Emília Tostes - Academia.edu (original) (raw)

Papers by Emília Tostes

Research paper thumbnail of Virtual Modeling and Experimental Validation of the Line-Start Permanent Magnet Motor in the Presence of Harmonics

Energies

The world is experiencing an accelerated energy transition that is driven by the climate goals to... more The world is experiencing an accelerated energy transition that is driven by the climate goals to be met and that has driven the growth of different potential sectors such as electric mobility powered by electric motors, which continue to be the largest load globally. However, new needs in relation to power density, weight, and efficiency have led manufacturers to experiment with new technologies, such as rare earth elements (REEs). The permanent magnet motor is a candidate to be the substitute for the conventional induction motor considering the new editions of the IEC 60034-30-1, for which study and evaluation continue to be focused on identifying the weaknesses and benefits of its application on a large scale in industry and electric mobility. This work presents a FEM model to assess the line-start permanent magnet motor (LSPMM), aiming to simulate the behavior of the LSPMM under supply conditions with distorted voltages (harmonic content) and evaluate its thermal and magnetic pe...

Research paper thumbnail of Análise e Soluções Para a Qualidade Da Rede De Energia Elétrica Da Ufpa

Revista Contemporânea

Este artigo apresenta uma análise da rede elétrica do campus Guamá da Universidade Federal do Par... more Este artigo apresenta uma análise da rede elétrica do campus Guamá da Universidade Federal do Pará com o objetivo de corrigir o baixo fator de potência que a universidade vem enfrentando desde 2017 e foi agravado pela pandemia de COVID-19. A contribuição deste trabalho é dimensionar um banco de capacitores para realizar a compensação de reativo no campus e consequentemente diminuir as multas referentes ao excedente de reativo.

Research paper thumbnail of Harmonic Effects Due to the High Penetration of Photovoltaic Generation into a Distribution System

Energies

The growth in global electricity demand has expanded the search for new energy resources. Renewab... more The growth in global electricity demand has expanded the search for new energy resources. Renewable sources such as photovoltaic (PV) systems have proven to be major alternatives. PV generators connected to distribution grids have exhibited significant growth in the last decade, so it is essential to analyse the impacts resulting from this increase. This work investigated the influence of high PV system penetration in distribution grids in terms of harmonic levels. In particular, this study addressed the distortions in voltage and current waveforms in the presence and absence of PV generators connected to a distribution grid. Additionally, the total harmonic content and the individual harmonic frequencies of voltage and current were analysed. This study was performed with an IEEE 37 bus distribution system and the Open Distribution System Simulator software (OpenDSS). The results show that the voltage limits of some phases far away from a substation can exceed the limits. Furthermor...

Research paper thumbnail of Ten Years of Minimum Efficiency Standards for Induction Motors in Brazil: From Standards Class until Super Premium Motors

Research paper thumbnail of Implementação de um cluster Kubernetes com a plataforma Dojot para Aplicações de Internet das Coisas

Anais do XLVIII Seminário Integrado de Software e Hardware (SEMISH 2021), 2021

A técnica de virtualização baseadas em contêineres vem sendo amplamente utilizada através da adoç... more A técnica de virtualização baseadas em contêineres vem sendo amplamente utilizada através da adoção de tecnologias como Docker e Kubernetes que permitem a criação e o gerenciamento de contêineres. Assim, o presente artigo utilizou o Prometheus e o Grafana para analisar a performance de um cluster Kubernetes executando a plataforma Dojot e recebendo dados de um simulador. Foi possível observar que o uso dos recursos de CPU e memória RAM são maiores nas máquinas Workers do cluster, onde quanto mais serviços da Dojot a máquina executa maior o consumo dos recursos. Concluiu-se que a utilização do Kubernetes juntamente com os seus recursos de gerenciamento e monitoramento são recomendáveis para aplicações que precisam se escaláveis.

Research paper thumbnail of Modelagem de um sistema de distribuição real desbalanceado e análise do impacto da geração distribuída utilizando o software OpenDSS

Anais do Simpósio Brasileiro de Sistemas Elétricos 2020, 2020

O presente trabalho utiliza o software OpenDSS para modelar uma rede elétrica de distribuição, ca... more O presente trabalho utiliza o software OpenDSS para modelar uma rede elétrica de distribuição, capaz de simular o comportamento da rede elétrica e os impactos na qualidade de energia elétrica de acordo com as diferentes topologias de transformadores, cargas e fontes de geração distribuída em que uma rede elétrica pode ser submetida. Como estudo de caso, o artigo utiliza dados reais da rede da Universidade Federal do Pará e a inserção de geradores solar fotovoltaicos em diferentes pontos da rede, como demonstração do impacto na redução da potência ativa, na elevação do nível de tensão e na redução de perdas elétricas de acordo com a inserção da geração distribuída (GD) na rede elétrica estudada.

Research paper thumbnail of Smart City: application of the ABNT NBR ISO 37122:2020 Standard in the University City of UFPA

2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021

In recent years, some research and development (R&D) companies in the energy area have been d... more In recent years, some research and development (R&D) companies in the energy area have been developed by the Federal University of Pará (UFPA) within the University City Campus Professor José Silveira Netto. These projects have included elements of a Smart City on the Campus. However, there is still no survey to identify which indicators of a smart city are already present on the Campus and how smart it is. Therefore, this article will present the application of the Brazilian Standard ABNT NBR ISO 37122: 2020 of Smart Cities Indicators at the UFPA Headquarters Campus, with the objective of verifying which Smart City indicators are already present on the Campus due to the development of an electric mobility R&D. In addition to being the first time this standard has been applied on Campus, this work is also the first to carry out such a survey. As a result, a checklist was generated, where it was possible to count 4 categories and 17 indicators present within the Campus. Thus, demonstrating that UFPA is starting its process of insertion in the concept of Smart Cities.

Research paper thumbnail of Assessing Voltage Unbalance Conditions in IE2, IE3 and IE4 Classes Induction Motors

IEEE Access, 2020

Brazil has started an energy transition process through more efficient electric motors. The new l... more Brazil has started an energy transition process through more efficient electric motors. The new legislation determining the IE3 Class as the minimum efficiency level in commercial electric motors became valid in August 2019. Currently, four induction motor classes are defined by the IEC 60034-30-1, with the IE4 class being the most efficient, and in the same way, proposals to achieve IE5 efficiency class are available in the market. Considering the upcoming new technologies, it is necessary to know the impact of power systems disturbances in IM's in view of future substitutions. This paper presents a detailed analysis of the impact of different percentages of under and over voltage unbalances on the temperature and performance of electric motors classes IE2, IE3 and IE4. Results show that the IE4 hybrid motor presents non-linear characteristics, being observed this motor shows less dependence on voltage variation, mainly undervoltage unbalance. An analysis of how this phenomenon impacts on the current harmonic distortions in the induction motors operation is also developed through Spearman's correlation matrices. Finally, models that represent the temperature increase of each motor with different voltage unbalance conditions are presented.

Research paper thumbnail of Análise e Solução para Baixo Fator de Potência na Rede de Distribuição da UFPA em Tempos de Pandemia

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Estimativa de impacto na fatura de energia em um prédio comercial utilizando sistemas fotovoltaicos e banco de baterias

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Influência da Operação de um Sistema de Armazenamento a Bateria na Qualidade da Energia

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Análise de Engenharia Ex-Ante aplicada a uma Edificação com Operação em Horário de Ponta

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Voltage Harmonic Impacts on Electric Motors: A Comparison between IE2, IE3 and IE4 Induction Motor Classes

Energies, 2020

Global energy systems are undergoing a transition process towards renewable energy and energy eff... more Global energy systems are undergoing a transition process towards renewable energy and energy efficiency practices. Induction motors play an important role in this energy transformation process since they are widely used as industrial loads, representing more than 53% of global energy consumption. With more countries adopting minimum energy performance standards through more efficient induction motors, comparisons between these new technologies in the presence of electrical disturbances must be systematically evaluated before adopting a substitution policy in the industry. To this end, this work presents a comparative analysis of the impact of harmonic voltages on the performance and temperature rise of electric motors classes IE2, IE3 and IE4 in the same operational conditions in view of future substitutions. The results show that under ideal operating conditions the IE4 class permanent magnet motor has better performance in terms of consumption and temperature, however presenting ...

Research paper thumbnail of Voltage THD Analysis Using Knowledge Discovery in Databases With a Decision Tree Classifier

IEEE Access, 2018

Industrial production has evolved significantly over the last decade. For this reason, it is nece... more Industrial production has evolved significantly over the last decade. For this reason, it is necessary to obtain mathematical and computational tools that enable power systems engineers to make decisions that reduce harmonic distortions in accordance with international standards. This paper presents a total harmonic distortion (THD) assessment based on full knowledge discovery in databases (KDD) using power quality (PQ) standards and computational intelligence tools. The materials and methods of THD assessment consist of load and layout analysis; choice and installation of PQ analyzers; and the application of the full KDD process, including collection, selection, cleaning, integration, transformation and reduction, mining, interpretation, and evaluation of the data. This research methodology was used in an electrical and electronic industry; the results obtained have characteristics that can be used as a reference for other types of analyses. The results indicate that these methods can be applied to several industrial applications such as: 1) the description of the complete KDD process for THD assessment of the point of common coupling; 2) simultaneous collection using five PQ analyzers at several points in the electrical network; and (3) the use of a decision tree classifier.

Research paper thumbnail of Methodology for Preliminary Design of Buildings Using Multi-Objective Optimization Based on Performance Simulation

Journal of Solar Energy Engineering, 2019

Buildings' energy consumption has a great energetic and environmental impact worldwide. The a... more Buildings' energy consumption has a great energetic and environmental impact worldwide. The architectural design has great potential to solve this problem because the building envelope exerts influence on the overall system performance, but this is a task that involves many objectives and constraints. In the last two decades, optimization studies applied to energy efficiency of buildings have helped specialists to choose the best design options. However, there is still a lack of optimization approaches applied to the design stage, which is the most influential stage for building energy efficiency over its entire life cycle. Therefore, this article presents a multi-objective optimization model to assist designers in the schematic building design, by means of the Pareto archived evolutionary strategies (PAES) algorithm with the EnergyPlus simulator coupled to evaluate the solutions. The search process is executed by a binary array where the array components evolve over the generat...

Research paper thumbnail of Evaluating Harmonic Distortions on Grid Voltages Due to Multiple Nonlinear Loads Using Artificial Neural Networks

Energies, 2018

This paper presents a procedure to estimate the impacts on voltage harmonic distortion at a point... more This paper presents a procedure to estimate the impacts on voltage harmonic distortion at a point of interest due to multiple nonlinear loads in the electrical network. Despite artificial neural networks (ANN) being a widely used technique for the solution of a large amount and variety of issues in electric power systems, including harmonics modeling, its utilization to establish relationships among the harmonic voltage at a point of interest in the electric grid and the corresponding harmonic currents generated by nonlinear loads was not found in the literature, thus this innovative procedure is considered in this article. A simultaneous measurement campaign must be carried out in all nonlinear loads and at the point of interest for data acquisition to train and test the ANN model. A sensitivity analysis is proposed to establish the percent contribution of load currents on the observed voltage distortion, which constitutes an original definition presented in this paper. Initially, ...

Research paper thumbnail of Evaluation of the Harmonic Impact in an Electrical System Using Polynomial-Regression Method

Renewable Energy and Power Quality Journal, 2012

This paper presents a method to determine the individual harmonic influence of multiple harmonic-... more This paper presents a method to determine the individual harmonic influence of multiple harmonic-producing loads in an electrical power system. This method is based in the development of statistical models from measurement data using the polynomial-regression technique. A real case study is presented in order to show the performance of the proposed method.

Research paper thumbnail of Análise da Eficiência Energética com o Uso do RETScreen Considerando Implementação de Iluminação a LED no Complexo Predial da SUDAM

Anais do VI Simpósio Brasileiro de Sistemas Elétricos, 2015

Research paper thumbnail of Allocation and Sizing of Dispersed Photovoltaic Generation in Diesel Isolated Electrical Systems Using an Analytical Approach

Journal of Solar Energy Engineering, 2014

This paper proposes an analytical methodology to allocate and size active power photovoltaic gene... more This paper proposes an analytical methodology to allocate and size active power photovoltaic generation (PVG) units with embedded DC/AC inverter (PVGI) to be integrated as concentrated or dispersed generation in isolated medium voltage electrical grids. The methodology considers multiple objectives: improving the electrical grid voltage profile; reducing active power losses and the diesel generation participation. To validate the proposed methodology, the IEEE 33 and 69 buses networks and an isolated real electrical system were simulated. The results obtained demonstrated that the proposed methodology is effective in providing a solution with improvement in voltage profile, active power losses reduction, diesel generation participation reduction.

Research paper thumbnail of Evolution of the passive harmonic filters optimization problem in industrial power systems

DYNA, 2014

Several authors have treated the optimization of passive filters in electric distribution systems... more Several authors have treated the optimization of passive filters in electric distribution systems. Optimization methods like: sequential quadratic programming (SQP), simulated annealing (SA), differential evolution (DE), artificial neural networks (ANN), particle swarm optimization (PSO), genetic algorithm (GA), etc., have been employed for optimizing certain configurations of passive filters. These optimization methods have been employed to solve several formulations of the problem of the project of filters. These formulations can be classified in: formulations of one or several objectives. The objective of the present work is to show the evolution of the formulation of this problem in the lasts years respect to the objective functions and constraints used. This analysis shows how the formulations employed have been upgraded from single-objective to multi-objective formulations to achieve a better representation of this complex problem.

Research paper thumbnail of Virtual Modeling and Experimental Validation of the Line-Start Permanent Magnet Motor in the Presence of Harmonics

Energies

The world is experiencing an accelerated energy transition that is driven by the climate goals to... more The world is experiencing an accelerated energy transition that is driven by the climate goals to be met and that has driven the growth of different potential sectors such as electric mobility powered by electric motors, which continue to be the largest load globally. However, new needs in relation to power density, weight, and efficiency have led manufacturers to experiment with new technologies, such as rare earth elements (REEs). The permanent magnet motor is a candidate to be the substitute for the conventional induction motor considering the new editions of the IEC 60034-30-1, for which study and evaluation continue to be focused on identifying the weaknesses and benefits of its application on a large scale in industry and electric mobility. This work presents a FEM model to assess the line-start permanent magnet motor (LSPMM), aiming to simulate the behavior of the LSPMM under supply conditions with distorted voltages (harmonic content) and evaluate its thermal and magnetic pe...

Research paper thumbnail of Análise e Soluções Para a Qualidade Da Rede De Energia Elétrica Da Ufpa

Revista Contemporânea

Este artigo apresenta uma análise da rede elétrica do campus Guamá da Universidade Federal do Par... more Este artigo apresenta uma análise da rede elétrica do campus Guamá da Universidade Federal do Pará com o objetivo de corrigir o baixo fator de potência que a universidade vem enfrentando desde 2017 e foi agravado pela pandemia de COVID-19. A contribuição deste trabalho é dimensionar um banco de capacitores para realizar a compensação de reativo no campus e consequentemente diminuir as multas referentes ao excedente de reativo.

Research paper thumbnail of Harmonic Effects Due to the High Penetration of Photovoltaic Generation into a Distribution System

Energies

The growth in global electricity demand has expanded the search for new energy resources. Renewab... more The growth in global electricity demand has expanded the search for new energy resources. Renewable sources such as photovoltaic (PV) systems have proven to be major alternatives. PV generators connected to distribution grids have exhibited significant growth in the last decade, so it is essential to analyse the impacts resulting from this increase. This work investigated the influence of high PV system penetration in distribution grids in terms of harmonic levels. In particular, this study addressed the distortions in voltage and current waveforms in the presence and absence of PV generators connected to a distribution grid. Additionally, the total harmonic content and the individual harmonic frequencies of voltage and current were analysed. This study was performed with an IEEE 37 bus distribution system and the Open Distribution System Simulator software (OpenDSS). The results show that the voltage limits of some phases far away from a substation can exceed the limits. Furthermor...

Research paper thumbnail of Ten Years of Minimum Efficiency Standards for Induction Motors in Brazil: From Standards Class until Super Premium Motors

Research paper thumbnail of Implementação de um cluster Kubernetes com a plataforma Dojot para Aplicações de Internet das Coisas

Anais do XLVIII Seminário Integrado de Software e Hardware (SEMISH 2021), 2021

A técnica de virtualização baseadas em contêineres vem sendo amplamente utilizada através da adoç... more A técnica de virtualização baseadas em contêineres vem sendo amplamente utilizada através da adoção de tecnologias como Docker e Kubernetes que permitem a criação e o gerenciamento de contêineres. Assim, o presente artigo utilizou o Prometheus e o Grafana para analisar a performance de um cluster Kubernetes executando a plataforma Dojot e recebendo dados de um simulador. Foi possível observar que o uso dos recursos de CPU e memória RAM são maiores nas máquinas Workers do cluster, onde quanto mais serviços da Dojot a máquina executa maior o consumo dos recursos. Concluiu-se que a utilização do Kubernetes juntamente com os seus recursos de gerenciamento e monitoramento são recomendáveis para aplicações que precisam se escaláveis.

Research paper thumbnail of Modelagem de um sistema de distribuição real desbalanceado e análise do impacto da geração distribuída utilizando o software OpenDSS

Anais do Simpósio Brasileiro de Sistemas Elétricos 2020, 2020

O presente trabalho utiliza o software OpenDSS para modelar uma rede elétrica de distribuição, ca... more O presente trabalho utiliza o software OpenDSS para modelar uma rede elétrica de distribuição, capaz de simular o comportamento da rede elétrica e os impactos na qualidade de energia elétrica de acordo com as diferentes topologias de transformadores, cargas e fontes de geração distribuída em que uma rede elétrica pode ser submetida. Como estudo de caso, o artigo utiliza dados reais da rede da Universidade Federal do Pará e a inserção de geradores solar fotovoltaicos em diferentes pontos da rede, como demonstração do impacto na redução da potência ativa, na elevação do nível de tensão e na redução de perdas elétricas de acordo com a inserção da geração distribuída (GD) na rede elétrica estudada.

Research paper thumbnail of Smart City: application of the ABNT NBR ISO 37122:2020 Standard in the University City of UFPA

2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021

In recent years, some research and development (R&D) companies in the energy area have been d... more In recent years, some research and development (R&D) companies in the energy area have been developed by the Federal University of Pará (UFPA) within the University City Campus Professor José Silveira Netto. These projects have included elements of a Smart City on the Campus. However, there is still no survey to identify which indicators of a smart city are already present on the Campus and how smart it is. Therefore, this article will present the application of the Brazilian Standard ABNT NBR ISO 37122: 2020 of Smart Cities Indicators at the UFPA Headquarters Campus, with the objective of verifying which Smart City indicators are already present on the Campus due to the development of an electric mobility R&D. In addition to being the first time this standard has been applied on Campus, this work is also the first to carry out such a survey. As a result, a checklist was generated, where it was possible to count 4 categories and 17 indicators present within the Campus. Thus, demonstrating that UFPA is starting its process of insertion in the concept of Smart Cities.

Research paper thumbnail of Assessing Voltage Unbalance Conditions in IE2, IE3 and IE4 Classes Induction Motors

IEEE Access, 2020

Brazil has started an energy transition process through more efficient electric motors. The new l... more Brazil has started an energy transition process through more efficient electric motors. The new legislation determining the IE3 Class as the minimum efficiency level in commercial electric motors became valid in August 2019. Currently, four induction motor classes are defined by the IEC 60034-30-1, with the IE4 class being the most efficient, and in the same way, proposals to achieve IE5 efficiency class are available in the market. Considering the upcoming new technologies, it is necessary to know the impact of power systems disturbances in IM's in view of future substitutions. This paper presents a detailed analysis of the impact of different percentages of under and over voltage unbalances on the temperature and performance of electric motors classes IE2, IE3 and IE4. Results show that the IE4 hybrid motor presents non-linear characteristics, being observed this motor shows less dependence on voltage variation, mainly undervoltage unbalance. An analysis of how this phenomenon impacts on the current harmonic distortions in the induction motors operation is also developed through Spearman's correlation matrices. Finally, models that represent the temperature increase of each motor with different voltage unbalance conditions are presented.

Research paper thumbnail of Análise e Solução para Baixo Fator de Potência na Rede de Distribuição da UFPA em Tempos de Pandemia

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Estimativa de impacto na fatura de energia em um prédio comercial utilizando sistemas fotovoltaicos e banco de baterias

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Influência da Operação de um Sistema de Armazenamento a Bateria na Qualidade da Energia

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Análise de Engenharia Ex-Ante aplicada a uma Edificação com Operação em Horário de Ponta

Anais da XIV Conferência Brasileira sobre Qualidade da Energia Elétrica, 2021

Research paper thumbnail of Voltage Harmonic Impacts on Electric Motors: A Comparison between IE2, IE3 and IE4 Induction Motor Classes

Energies, 2020

Global energy systems are undergoing a transition process towards renewable energy and energy eff... more Global energy systems are undergoing a transition process towards renewable energy and energy efficiency practices. Induction motors play an important role in this energy transformation process since they are widely used as industrial loads, representing more than 53% of global energy consumption. With more countries adopting minimum energy performance standards through more efficient induction motors, comparisons between these new technologies in the presence of electrical disturbances must be systematically evaluated before adopting a substitution policy in the industry. To this end, this work presents a comparative analysis of the impact of harmonic voltages on the performance and temperature rise of electric motors classes IE2, IE3 and IE4 in the same operational conditions in view of future substitutions. The results show that under ideal operating conditions the IE4 class permanent magnet motor has better performance in terms of consumption and temperature, however presenting ...

Research paper thumbnail of Voltage THD Analysis Using Knowledge Discovery in Databases With a Decision Tree Classifier

IEEE Access, 2018

Industrial production has evolved significantly over the last decade. For this reason, it is nece... more Industrial production has evolved significantly over the last decade. For this reason, it is necessary to obtain mathematical and computational tools that enable power systems engineers to make decisions that reduce harmonic distortions in accordance with international standards. This paper presents a total harmonic distortion (THD) assessment based on full knowledge discovery in databases (KDD) using power quality (PQ) standards and computational intelligence tools. The materials and methods of THD assessment consist of load and layout analysis; choice and installation of PQ analyzers; and the application of the full KDD process, including collection, selection, cleaning, integration, transformation and reduction, mining, interpretation, and evaluation of the data. This research methodology was used in an electrical and electronic industry; the results obtained have characteristics that can be used as a reference for other types of analyses. The results indicate that these methods can be applied to several industrial applications such as: 1) the description of the complete KDD process for THD assessment of the point of common coupling; 2) simultaneous collection using five PQ analyzers at several points in the electrical network; and (3) the use of a decision tree classifier.

Research paper thumbnail of Methodology for Preliminary Design of Buildings Using Multi-Objective Optimization Based on Performance Simulation

Journal of Solar Energy Engineering, 2019

Buildings' energy consumption has a great energetic and environmental impact worldwide. The a... more Buildings' energy consumption has a great energetic and environmental impact worldwide. The architectural design has great potential to solve this problem because the building envelope exerts influence on the overall system performance, but this is a task that involves many objectives and constraints. In the last two decades, optimization studies applied to energy efficiency of buildings have helped specialists to choose the best design options. However, there is still a lack of optimization approaches applied to the design stage, which is the most influential stage for building energy efficiency over its entire life cycle. Therefore, this article presents a multi-objective optimization model to assist designers in the schematic building design, by means of the Pareto archived evolutionary strategies (PAES) algorithm with the EnergyPlus simulator coupled to evaluate the solutions. The search process is executed by a binary array where the array components evolve over the generat...

Research paper thumbnail of Evaluating Harmonic Distortions on Grid Voltages Due to Multiple Nonlinear Loads Using Artificial Neural Networks

Energies, 2018

This paper presents a procedure to estimate the impacts on voltage harmonic distortion at a point... more This paper presents a procedure to estimate the impacts on voltage harmonic distortion at a point of interest due to multiple nonlinear loads in the electrical network. Despite artificial neural networks (ANN) being a widely used technique for the solution of a large amount and variety of issues in electric power systems, including harmonics modeling, its utilization to establish relationships among the harmonic voltage at a point of interest in the electric grid and the corresponding harmonic currents generated by nonlinear loads was not found in the literature, thus this innovative procedure is considered in this article. A simultaneous measurement campaign must be carried out in all nonlinear loads and at the point of interest for data acquisition to train and test the ANN model. A sensitivity analysis is proposed to establish the percent contribution of load currents on the observed voltage distortion, which constitutes an original definition presented in this paper. Initially, ...

Research paper thumbnail of Evaluation of the Harmonic Impact in an Electrical System Using Polynomial-Regression Method

Renewable Energy and Power Quality Journal, 2012

This paper presents a method to determine the individual harmonic influence of multiple harmonic-... more This paper presents a method to determine the individual harmonic influence of multiple harmonic-producing loads in an electrical power system. This method is based in the development of statistical models from measurement data using the polynomial-regression technique. A real case study is presented in order to show the performance of the proposed method.

Research paper thumbnail of Análise da Eficiência Energética com o Uso do RETScreen Considerando Implementação de Iluminação a LED no Complexo Predial da SUDAM

Anais do VI Simpósio Brasileiro de Sistemas Elétricos, 2015

Research paper thumbnail of Allocation and Sizing of Dispersed Photovoltaic Generation in Diesel Isolated Electrical Systems Using an Analytical Approach

Journal of Solar Energy Engineering, 2014

This paper proposes an analytical methodology to allocate and size active power photovoltaic gene... more This paper proposes an analytical methodology to allocate and size active power photovoltaic generation (PVG) units with embedded DC/AC inverter (PVGI) to be integrated as concentrated or dispersed generation in isolated medium voltage electrical grids. The methodology considers multiple objectives: improving the electrical grid voltage profile; reducing active power losses and the diesel generation participation. To validate the proposed methodology, the IEEE 33 and 69 buses networks and an isolated real electrical system were simulated. The results obtained demonstrated that the proposed methodology is effective in providing a solution with improvement in voltage profile, active power losses reduction, diesel generation participation reduction.

Research paper thumbnail of Evolution of the passive harmonic filters optimization problem in industrial power systems

DYNA, 2014

Several authors have treated the optimization of passive filters in electric distribution systems... more Several authors have treated the optimization of passive filters in electric distribution systems. Optimization methods like: sequential quadratic programming (SQP), simulated annealing (SA), differential evolution (DE), artificial neural networks (ANN), particle swarm optimization (PSO), genetic algorithm (GA), etc., have been employed for optimizing certain configurations of passive filters. These optimization methods have been employed to solve several formulations of the problem of the project of filters. These formulations can be classified in: formulations of one or several objectives. The objective of the present work is to show the evolution of the formulation of this problem in the lasts years respect to the objective functions and constraints used. This analysis shows how the formulations employed have been upgraded from single-objective to multi-objective formulations to achieve a better representation of this complex problem.