Mixed-integer convex model for VAr expansion planning

This paper presents a mixed-integer convex-optimization-based approach for optimum investment reactive power sources in transmission systems. Unlike some convex-optimization techniques for the reactive power planning solution, in the proposed approach the taps settings of under-load tap-changing of transformers are modeled as a mixed-integer linear set equations. Are also considered the continuous and discrete variables for the existing and new capacitive and reactive power sources. The problem is solved for three significant demand scenarios (low demand, average demand and peak demand). Numerical results are presented for the CIGRE-32 electric power system.

A simulation tool for transient stability analysis on vector computers

This paper deals with transient stability analysis based on time domain simulation on vector processing. This approach requires the solution of a set of differential equations in conjunction of another set of algebraic equations. The solution of the algebraic equations has presented a scalar as sequential set of tasks, and the solution of these equations, on vector computers, has required much more investigations to speedup the simulations. Therefore, the main objective of this paper has been to present methods to solve the algebraic equations using vector processing. The results, using a GRAY computer, have shown that on-line transient stability assessment is feasible.

A new family of zero-current-switching PWM converters and a novel HPF-ZCS-PWM boost rectifier

A new family of direct current (DC) to DC converters based on a zero current switching pulse width modulated (ZCS-PWM) soft commutation cell is presented. This ZCS-PWM cell is consists of two transistors, two diodes, two inductors and one capacitor; and provides zero voltage turn-on to the diodes, a zero-current turn-on and a zero-current zero-voltage turn-off to the transistors. In addition, a new commutation cell in a new ZCS-PWM boost rectifier is developed, obtaining a structure with power factor near the unity, high efficiency at wide load range and low total harmonic distortion in the input current.

Estudo sobre o panorama da energia elétrica no Brasil e tendências futuras

Pós-graduação em Engenharia Elétrica - FEB

Construção e avaliação térmica de um sistema concentrador parabólico com seguidor solar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inclusão das representações de gary e de skilling-umoto em modelos de linhas de transmissão trifásicas: Aplicação em simulações de transitórios eletromagnéticos em sistemas de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Análise de desempenho de redes de comunicação wireless em aplicações de Smart Grid

Pós-graduação em Engenharia Elétrica - FEIS

Meta-heurísticas para o problema de planejamento de expansão da rede de transmissão de energia elétrica considerando restrições de segurança

Pós-graduação em Engenharia Elétrica - FEIS

Retificador entrelaçado com elevado fator de potência para operação de um veículo trólebus alimentado por redes em CA Ou CC

This paper presents the development and the main results for an interleaved boost rectifier operating as a special input power stage for a trolleybus type vehicle, allowing its feeding by alternate current (AC) or direct current (DC) distribution power systems. When feeding with two wires (single phase) alternate current distribution system, the converter accomplish active power factor correction, providing a relatively sinusoidal current with low total harmonic distortion (THD) and fully complying with IEC 61000-3-4 standards. In addition, a management control system promotes the required automatic operation changes for the proposed rectifier when the vehicle is changing from the DC distribution power system to the AC distribution power system and vice-versa, keeping its original electrical DC system characteristics for the adjustable speed driver sub-system. The main experimental results for a prototype rated at 150kW are presented, considering its application for a trolleybus with DC adjustable speed driver, demonstrating the proposed converter benefits and the possibility of AC feeding system for trolleybus type vehicle.

Viabilidade econômica da implantação de compensadores série dinâmicos em redes de distribuição de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Os financiamentos do BNDES às usinas sucroalcooleiras paulistas: potencialidades da ampliação da desigualdade regional no Brasil

The present work focuses on addressing the financing made by BNDES to sucroalcooleiras plants located in the State of São Paulo in Brazil. The study points out the Bank loans at São Paulo due to accumulation of plants technical objects that BNDES loans provide the State, with the installation of new equipment, machinery and services in canavieiros enterprises for electric power generation. Sucroalcooleiras plants are getting financing from BNDES to expand and diversify power generation in the country, mainly in São Paulo, because residential and industrial consumption of electricity grows annually. The offer of new financing to sucroalcooleiras plants for energy production Sao Paulo electric provides continued technical density in São Paulo and the expansion of regional inequality in the country. Therefore, the present study highlights for the period 2008 to 2013 the BNDES financing for are sucroalcooleiras plants in order to highlight the consolidation of technical objects in the State and show that the funding will help in the expansion of regional disparity

Feasibility of solar heating systems composed of recyclable packaging for low-income rural communities

Solar heaters are an appropriate technology in tropical and sub-tropical climates to heat bath water by solar energy. Low-cost solar heaters meet the demand of low-income rural communities which currently do not have access to this technology. Current research analyzes the economic viability of solar heaters, built with recyclable materials, to reduce electric energy bill. A solar heating system was built consisting of recyclable materials in accordance with the manuals provided by the Secretariat of Environment of the state of Paraná (SEMA). Duration of use of electric showers by families of rural properties was determined to calculate expenses and billing of electricity. Simulation and material costs showed that the system was feasible. Commercial solar heaters could be replaced at a cost of R$ 22.61 per month during 13 months.

Estimação espaço-temporal das perdas não técnicas no sistema de distribuição de energia elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Células-combustível a etanol direto embarcadas em aeronaves: estudo de utilização e recuperação de calor residual

Pós-graduação em Engenharia Mecânica - FEG

Análise termoeconômica e eficiência ecológica de uma termoelétrica com absorção química de CO2

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)