Atualmente, são utilizados diversos processos para a geração de energia elétrica, como por exemplo: usinas hidrelétricas, termoelétricas, nucleares, eólicas, solares, entre outras. Também, neste atual cenário, podem-se ressaltar as usinas virtuais, pois estas são responsáveis por disponibilizar energia por meio de ações de eficiência energética. Portanto, este artigo apresenta o direcionamento a esta forma de geração de energia, a qual fica disponibilizada, por alguma ação de eficiência energética, para outro uso na sociedade. A usina virtual apresentada neste trabalho é baseada em pesquisas de ações de eficiências no sistema nacional de iluminação pública por meio do uso de lâmpadas com maior índice de eficiência e maior vida útil, o que permite a disponibilidade de energia a outros setores, reduzindo gastos quanto a investimentos e melhorando os níveis de tensões do sistema elétrico. Com isso, pode-se considerar como uma usina geradora de energia.

JORGE DE LIMA TOSTES, THIAGO OLIVEIRA COSTA, JOÃO VITOR DOS REIS ALVES, LAURO CORREA DOS SANTOS JUNIOR, PAULO DE LIMA TOSTES, CAROLINA GOMES, DIORGE DE SOUZA LIMA, WELLINGTON DA SILVA FONSECA, MARIA EMÍLIA DE LIMA TOSTES, UBIRATAN HOLANDA BEZERRA

In the search for strategies to mitigate climate change, the promotion of renewable energy is a major challenge worldwide, particularly for developing countries such as Brazil and Colombia, which aim to diversify their power grids by using unconventional renewable energy sources. One of the main obstacles is the development of innovative projects. Increasing oil palm cultivation in the Amazon region for the food and biodiesel industries is producing a large volume of biomass. The present study outlines a methodology for analysis of renewable energy projects based on identification of environmental, economic, and social sustainability criteria and indicators (C&I) for the oil palm production chain. This methodology was then used to develop a computer simulation model in the RETScreen® International software environment for financial viability and risk analysis.

ROSANA CAVALCANTE DE OLIVEIRA, ROGERIO DIOGNE DE SOUZA E SILVA, MARIA EMÍLIA DE LIMA TOSTES

This paper proposes a new methodology based on the use of Resonance Index (RI) analysis as a posteriori decision-making procedure to check solutions of the optimization algorithm NSGA-II against resonance, when applied to the capacitor banks placement problem in radial distribution systems. Most of existing methodologies approach harmonic resonance in the referred problem through the inclusion of constraints in the optimization procedure with respect to the harmonic distortion indexes THD and IHD. However, monitoring only these two parameters is not sufficient to identify specific problems on capacitor banks due to harmonic resonance. To demonstrate this point, a RI analysis using the resonant chart was performed considering a 34-bus radial system. Also, the proposed a posteriori analysis is compared with the one that includes directly RI as a constraint in the optimization procedure, demonstrating that the proposed approach has a better performance with respect to computational time.

JOSE H.D. ONAKA, UBIRATAN H. BEZERRA, MARIA E.L. TOSTES, ÁTHILA S. LIMA

This paper focuses on supplying electrical power for remote communities of the Brazilian Amazon using regional biomass, specifically palm oil biomass, as a primary energy source. The use of Straight Vegetable Oil (SVO) as fuel, is indicated for isolated communities, where the hydro plants or the installation of transmissions line are impracticable. The use of vegetable oils produced in the communities, is a solution when an adequate infrastructure to extracting the oil is available. Brazil is able to use an enormous diversity of vegetable oils, due to a great variety of plants, and the favorable climatic conditions. Technical, economic, environmental and social aspects are analyzed in order to provide a basis for electrical power supply viability in these communities. A case study is presented focused on a typical Brazilian Amazon community located in the State of Pará in order to demonstrate the applicability of the proposed viability strategy.

ANA ROSA DUARTE, UBIRATAN HOLANDA BEZERRA, MARIA EMÍLIA DE LIMA TOSTES, ANDRÉ MONTENEGRO DUARTE, GERALDO NARCISO DA ROCHA FILHO

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.

CLÁUDIO GONÇALVES, J. PAULO A. VIEIRA, DIONE J. A. VIEIRA, M. EMILIA L. TOSTES, BERNARD C. BERNARDES, UBIRATAN H. BEZERRA

in this letter, a methodology is proposed for automatically (and locally) obtaining the shape factor c for the gaussian basis functions, for each support domain, in order to increase numerical precision and mainly to avoid matrix inversion impossibilities. the concept of calibration function is introduced, which is used for obtaining c. the methodology developed was applied for a 2-d numerical experiment, which results are compared to analytical solution. this comparison revels that the results associated to the developed methodology are very close to the analytical solution for the entire bandwidth of the excitation pulse. the proposed methodology is called in this work local shape factor calibration method (lsfcm).

PÉRICLES L. MACHADO, RODRIGO M.S. DE OLIVEIRA, WASHINGTON C.B. SOUZA, RAMON C.F. ARAÚJO, MARIA E.L. TOSTES, CLÁUDIO GONÇALVES

Computer Numerical Control (CNC) is a technology made up of several blocks. Among these, lies the Trajectory Planning block, responsible for reference profile generation that are fed to position control loops. The need for Trajectory Planning arises from the mechanical constraints inherent to every plant to which CNC technology is applied. The machine’s operational limits myst be respected, in order to avoid several issues, such as: loss of precision, early wear of machine’s parts and excessive vibration. This paper proposes a novel smooth real-time trajectory generation setup based on an embedded system platform. A real-time snap and jerk bounded control algorithm is proposed, to achieve continuous and smooth feed motion in traditional Numeric Control code file, dealing both with straight lines and arcs. A local motion blending algorithm, applicable to the proposed method, is also presented. The developed algorithm was deployed to a BeagleBone Black, an embedded System-on-Chip, single board computer and tested in a prototype router machine. A comparison between the proposed method against the seven segments and trapezoidal acceleration methods is presented, both in terms of performance and of real-time computing viability. Simulation and Experimental results demonstrate the effectiveness of the proposed method to generate velocity, acceleration, jerk and snap bounded three dimensional trajectories, reducing the RMS error in up to 8.2% and 22.38% when compared to the Seven Segments and to Trapezoidal Acceleration methods, respectively. Assessing the error area on straight angles, the proposed method produced error areas 24% and 80% smaller when compared to the Seven Segments and to Trapezoidal Acceleration methods, respectively.

PAULO AUGUSTO SHERRING DA ROCHA, WERBESTON DOUGLAS DE OLIVEIRA, MARIA EMÍLIA DE LIMA TOSTES

In this paper, a methodology was developed to analyze the results of energy efficiency programs used in the electricity distribution sector in Brazil. Analyzing the gains obtained through the investments made, and classifying which actions resulted in the best performance, contributed to decision making on the best allocation of investments to obtain the greatest energy savings. The Brazilian Energy Efficiency program was analyzed with a developed non-parametric model, using the data envelopment analysis method, and the categories of projects with better performance were determined. A database of the results from 1704 projects, from 2008 to 2016 in the Energy Efficiency program in Brazil´s electricity distribution sector, was used. The results obtained show that the best performance was achieved by projects in the industrial and cogeneration categories; however, in Brazil these constitute only 4.24% of the projects presented and 5.28% of the total investments in the last eight years, indicating a need to review the regulatory strategies for energy efficiency in this country.

ROGERIO DIOGNE DE SOUZA E SILVA, ROSANA CAVALCANTE DE OLIVEIRA, MARIA EMÍLIA DE LIMA TOSTES

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.

JONATHAN MUÑOZ TABORA, MARIA EMÍLIA DE LIMA TOSTES, EDSON ORTIZ DE MATOS, UBIRATAN HOLANDA BEZERRA, THIAGO MOTA SOARES, BRUNO SANTANA DE ALBUQUERQUE

Este artigo apresenta uma proposta de análise da qualidade de energia elétrica através do indicador THD (total de distorção harmônica) e do Fator de Potência em sistema trifásico de baixa tensão utilizando um sistema de inferência Fuzzy, tendo como resultado uma nova proposta para avaliação da qualidade de energia.

BENEVALDO PEREIRA GONÇALVES, JORGE ALMEIDA BRITO JUNIOR, JANDECY CABRAL LEITE, CARLOS TAVARES DA COSTA JUNIOR, MARIA EMÍLIA DE LIMA TOSTES