Navegando por Assunto "Harmonic distortion"

Agora exibindo 1 - 5 de 5

Acesso aberto (Open Access)
Análise do impacto de conversores de frequência na qualidade da energia do sistema de distribuição de uma indústria de petróleo
(Universidade Federal do Pará, 2010-06-10) MAGALHÃES, Christiane Marques Sousa de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
In this work, it is presented an analysis of the distribution system power quality of an oil industry in order to evaluate the impact of the installation of frequency converters regarding the harmonic distortion. The harmonic distortion data were collected through two measurements over a period of seven consecutive days, one performed before and other after the installation of frequency converters. Additionally, a computational study using PTW (Power Tools for Windows) is presented in order to simulate future conditions of new frequency converters installation and to analyse the influence of capacitor banks in the amplification of distribution system harmonic distortion.
Acesso aberto (Open Access)
Avaliação da distorção harmônica total de tensão no ponto de acoplamento comum industrial usando o processo KDD baseado em medição
(Universidade Federal do Pará, 2018-03-27) OLIVEIRA, Edson Farias de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
In the last decades, the transformation industry has provided the introduction of increasingly faster and more energy efficient products for residential, commercial and industrial use, however these loads due to their non-linearity have contributed significantly to the increase of distortion levels harmonic of voltage as a result of the current according to the Power Quality indicators of the Brazilian electricity distribution system. The constant increase in the levels of distortions, especially at the point of common coupling, has generated in the current day a lot of concern in the concessionaires and in the consumers of electric power, due to the problems that cause like losses of the quality of electric power in the supply and in the installations of the consumers and this has provided several studies on the subject. In order to contribute to the subject, this thesis proposes a procedure based on the Knowledge Discovery in Database - KDD process to identify the impact loads of harmonic distortions of voltage at the common coupling point. The proposed methodology uses computational intelligence and data mining techniques to analyze the data collected by energy quality meters installed in the main loads and the common coupling point of the consumer and consequently establish the correlation between the harmonic currents of the nonlinear loads with the harmonic distortion at the common coupling point. The proposed process consists in analyzing the loads and the layout of the location where the methodology will be applied, in the choice and installation of the QEE meters and in the application of the complete KDD process, including the procedures for collection, selection, cleaning, integration, transformation and reduction, mining, interpretation, and evaluation of data. In order to contribute, the data mining techniques of Decision Tree and Naïve Bayes were applied and several algorithms were tested for the algorithm with the most significant results for this type of analysis as presented in the results. The results obtained evidenced that the KDD process has applicability in the analysis of the Voltage Total Harmonic Distortion at the Point of Common Coupling and leaves as contribution the complete description of each step of this process, and for this it was compared with different indices of data balancing, training and test and different scenarios in different shifts of analysis and presented good performance allowing their application in other types of consumers and energy distribution companies. It also shows, in the chosen application and using different scenarios, that the most impacting load was the seventh current harmonic of the air conditioning units for the collected data set.
Acesso aberto (Open Access)
Estimação da contribuição de múltiplas fontes harmônicas utilizando regressão não paramétrica
(Universidade Federal do Pará, 2012-03-22) SOARES, Thiago Mota; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
This paper presents a new methodology for estimating the contribution of multiple harmonic-producing loads in the voltage harmonic distortion in an electrical system. This method creates statistical models that describe the behavior of the harmonic voltage of an electrical system in function of the harmonic current of the loads present in the system so that it is possible to evaluate the impact of harmonic-producing loads in the levels of harmonic voltage in the electrical system under consideration. The creation of these models is performed based on the statistical method called local polynomial kernel regression, which is a nonparametric regression method, whose main feature is to create models not conditional on a specific family of regression curves, that is, data are solely responsible for the shape of the model. Once the model is created, it is estimated the harmonic voltage caused by the loads in the period under consideration, and, finally, this voltage is evaluated in relation to the harmonic voltage measured.
Acesso aberto (Open Access)
Impactos na qualidade da energia elétrica provenientes do rápido crescimento da demanda no Sudeste do Estado do Pará
(Universidade Federal do Pará, 2012-03-15) ESTEVES, Eduardo Augusto Cardoso; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
In the recent years, the social and economical development in the Southeast of the State of Pará has been mainly caused by the exploitation and processing of mineral industries, which added to the population growth, has generated a high increase in the demand of electric energy and consumption due to the increasing installation of new industrial, commercial, residential and rural single-phase charges. This global increase is impacting directly the performance of distribution of electric utility, which can be expressed by the permanent disturbances caused by harmonics, such as buzzing in the power transformer and disruption of medium voltage conductors. These disturbances will be presented in a study of case involving the Substations (SE’s) Itacaiúna and Itupiranga. To prove how they can be harmful in these SE’s, campaigns of measurement were performed to obtain practical results and then, to perform studies involving simulations of short-circuit, load flow and spreading of harmonics in order to obtain an analytical diagnostic about the situations found and thus to issue recommendations to solve the problems identified. This study will provide a valuable support to the Concessionaire of Energy and it may be taken as a reference to the study of Power Quality in other substations, in addition to experimental basis for future charges from ANEEL, regarding the implementation of procedures in Electric Power Distribution National Electric System (PRODIST).
Acesso aberto (Open Access)
Previsão de distorção harmônica em cargas residenciais utilizando redes neuro-fuzzy
(Universidade Federal do Pará, 2018-07-11) MORAIS JÚNIOR, Albino Moisés Faro de; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
This work presents a modeling for THDv%, THDi% and individual harmonics using predictions from an ANFIS system that learns with measured data and predicts the behavior of the network for future values. These forecasts can help meet national THDv% standards stipulated by the Agência Nacional de Energia Elétrica (ANEEL) through Distribution Procedures (PRODIST), such as THDi% international standards, thus anticipating the currently recommended standards, but in the near future will be punitive. The modeling is performed by means of a Neuro-Fuzzy system called ANFIS, which uses neural network to learn the behavior of the system and adjustment of the parameters and Fuzzy rule for the determination of the system output values taking into account the learning of the Neural network. The great advantage of this tool is the power of modeling standards using a prediction of the harmonic state of the connected loads in the low voltage, which helps in the creation of pseudomedidas for the distribution networks, where it is difficult and costly to obtain real measurements. Among the practical applications for this tool is the use of the predicted values instead of measured anomalous values, the use in energy meters to predict and avoid exceeding the values of Harmonic Distortion stipulated in standard and the use as a basis for the prediction of individual harmonics that can be used in harmonic load flow studies.