Navegando por Autor "TOSTES, Maria Emilia de Lima"

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Análise dos Impactos Harmônicos na Qualidade da Energia Elétrica Utilizando KDD – Estudo de Caso na Universidade Federal do Pará
(Instituto de Tecnologia, 2019) SILVA, Waterloo Ferreira da; TOSTES, Maria Emilia de Lima
This work presents an analysis of data related to Power Quality (PQ), focusing on the significant increase in harmonic distortion levels of current and voltage due to the growing use of non-linear loads and power electronics-based equipment. A methodology was developed using computational intelligence (CI) and data mining techniques to analyze data collected by power quality meters installed at the Federal University of Pará (UFPA). The KDD process was applied, including collection, selection, cleaning, integration, transformation, reduction, mining, interpretation, and evaluation of the data. The Naive Bayes classifier was used in the data mining phase, and the results demonstrated the applicability of the KDD process in the analysis of Total Harmonic Distortion of Voltage at the Common Coupling Point, which can be applied in commercial, residential, and industrial areas.
Barrido de Frecuencia en Coordenadas de Fase para Sistemas Desequilibrados
(INSTITUTO DE TECNOLOGIA, 2012) CABRAL LEITE, Jandeey; TOSTES, Maria Emilia de Lima; PÉREZ ABRIL, Ignacio; MEDEIROS, Adelson Bezerra de; AZEVEDO, Manoel Socorro Santos; BEZERRA, Ubiratan Holanda; MAGALHÃES, Edilson Marques
The paper develops a phase-coordinates model for analyzing unbalanced electrical networks, enabling the specification of single-phase or three-phase harmonic injections of any sequence. The model is applied to a four-wire delta system, demonstrating its ability to represent structural asymmetries and identify resonances at different frequencies.
Optimización Multiobjetivo de Filtros Pasivos
(INSTITUTO DE TECNOLOGIA, 2012) LEITE, Jandecy Cabral; ABRIL, Ignacio Pérez; TOSTES, Maria Emilia de Lima; OLIVEIRA, Roberto Celio Limão de; MAGALHÃES, Edilson Marques
Different approaches have been used to formulate the problem of passive filter design, classified into single or multi-objective formulations. While previous contributions solve the multi-objective problem by minimizing a single objective function composed of a weighted sum of sub-objectives, this work uses the Non-dominated Sorting Genetic Algorithm (NSGA-II) to address the problem. The developed program determines the number, location, configuration, and parameters of passive filters required to obtain non-dominated optimal solutions, considering four predefined filter types. The solution of a practical example demonstrates the effectiveness of the proposed procedure.
Proposta de um algoritmo para diagnosticar a qualidade de energia elétrica utilizando lógica fuzzy
(INSTITUTO DE TECNOLOGIA, 2010) GONÇALVES, Benevaldo Pereira; LEITE, Jandecy Cabral; COSTA JUNIOR, Carlos Tavares da; TOSTES, Maria Emilia de Lima; Eduardo de Magalhães Braga
The article proposes a fuzzy logic-based algorithm to diagnose power quality in low-voltage three-phase systems using the THD (Total Harmonic Distortion) indicator. The fuzzy inference system classifies distortion levels in voltage and current, generating diagnoses such as "normal," "significant," or "critical." The method aims to assist in problem identification and decision-making to mitigate harmonic disturbances, contributing to improved power quality.