Analise e controle da energia eletrica atraves de tecnicas de processamento digital de sinais

Orientador: Sigmar Maurer DeckmannTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Este trabalho apresenta uma Metodologia Seletiva de Identificação das parcelas consideradas ideais de tens~ao e corrente eletricas em um sistema polifasico, bem como das parcelas associadas a disturbios e fenomenos responsaveis pela deterioração da qualidade de energia. Tal metodologia e descrita por meio da aplicação de tecnicas de processamento digital de sinais, possibilitando a formulação de filtros digitais, detectores de sequencia positiva, algoritmos de identicação de frequencia, Multiplicadores de Lagrange, etc, as quais podem ser implementados em processadores de aritmetica saturada (ponto-fixo). Atraves de tal metodologia e das tecnicas estudadas, e possivel discutir e propor uma abordagem alternativa na definição de uma Teoria de Potência Unificada, adequada a condições de formas de onda não-senoidais e/ou assimetricas, bem como propor estrategias de compensação para condicionadores de energia, tais como os Filtros Ativos de Potência. O trabalho tambem apresenta um breve estudo sobre os controladores digitais necessarios à implementação pratica de um filtro ativo de potência, destacando a proposta de um controlador repetitivo para compensação seletiva de harmônicos dominantes, o qual foi avaliado através da implementação de um protótipo de filtro ativo em paralelo com a redeAbstract: Considering the areas of Power Quality and Power Conditioning, this work proposes and discusses the use of a Selective Identification Methodology in order to identify the so-called ideal, as well as the disturbing, voltage and current components in a general polyphase power system. Such methodology is presented and described by means of discrete-time signal processing techniques, which allows the implementation of useful digital filters, positive sequence detectors, frequency identification algorithms, Lagrange Multipliers, etc. Special attention is directed to the implementation of such techniques in finite word length or fixed-point DSP and microprocessors. Considering the proposed selective methodology and the related digital algorithms, it is possible to discuss and suggest an alternative approach to define a promising Unified Power Theory, which could be adequate for non-sinusoidal and unbalanced waveform conditions. Moreover, the same methodology can be used to propose several compensation strategies for different power conditioning equipments, such as e.g., Active Power Filters. This work also presents a brief study concerning the required digital controllers for the experimental implementation of a shunt active filter prototype. Particularly, it has been pointed out the repetitive controller applied to the implementation of a selective harmonic current compensator. The selective compensator allows minimizing the dominant harmonic components in order to reduce the THD levels and to increase the power factor of a specific installationDoutoradoEnergia EletricaDoutor em Engenharia Elétric

ARQUITETURA DO MEDIDOR COGNITIVO DE ENERGIA

As Redes Inteligentes de Energia indicam para uma nova arquitetura dos sistemas de distribuição de energia elétrica, a qual deve se consolidar nas próximas décadas, em um cenário repleto de dispositivos e sistemas dotados de algum grau de “inteligência” artificial. Neste cenário, a possibilidade de comunicação bidirecional entre o usuário e a rede de energia elétrica será imprescindível para integração dos vários dispositivos e agentes em uma Rede Inteligente. Atualmente, há muita pesquisa e desenvolvimento sobre os chamados medidores inteligentes de energia e sobre os medidores cognitivos de energia, que possibilitam a integração e comunicação dos dispositivos numa rede de dados e facilita a atuação de uma Rede Inteligente de Energia. Nesse contexto, este trabalho propõe um tutorial sobre as tecnologias, métodos e etapas que podem ser utilizadas no desenvolvimento de medidores cognitivos de energia. Palavras-chave: Inteligência Artificial, Medidores Inteligentes de Energia, Redes Inteligentes de Energia

Flexible active compensation based on load conformity factors applied to non-sinusoidal and asymmetrical voltage conditions

This study proposes a flexible active power filter (APF) controller operating selectively to satisfy a set of desired load performance indices defined at the source side. The definition of such indices, and of the corresponding current references, is based on the orthogonal instantaneous current decomposition and conformity factors provided by the conservative power theory. This flexible approach can be applied to single- or three-phase APFs or other grid-tied converters, as those interfacing distributed generators in smart grids. The current controller is based on a modified hybrid P-type iterative learning controller which has shown good steady-state and dynamic performances. To validate the proposed approach, a three-phase four-wire APF connected to a non-linear and unbalanced load has been considered. Experimental results have been generated under ideal and non-ideal voltage sources, showing the effectiveness of the proposed flexible compensation scheme, even for weak grid scenarios

CONSIDERAÇÕES SOBRE A GESTÃO DE ENERGIA ELÉTRICA EM INSTITUIÇÕES PÚBLICAS – ESTUDO DE CASO COM GERAÇÃO FOTOVOLTAICA

Considerando que os custos com energia elétrica representam parte significativa do custeio das instituições públicas de ensino superior, este trabalho busca mostrar que existem novos modelos de contratação e gestão de energia elétrica que podem contribuir para mitigação deste impacto financeiro nas contas das instituições. Neste sentido, foram discutidas alternativas que consideram apenas a contratação de energia elétrica no mercado livre, passando por simulações que consideram a implantação de usinas fotovoltaicas financiadas por ente privados, com remuneração através de contratos de performance, ou financiadas junto a instituições financeiras. Também foi considerada a alternativa de implantação gradual de geração fotovoltaica a partir da economia gerada pela contratação de energia elétrica de forma mais econômica, ou seja, no mercado livre. Assumindo um cenário de 30 anos, os resultados indicaram que a implantação gradual de geração fotovoltaica tem potencial para uma economia financeira acumulada de 40,5%, quando comparado com a compra de energia elétrica diretamente do mercado cativo (concessionárias).

ECONOMIC, ENVIRONMENTAL AND PRODUCTIVE PRACTICES INFLUENCE ON THE INDUSTRIAL ENERGETIC EFFICIENCY

The industrial energetic efficiency (EE) is recognized as one of the main factors for the reduction of gas emissions that cause the greenhouse effect and for the improvement of the industrial competiveness. Within this context, many papers of the international literature have proposed different indicators of industrial, economic and environmental behavior, so as to promote the EE inside the industries. However, such proposals do not generally check the result of the joint work for more than one indicator in the organizations, making more global analysis more difficult related to EE. This paper aims to check which environmental, economic and industrial practices indicators influence the EE of the industries.  The data have been collected from the framework developed by Trianni et al. (2014), that analysed the main energetic efficiency measures for the technologies: motors, lighting, compressed air and HVAC systems (heating, ventilation and air conditioning). A logistic regression model has been adjusted for understand the relationship the economic, environmental and productive practices behavior on the energetic efficiency. Results suggest that a healthy workplace enables investments in equipment and machinery, allowing the EE inside the industries.

A Selective Harmonic Compensation and Power Control Approach Exploiting Distributed Electronic Converters in Microgrids

Made available in DSpace on 2020-12-12T01:39:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Norges Forskningsråd This paper proposes an approach to obtain harmonic compensation and power control by exploiting the electronic power converters deployed in low-voltage microgrids. By the proposed approach, distributed harmonic current compensation is achieved without interfering with the converter's power exchange involved in interfacing the local energy resources (e.g., renewable sources, storage devices) with the grid. The control framework refers to a master/slave microgrid architecture where distributed power converters play as slave units, coordinated by a centralized controller; the data exchange among agents occurs periodically, concerns current magnitudes only, and can be fulfilled by communication means of limited performance. The paper shows the achievable results in terms of power quality improvements and discusses the challenges related with the aimed objective. The proposed methodology is evaluated by means of simulation and experimental tests on a single-phase low-voltage microgrid prototype comprising nonlinear loads and two converters. Different cases of generation limits, load variations, voltage levels, voltage distortions, and line parameters are considered in the tests reported. In addition, the robustness of the proposed method to non-ideal and faulty communication links is discussed and shown by means of experimental results. Group of Automation and Integrated Systems Sao Paulo State University (UNESP), Av. Três de Março 511, 18087-180 Sorocaba Department of Electric Power Engineering Norwegian University of Science & Technology (NTNU), O.S. Bragstads plass 2 Graduate Program in Electrical Engineering Federal University of Minas Gerais (UFMG), Av. Antônio Carlos 6627 Department of Management and Engineering University of Padova, Stradella San Nicola 3 Group of Automation and Integrated Systems Sao Paulo State University (UNESP), Av. Três de Março 511, 18087-180 Sorocaba FAPESP: 2016/08645-9 FAPESP: 2017/24652-8 FAPESP: 2018/22172-1 Norges Forskningsråd: f261735/H3

Multi-task control strategy for grid-tied inverters based on conservative power theory

In recent years, the concept of decentralizing power generation through the deployment of distributed generators (DGs) has been widely accepted and applied, driven by the growing market of renewable energy sources, in particular photovoltaic, wind and small hydro. These distributed generators are normally equipped with a switching power interface (inverter), acting as front end with the grid. In this scenario this paper proposes a multi-task control strategy for distributed generation inverters that simultaneously allows the DG system to inject the available energy, as well as to work as a voltage drop compensator or as an active power filter, mitigating load current disturbances and improving power quality of the grid. The main contribution of the proposed system, with respect to other solutions in the literature, is that the proposed control loops are based on the Conservative Power Theory decompositions. This choice provides decoupled power and current references for the inverter control, offering a very flexible, selective and powerful control strategy for the DG system. The paper also discusses the choice of the current waveform for injecting/absorbing active power into/from the grid, and both sinusoidal and resistive references have been compared in terms of damping capability. Finally, simulation and experimental results are provided in order to validate the proposed functionalities of the DG control system

Broadband terahertz pulse generation driven by an ultrafast thin-disk laser oscillator

We demonstrate broadband THz generation driven by an ultrafast thin-disk laser (TDL) oscillator. By optical rectification of 50-fs pulses at 61 MHz repetition rate in a collinear geometry in crystalline GaP, THz radiation with a central frequency at around 3.4 THz and a spectrum extending from below 1 THz to nearly 7 THz are generated. We realized a spectroscopic characterization of a GaP crystal and a benchmark measurement of the water-vapor absorption spectrum in the THz range. Sub-50-GHz resolution is achieved within a 5 THz bandwidth. Our experiments show the potential of ultrafast TDL oscillators for driving MHz-repetition-rate broadband THz systems

Contribuições para a teoria de potencias instantaneas e aplicações em qualidade de energia

Orientador: Sigmar Maurer DeckmannDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Os recentes trabalhos envolvendo Teorias de Potências Instantâneas têm sido amplamente utilizados na elaboração de técnicas de análise de distúrbios elétricos e controle de dispositivos de condicionamento de energia. Tais teorias têm se mostrado bastante eficazes, particularmente no caso trifásico, no entanto restam algumas dúvidas ou discussões que ainda necessitam de estudos para que soluções definitivas sejam encontradas para casos gerais.O principal objetivo deste trabalho é apresentar duas decomposições de sinais temporais, as quais levam a uma alternativa interessante para o estudo das grandezas elétricas, de forma que permitem a identificação de várias parcelas distintas de tensão, corrente e potência, associando cada uma ao fenômeno físico responsável por sua origem. Espera-se portanto, que as decomposições e a metodologia de cálculo das componentes de potência instantânea apresentadas neste trabalho contribuam para que se encontre uma Teoria de Potências o mais geral e didática possível. Sobre as decomposições, uma permite encontrar a mínima corrente necessária para suprir a potência útil requerida pelas cargas do sistema elétrico, e pode ser aplicada a qualquer tipo de sinal temporal, independentemente de periodicidade, forma de onda, simetria ou número de variáveis. A outra por sua vez, permite separar as parcelas de tensão, corrente e potência de freqüências fundamentais, dos sinais responsáveis por distorção na forma de onda destas grandezas, o qual denominou-se resíduo dos sinais.N o âmbito de qualidade de energia, assunto de extrema importância na recente reformulação do setor elétrico mundial, acredita-se que as definições e discussões tratadas ao longo deste trabalho, possam auxiliar em diversas aplicações para manutenção e monitoração da qualidade da energia elétricaAbstract: Instantaneous Power Theories have been widely exploited for electrical disturbance analysis and control applied to power conditioning equipment. These theories have shown to be very promising, particularly in the three-phase case, however several questions still require more researches to find definitive solutions in general cases.The main objective of this work is to present two time signal decomposition techniques, which consti-tute an interesting alternative to study electrical signals, allowing to identify voltage, current, and power components, associating each one with the corresponding physical phenomenon responsible for it. The signal decompositions and calculation methodologies presented in this work are intended to contribute for a more comprehensive Power Theory.About the two decompositions, the first one allows to find the minimum current needed to supply the active power required from electrical system loads, and it can be applied to any time function, independently of period, waveform, symmetry, or variables number. The second one allows splitting voltages, currents and power signals into fundamental waves and signals with harmonic and inter-harmonic frequencies. This last part is responsible for waveform distortions of the signals and it was named residual signal.Concerning power quality, a subject of extreme interest in the recent reformulation of worldwide electrical utilities, the definitions and discussion presented in this work are expected to be useful for several applications in order to maintain and monitor the electric power qualityMestradoMestre em Engenharia Elétric