Developing an optimization tool for evaluating the transmission system expansion

The transmission system is responsible for connecting the power generators to consumers safely and reliably, its constant expansion is necessary to transport increasing amounts of electricity. In order to help the power systems engineers, an optimization tool for optimize the expansion of the transmission system was developed using the modeling method of the linearized load flow and genetic. This tool was designed to simulate the impact of different scenarios on the cost of transmission expansion. The proposed tool was used to simulate the effects of the presence of distributed generation in the expansion of a fictitious transmission system, where it was found a clear downward trend in investment required for the expansion of the transmission system taking account of increasing levels of distributed generation.

On energy harvesting form time-limited excitations: simulations and case study

Linear resonant harvesters have been the most common type of generators used to scavenge energy from mechanical vibrations. When subject to harmonic excitation, good performance is achieved once the device is tuned so that its natural frequency coincides with the excitation frequency. In such a situation, the average power harvested in a cycle is proportional to the cube of the excitation frequency and inversely proportional to the suspension damping, which is sought to be very low. However, a very low damping involves a relatively long transient in the system response, where the classical formulation adopted for steady-state regimes do not hold. This paper presents an investigation into the design of a linear resonant harvester to scavenge energy from time-limited harmonic excitations involving a transient response, which could be more likely in some practical situations. An application is presented considering train-induced vibrations.

Higher spin constraints and the super (W∞/2 ⊕ W1+∞/2) algebra in the super eigenvalue model

We show that the partition function of the super eigenvalue model satisfies, for finite N (non-perturbatively), an infinite set of constraints with even spins s = 4, 6, . . . , ∞. These constraints are associated with half of the bosonic generators of the super (W∞/2 ⊕ W1+∞/2) algebra. The simplest constraint (s = 4) is shown to be reducible to the super Virasoro constraints, previously used to construct the model.

Classical and quantum N = 1 super W∞-algebras

We construct higher-spin N = 1 superalgebras as extensions of the super-Virasoro algebra containing generators for all spins s ≥ 3/2. We find two distinct classical (Poisson) algebras on the phase superspace. Our results indicate that only one of them can be consistently quantized.

Simetrias e sólitons do modelo de toda conforme afim

Pós-graduação em Física - IFT

A gestão de resíduos da construção civil: iniciativas na bacia hidrográfica Tietê-Jacaré e uma proposta para o município de Bauru (SP)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de um sistema de proteção e metodologia para localização de faltas em sistemas de distribuição

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uma abordagem geométrica para princípios de localização de integrais funcionais

Pós-graduação em Física - IFT

Quebra de Simetria no Universo Primordial

Pós-graduação em Física - IFT

Gerenciamento de resíduos da construção civil: análise e atualização dos estudos realizados na UNESP-FEG para o município de Guaratinguetá

The construction industry is a large consumer of natural resources and one of the largest generators of residues with significant impacts on the environment. Because of the large production of Construction Industry Residues (RCC), it is essential reliable and updated information about generation, composition and classification sources of these residues, especially for management, recycling and final disposal. RCC represent the most part of solid residues generated in a city. In this way, the management of these residues is an issue that is gaining increasing importance in the Brazilian scenario, since the legal and society requirements to internalize the sustainability in the construction process - since the extraction, use, wastage savings, reutilization until the appropriate discard has been increasing in the last years. The present work objective is updating the quantities produced and collected in Guaratinguetá-SP, based on data collected with the municipal administrative entities that act direct or indirectly in the RCC management, elaborate a detailed bibliographic review, with special attention to the graduate works that were realized in FEG about this theme. With this material, scenarios to a better adequacy of the administrative structure to managements RCC activities, as well as was suggested actions to achieve these scenarios

Estudo de viabilidade técnica e econômica da utilização de geração diesel no horário de ponta

Given the current energy crisis experienced in our country with the lack of rain in some areas, the energy distributors were forced to resort to thermal power plants to complement their energy production; raising the cost of electricity generation, they have been forced to repass this value to the customers through the Tariff Flags. Concerned about a substantial increase in their electric bill, some consumers were forced to look for alternatives so that their results are not affected. The use of diesel generation at peak hours is a relatively simple and inexpensive alternative that has been widely used for several industrial, commercial and service customers. In this present work, we conducted a feasibility study of the use of diesel generators at peak hours in a medium-sized hospital, calculating the depreciation period for the investment through savings in electricity bills

Gerenciamento de resíduos da construção civil: análise e atualização dos estudos realizados na UNESP-FEG para o município de Guaratinguetá

The construction industry is a large consumer of natural resources and one of the largest generators of residues with significant impacts on the environment. Because of the large production of Construction Industry Residues (RCC), it is essential reliable and updated information about generation, composition and classification sources of these residues, especially for management, recycling and final disposal. RCC represent the most part of solid residues generated in a city. In this way, the management of these residues is an issue that is gaining increasing importance in the Brazilian scenario, since the legal and society requirements to internalize the sustainability in the construction process - since the extraction, use, wastage savings, reutilization until the appropriate discard has been increasing in the last years. The present work objective is updating the quantities produced and collected in Guaratinguetá-SP, based on data collected with the municipal administrative entities that act direct or indirectly in the RCC management, elaborate a detailed bibliographic review, with special attention to the graduate works that were realized in FEG about this theme. With this material, scenarios to a better adequacy of the administrative structure to managements RCC activities, as well as was suggested actions to achieve these scenarios

Estudo de viabilidade técnica e econômica da utilização de geração diesel no horário de ponta

Given the current energy crisis experienced in our country with the lack of rain in some areas, the energy distributors were forced to resort to thermal power plants to complement their energy production; raising the cost of electricity generation, they have been forced to repass this value to the customers through the Tariff Flags. Concerned about a substantial increase in their electric bill, some consumers were forced to look for alternatives so that their results are not affected. The use of diesel generation at peak hours is a relatively simple and inexpensive alternative that has been widely used for several industrial, commercial and service customers. In this present work, we conducted a feasibility study of the use of diesel generators at peak hours in a medium-sized hospital, calculating the depreciation period for the investment through savings in electricity bills

Making the case for grid-connected photovoltaics in Brazil

In the developed world, grid-connected photovoltaics (PVs) are the fastest-growing segment of the energy market. From 1999 to 2009, this industry had a 42% compound annual growth-rate. From 2009 to 2013, it is expected to grow to 45%, and in 2013 the achievement of grid parity - when the cost of solar electricity becomes competitive with conventional retail (including taxes and charges) grid-supplied electricity - is expected in many places worldwide. Grid-connected PV is usually perceived as an energy technology for developed countries, whereas isolated, stand-alone PV is considered as more suited for applications in developing nations, where so many individuals still lack access to electricity. This rationale is based on the still high costs of PV when compared with conventional electricity. We make the case for grid-connected PV generation in Brazil, showing that with the declining costs of PV and the rising prices of conventional electricity, urban populations in Brazil will also enjoy grid parity in the present decade. We argue that governments in developing nations should act promptly and establish the mandates and necessary conditions for their energy industry to accumulate experience in grid-connected PV, and make the most of this benign technology in the near future. (C) 2010 Elsevier Ltd. All rights reserved.

A Model-Based Approach for Small-Signal Stability Assessment of Unbalanced Power Systems

In this paper, a modeling technique for small-signal stability assessment of unbalanced power systems is presented. Since power distribution systems are inherently unbalanced, due to its lines and loads characteristics, and the penetration of distributed generation into these systems is increasing nowadays, such a tool is needed in order to ensure a secure and reliable operation of these systems. The main contribution of this paper is the development of a phasor-based model for the study of dynamic phenomena in unbalanced power systems. Using an assumption on the net torque of the generator, it is possible to precisely define an equilibrium point for the phasor model of the system, thus enabling its linearization around this point, and, consequently, its eigenvalue/eigenvector analysis for small-signal stability assessment. The modeling technique presented here was compared to the dynamic behavior observed in ATP simulations and the results show that, for the generator and controller models used, the proposed modeling approach is adequate and yields reliable and precise results.