresses a comparison between online and offline methods to estimate parameters of a synchronous generator. The main aim of this comparison is to validate the results of a new online method based on trajectory sensitivity method against offline method. Steady-state, sudden short circuit, and voltage recovery tests were selected among the offline methods to serve of comparison for trajectory sensitivity method. The online method has the following features: It uses only terminal voltages and currents and field voltage measurements, it does not need the power angle, and it estimates the power angle using an auxiliary algebraic equation. Tests were conducted in a 2-kVA salient pole machine, and the differences in parameter values obtained from each approaches were analyzed. Eventually, it is concluded that technique based on trajectory sensitivity provides more reliable generator parameters of estimation process. [ABSTRACT FROM AUTHOR]

Published
2017
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