Orientador: Luis Carlos Origa de Oliveira / Banca: José Carlos Rossi / Banca: Olivio Carlos Nascimento Souto / Resumo: O presente trabalho avalia a viabilidade técnica da aplicação de compensação reativa em circuitos secundários aéreos de baixa tensão, através da aplicação de capacitores e / ou filtros para aplicação em Baixa Tensão, buscando assim uma otimização dos reativos presentes nas redes secundárias. Considerando-se as constantes mudanças que vêm ocorrendo no cenário de distribuição de energia elétrica, devido ao grande avanço da eletrônica de potência e de cargas não lineares cada vez mais presentes no sistema elétrico, fazem-se necessários estudos para diagnosticar como e em que níveis tais mudanças podem estar afetando as características das redes de distribuição. Verifica-se que tais cargas, possuem um baixo fator de potência, e podem aumentar significativamente o nível de correntes harmônicas devido às técnicas de chaveamento utilizadas nestes dispositivos. Com isto, acentuam-se os problemas da propagação das distorções de forma de onda das correntes às tensões da rede, além de aumentar consideravelmente as perdas de energia elétrica ao longo de seus condutores e transformadores. Há necessidade de se conhecer as características dessas cargas de forma a permitir a correta modelagem das mesmas. O objetivo deste trabalho é identificar o perfil da rede secundária frente aos níveis de harmônicos e fator de potência, permitindo a adequada aplicação de filtros e capacitores para instalação no secundário dos transformadores de distribuição, visando a correção do fator de potência nos circuitos, redução do reativo circulante, das perdas elétricas e eventualmente dos níveis de distorção harmônica. Avaliando-se as interferências no carregamento dos transformadores de distribuição e melhoria do perfil da tensão de alimentação. Neste sentido, foi feita uma campanha de monitoramento em alguns circuitos selecionados... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This paper seeks to evaluate the technical feasibility of applying for compensation reactive side air circuits in low-voltage, by the application of capacitors and / or filters for use in the Low Voltage, thereby seeking an optimization of reactive present in the secondary networks. Analysis with a focus on secondary distribution network should consider a new factor, which is the proliferation of non-linear loads. Considering the constant changes that are occurring in the scenario of distribution of electric energy, due to the general advancement of power electronics and nonlinear loads increasingly present in the electrical system, are made necessary studies to diagnose how and to what levels such changes may be affecting the characteristics of distribution networks. It appears that such loads, have a low power factor, and can significantly increase the level of harmonic currents because of the techniques used in these switching devices. With this, stressing the problems of the spread of distortions of waveform of the current tensions to the network, in addition to considerably increase the loss of power over their drivers and processors. Thus, the objective of this study is to identify the profile of the network front secondary levels of harmonics and power factor, allowing the proper implementation of filters and capacitors for installation of transformers in the secondary distribution, aiming to correct the power factor in circuits, Reducing the reactive stock, loss of electrical and possibly the levels of harmonic distortion. Judging is interference in the shipment of processors for distribution and improving the profile of the supply voltage. In this sense, there was a campaign tracking in some selected circuits, computer simulations were also conducted, equipment developed and deployed pilot projects. / Mestre

State-of-the art electronic systems include ever more features and gather mixed-signal subsystems, possibly from different physical domains. At the same time, cost and development time are reduced; stressing the need for an efficient design flow for fast and reliable design. The present thesis contributes to the construction of an improved design flow supported by mixed-signal hardware description languages (HDL-AMS). In a hierarchical view, the electronic systems are recursively divided into subsystems, down to basic cells and transistor level. The typical design flow results of a top-down synthesis, from the system specifications to the physical realizations, and of a bottom-up validation, from the test of the basic cells up to the test of the system. To improve the link between the technological level and the basic cells, we develop a measurement-based analog ID card which aims to optimize the analog performance and the reliability at high temperature by enabling the choice of optimal process (bulk vs. partially-depleted silicon-on-insulator (SOI) vs. fully-depleted SOI), optimal devices (e.g. multi-threshold voltages process) and optimal bias (weak vs. moderate vs. strong inversion). In the present thesis, we deal with the following analog performance parameters: gain, gain-bandwidth product, MOSFET mismatch in weak inversion and harmonic distortion of MOSFETs in triode regime. We show that SOI transistors are still advantageous over bulk in deep-submicron CMOS technologies and that short-channel SOI transistors can safely be used for mixed-signal operation up to 250°C. The analog ID card can be included in the design flow supported by HDL-AMS. Behavioral models for the basic cells are developed using such languages and further assembled into a ÄÓ modulator with continuous-time integrators as it is a good candidate for low-power consumption and operation at high temperature. The related design issues are assessed using the behavioral models and a design optimization method is presented for a key building block, an active RC integrator with passive resistors.

The presence of information and communication technologies in the field of energy is increasing every day. Smart grid subject which aims to increase the percentage of energy generation through renewable resources and to make consumers to be involved in grid actively, is gaining importance day by day. In order to provide an effcient and reliable operation of smart grid network, it is necessary to collect relevant parameters from network components via communication infrastructure and to evaluate collected information. Also, with the inclusion of distributed energy sources in the power lines, collection of relevant data becomes important in order to ensure the quality of power. In the scope of this study, to measure current parameters, two DSP based electronic circuits and necessary embedded software have been developed. Data acquisition card is a fixed device which is to be installed to a point on the power line to gather current value samples. By means of being fed through magnetic induction from the line, this part of the system could stay on-line permanently and this allows taking measurements on demand. Sampling of line current is performed through principle of magnetic induction from the line on current sensing instrument which is connected to data-acquisition part. Also by utilization of clamp-on instruments, cutting of energy lines is not needed. Samples received by control card over radio frequency or infrared communication, are evaluated with the help of Discrete Fourier Transform (DFT). Control card can show information about Root mean square (RMS) value and harmonic components of line current and total harmonics distortion (THD) on graphic LCD. Present state of the system was tested in LV and MV environments and shown to be used on distribution lines. The system presented in this study is open to improvements and suggestions to make the system to be able to work on high voltage lines are made.

Abstract The objective of this thesis is to perform the AC/DC load flow and harmonic analysis for the power supply system of mass rapid transit (MRT) system. According to the computer simulation of stochastic harmonic load flow analysis, the mean value and standard deviation of voltage harmonic distortion are derived. The mitigation of harmonic distortion has been proposed by the proper design of harmonic filter. The mathematical model of 12 pulse uncontrolled rectifiers without interphase transformers is derived and applied in the AC/DC load flow analysis. The system voltage profiles and power consumption are obtained by computer simulation with the models derived. The Taipei MRT system is selected for simulation to solve the peak and off peak load of target year, bus voltage and power demand, and the harmonic current injection of traction substation. The voltage harmonic distortion is then calculated for each time snapshot according to the operation modes of all train sets on the main lines. According to the dynamic load behavior of train sets, the stochastic harmonic load flow analysis is executed to find the variation of harmonic distortion. To improve the power quality of MRT power systems, the proposed hybrid filter, which consists of both passive filter and active filter, is considered in the simulation. It is found that better distortion mitigation can be obtained with the hybrid filter by taking into account the stochastic harmonic current injection at the traction substations.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T14:42:53Z No. of bitstreams: 2 Dissertação - André Luiz Carneiro Franco - 2015.pdf: 2564368 bytes, checksum: 93761b2c7af9677536a7897fd4aa57f3 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T14:44:04Z (GMT) No. of bitstreams: 2 Dissertação - André Luiz Carneiro Franco - 2015.pdf: 2564368 bytes, checksum: 93761b2c7af9677536a7897fd4aa57f3 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-07T14:44:04Z (GMT). No. of bitstreams: 2 Dissertação - André Luiz Carneiro Franco - 2015.pdf: 2564368 bytes, checksum: 93761b2c7af9677536a7897fd4aa57f3 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-09-15 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This work presents an analysis and optimization metho dology for the AC machines stator windings design, based on magnetomotive force harmonic distortion study. For that, the three-phase double layer integral and fractional-slot windings are chosen. At first, magnetomotive force in conventional windings study is p erformed, comparing harmonic analysis by distortion and Fourier sp ectrum with the traditional calculation metho dology of winding factors. In relation to the metho d, the stator windings arrangement optimization using genetic algorithms is prop osed, in order to suggest alternative optimized layouts. The results are presented and discussed. / Este trabalho apresenta metodologia para análise e otimização de geometrias de enrolamentos de estator de máquinas CA, baseada no estudo da distorção harmônica associada à curva de força magnetomotriz no entreferro. Para tal, opta-se p elo estudo dos enrolamentos trifásicos de dupla camada integrais e fracionários. Primeiramente é realizado o estudo da força magnetomotriz dos enrolamentos convencionais, confrontando a análise harmônica através da distorção e espectro de Fourier com a metodologia tradicional de cálculo dos fatores de enrolamento. Definido o método, propõe-se a otimização do arranjo de enrolamentos de estator utilizando algoritmos genéticos, com o objetivo de sugerir geometrias alternativas otimizadas. Os resultados obtidos são apresentados e discutidos.

This paper presents the design and development of a novel Arc Welding Power Supply utilizing a modified two-switch forward converter topology. The proposed design improves the power quality by improving power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. Hardware implementation of the proposed design was built on a scaled-down prototype for a proof-of-concept of the new topology. The prototype specifications were created for a 5A, 20V output with a 20-24V, 60Hz input. This project demonstrated that the proposed new topology was successful in obtaining a near unity power factor and a total harmonic distortion of less than 2%. Additionally, the prototype followed the simulation and calculations of a boost-buck function while varying duty cycle, and the final measurements aligned well with waveforms from the simulation.

This Diploma thesis deals with design of for power factor correction device for mid-frequency-range induction heating and also with assessment of correction device influence in harmonically distorted environment from the distribution net point of view. Research chapters contain of main characteristics of electrical power quality and theoretical background of reactive power, which is in our case caused by driven non-linear elements. Further, the heating power supply block is explained and simulations of power consumption in Matlab - Simulink is done, within the prove of corrective tools design. After the build of corrective tool assemblies, measurements are matched with the simulation results.

Proliferation of non-linear, single-phase power electronics loads, such as personal computers, television sets, CFLs, has resulted in thousands of individual small harmonic current injectors connected to a distribution feeder network. Harmonic standard: IEC 1000-3-2 classifies such loads as Class D, “low-voltage” equipment with current emissions limited to 16A/Phase. Individual harmonic contributions of such loads appear insignificant; their collective contribution, however, is a matter of concern. The average order of voltage distortion usually varies between 4-6%; current distortion, however, is usually of the order of 100%. Limitations and high-costs associated with conventional harmonic mitigation measures, has furthered the need for regulation and alternative strategies. The objective of this research is to predict, and mitigate the effects of harmonic proliferation in the main supply current measured at the point of common coupling (PCC). An equivalent circuit model – an aggregation of single phase power electronics loads connected to the distribution feeder network is proposed as a part of a forward solution. Each load, individually, behaves as a harmonic current source; the proposed model combines these individual harmonic current injectors into a single harmonic source connected at the PCC and their collective contribution as a single composite harmonic signal. It represents harmonic conditions at the PCC and provides a theoretical measure of harmonic distortion in the supply current. Such a model finds application during harmonic compliance testing for single-phase power electronics loads; it simulates and predicts the harmonic response of such loads using a theoretical pure 60 Hz sine wave as the supply voltage diffcult to obtain physically, yet critical to such tests. The accuracy of the equivalent circuit model in predicting a harmonic response is pivotal to a successful forward solution. A feed-backwards mechanism is proposed. For a given harmonic supply voltage and circuit configuration of the equivalent circuit model, the feed-backwards method generates the modeled response and compares it to a reference physical response. Finally, it optimizes the circuit configuration to a unique Correction Factor that facilitates an accurate modeled response. Three optimization algorithms, labeled as Response Optimization algorithms have been developed to execute the feed-backwards mechanism. These algorithms are written in FORTRAN-90. / text

This study addresses quality control for Light Emitting Diodes (LED) according to fouraspects, the power factor of LED lamps, their harmonics and total harmonic distortion (THD), the luminosity for total power to radiated power ratio. It focuses on four brands and six different LED lamps, and concludes that IKEA's LED lamps pertain as the quality lamp, with a power factor over 0.9, THD less than 4% and a power to radiated light of over 4%.

Esta pesquisa apresenta um estudo investigativo da análise modal aplicada a Sistemas de Distribuição (SDs) frente às distorções harmônicas, no contexto da Qualidade da Energia Elétrica (QEE). A partir do método de análise da ressonância modal, foi conduzido um estudo investigativo para apontar quais barramentos são mais sensíveis e permitem uma melhor observação frente às distorções harmônicas. Vale adiantar que o método de análise de ressonância modal, o qual é fundamentado na decomposição espectral da matriz de admitância do sistema elétrico, já apresenta interessantes trabalhos voltados para sistemas de transmissão. O desafio desta pesquisa foi então investigar a sua aplicação para SDs com um direcionamento às distorções harmônicas, bem como ao seu monitoramento. Dentre os resultados encontrados no desenvolvimento da pesquisa, destaca-se um melhor entendimento do problema das distorções harmônicas, o qual permitiu evidenciar a sensibilidade e a observabilidade dos SDs testes frente ao problema definido no contexto da QEE. / This research presents an investigative study of the modal analysis applied to Distribution Systems (DSs) in the context of Power Quality (PQ) considering the harmonic distortions. From the modal resonance analysis, an investigative study was conducted to indicate which bus bars are more sensitive and allow better observation in face of harmonic distortions. It is worth mentioning that the method of modal resonance analysis, which is based on the spectral decomposition of the admittance matrix of the electric system, already presents interesting applications focused on transmission systems. The challenge of this research was to investigate its application to DSs focusing on harmonic distortions, as well as their monitoring. Among the observed results of the research development, a better understanding of the harmonic distortions problem was achieved, which made it possible to highlight the sensitivity and observability of the DSs tests against the problem defined in the context of the PQ.