Uso de técnicas de otimização baseadas em derivadas como suporte do planejamento operacional de redes de distribuição de energia elétrica

The usual programs for load flow calculation were in general developped aiming the simulation of electric energy transmission, subtransmission and distribution systems. However, the mathematical methods and algorithms used by the formulations were based, in majority, just on the characteristics of the transmittion systems, which were the main concern focus of engineers and researchers. Though, the physical characteristics of these systems are quite different from the distribution ones. In the transmission systems, the voltage levels are high and the lines are generally very long. These aspects contribute the capacitive and inductive effects that appear in the system to have a considerable influence in the values of the interest quantities, reason why they should be taken into consideration. Still in the transmission systems, the loads have a macro nature, as for example, cities, neiborhoods, or big industries. These loads are, generally, practically balanced, what reduces the necessity of utilization of three-phase methodology for the load flow calculation. Distribution systems, on the other hand, present different characteristics: the voltage levels are small in comparison to the transmission ones. This almost annul the capacitive effects of the lines. The loads are, in this case, transformers, in whose secondaries are connected small consumers, in a sort of times, mono-phase ones, so that the probability of finding an unbalanced circuit is high. This way, the utilization of three-phase methodologies assumes an important dimension. Besides, equipments like voltage regulators, that use simultaneously the concepts of phase and line voltage in their functioning, need a three-phase methodology, in order to allow the simulation of their real behavior. For the exposed reasons, initially was developped, in the scope of this work, a method for three-phase load flow calculation in order to simulate the steady-state behaviour of distribution systems. Aiming to achieve this goal, the Power Summation Algorithm was used, as a base for developping the three phase method. This algorithm was already widely tested and approved by researchers and engineers in the simulation of radial electric energy distribution systems, mainly for single-phase representation. By our formulation, lines are modeled in three-phase circuits, considering the magnetic coupling between the phases; but the earth effect is considered through the Carson reduction. Its important to point out that, in spite of the loads being normally connected to the transformers secondaries, was considered the hypothesis of existence of star or delta loads connected to the primary circuit. To perform the simulation of voltage regulators, a new model was utilized, allowing the simulation of various types of configurations, according to their real functioning. Finally, was considered the possibility of representation of switches with current measuring in various points of the feeder. The loads are adjusted during the iteractive process, in order to match the current in each switch, converging to the measured value specified by the input data. In a second stage of the work, sensibility parameters were derived taking as base the described load flow, with the objective of suporting further optimization processes. This parameters are found by calculating of the partial derivatives of a variable in respect to another, in general, voltages, losses and reactive powers. After describing the calculation of the sensibility parameters, the Gradient Method was presented, using these parameters to optimize an objective function, that will be defined for each type of study. The first one refers to the reduction of technical losses in a medium voltage feeder, through the installation of capacitor banks; the second one refers to the problem of correction of voltage profile, through the instalation of capacitor banks or voltage regulators. In case of the losses reduction will be considered, as objective function, the sum of the losses in all the parts of the system. To the correction of the voltage profile, the objective function will be the sum of the square voltage deviations in each node, in respect to the rated voltage. In the end of the work, results of application of the described methods in some feeders are presented, aiming to give insight about their performance and acuity

Male Homosexuality in Brazilian Indexing Languages: Some Ethical Questions

Studies on ethics in information organization have deeply contributed to the recognition of the social dimension of Information Science. The subject approach to information is linked to an ethical dimension because one of its major concerns is related to its reliability and usefulness in a specific discursive community or knowledge domain. In this direction, we propose, through an exploratory research design with qualitative and inductive characteristics, to identify the specific terminology that Brazilian indexing languages allow for terms relating to male homosexuality. We also analyzed the terms assigned to papers published in the Journal of Homosexuality, Sexualities and Journal of Gay & Lesbian Mental Health between the years 2005 to 2009. From this analysis of terms and the Brazilian indexing languages, we see (1) the Brazilian context, (2) imprecision in the terminology, (3) indications of prejudices disseminated by political correctness, (4) biased representation of the subject matter, (5) and the presence of figures of speech.

Does spatial visualization ability improve after studying technical drawing?

Two studies were carried out to analyze whether learning technical drawing improves a person's ability for spatial visualization. Visualization and inductive reasoning tests were applied at the beginning and end of a course in technical drawing in samples of first year engineering students. In both studies it was observed that a moderate percentage of students improved their Visualization test execution. The improvement was similar in men and women. There was no improvement on the inductive reasoning test. The results support the conclusion that the spatial visualization ability can be improved with training.

Design of a labVIEW system applied to predictive maintenance

The implementation of vibration analysis techniques based on virtual instrumentation has spread increasingly in the academic and industrial branch, since the use of any software for this type of analysis brings good results at low cost. Among the existing software for programming and creation of virtual instruments, the LabVIEW was chosen for this project. This software has good interface with the method of graphical programming. In this project, it was developed a system of rotating machine condition monitoring. This monitoring system is applied in a test stand, simulating large scale applications, such as in hydroelectric, nuclear and oil exploration companies. It was initially used a test stand, where an instrumentation for data acquisition was inserted, composed of accelerometers and inductive proximity sensors. The data collection system was structured on the basis of an NI 6008 A/D converter of National Instruments. An electronic circuit command was developed through the A/D converter for a remote firing of the test stand. The equipment monitoring is performed through the data collected from the sensors. The vibration signals collected by accelerometers are processed in the time domain and frequency. Also, proximity probes were used for the axis orbit evaluation and an inductive sensor for the rotation and trigger measurement. © (2013) Trans Tech Publications, Switzerland.

Desenvolvimento e implementação de um sistema de controle de posição e velocidade de uma esteira transportadora usando inversor de frequência e microcontrolador

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Projeto de controladores robustos para sistemas sujeitos a falhas estruturais usando realimentação estática de saída

Pós-graduação em Engenharia Elétrica - FEIS

Pelvimetria radiográfica em diferentes raças de fêmeas caninas adultas (Canis familiaris-LINNAEUS, 1758)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relações obrigacionais entre a ética, o direito e o meio ambiente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A eficiência e a eficácia das normas antidumping na OMC e suas repercussões no direito concorrencial brasileiro

Pós-graduação em Direito - FCHS

Estudo de deslocamentos na tomada d'água da UHE Jaguari devidos à reação álcali-agregado

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Renovação Carismática Católica, através do Seminário de Vida no Espírito Santo-Adamantina - (1997-2003)

Pós-graduação em História - FCLAS

Vitrina, design e emoção: uma investigação sobre a percepção visual feminina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de viabilidade técnica-econômica para a aplicação de inversores de frequência em sistemas de bombeamento de baixa potência

Pós-graduação em Engenharia Mecânica - FEG

Os verbos ver, ouvir e sentir e a expressão da evidencialidade em língua portuguesa

Pós-graduação em Estudos Linguísticos - IBILCE

Aspectos éticos em representação do conhecimento em temáticas relativas à homossexualidade masculina: uma análise da precisão em linguagens de indexação brasileiras

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)