O avanço crescente da tecnologia nos processos industriais atuais, bem como o elevado grau de interação de equipamentos e processos, provocou o aumento da sua sensibilidade a variações de energia, ou o aumento do grau de sensibilidade de algumas cargas industriais, o que gera interrupções de produção industrial. Essas, ocasionadas por problemas de qualidade de energia, levam a diversos fatores indesejáveis às indústrias, tais como: perdas de produção, perdas de faturamento, perda de matéria-prima, uso irracional de energia, dentre outros. Um processo têxtil apresenta grandes perdas de produção quando ocorrem esses eventos. Esta dissertação apresenta uma série seqüencial de procedimentos técnicos adotados experimentalmente em duas plantas de fiação sintética, para mitigar o impacto da qualidade de energia numa indústria química-têxtil. O problema de qualidade de energia estudado foi a variação de tensão de curta duração (VTCD), especificamente os afundamentos de tensão, sobre uma carga crítica. Quando esses eventos ocorriam, havia um grande volume de perdas no processo, em função da descontinuidade operacional provocada por esses afundamentos de tensão. Por meio de procedimentos foi possível identificar a carga crítica, no caso, os conversores estáticos de freqüência utilizados amplamente nesse processo. Uma vez identificada essa carga, foi possível a realização de intervenções objetivando reduzir a sua sensibilidade. Dois experimentos realizados através de um painel que simulou a situação do processo, com testes de afundamentos de tensão em conversores estáticos de freqüência, além de outros trabalhos experimentais utilizados como referências nessa dissertação, serviram como complemento para a conclusão. As intervenções realizadas tiveram como conseqüência a melhoria de qualidade do produto, aumento da produtividade, além de grande retorno financeiro. / The increasing evolution of technology in the current industrial processes, as well as the high interaction degree of equipment items and processes, have caused the increase in their sensitivity to voltage variations. The increase of sensitivity in some industrial loads generates interruptions in the industrial production. That happens due to power quality problems, which causes many undesired effects to the industries, such as losses in production, invoicing and raw material, unreasonable use of energy, among others. A textile process presents large production losses whenever these events in the process occur. This dissertation presents a sequence of technical procedures adopted experimentally in two yarn plants, to mitigate and reduce the impact of power quality problems in the chemical textile plant. The problem of power quality studied was short duration voltage variations, specifically the voltage sags. These events lead to a big volume of loss in the process, by operational disruption of sensitivity loads provoked by the voltage sags. By means of the proposed procedures it was possible to identify the critical load, in this case the ASD (Adjustable Speed Drive), a kind of load used extensively in the textile process; once identified this load, it was possible to carry out interventions aiming at the reduction of loads sensitivities. Two experiences were realized through a panel that simulated the process, by applying voltage sags to the drivers - ASD (Adjustable Speed Drive). Besides that other research works surveyed to complement and conclude this dissertation. The interventions realized have had as consequence the improvement in the product quality, increasing productivity, as well as an excellent payback.

Este trabalho apresenta uma metodologia de detecção e classificação de distúrbios relacionados à qualidade da energia elétrica. A detecção é feita utilizando-se somente uma regra para inferir na presença ou não do distúrbio em uma janela analisada. Para a classificação é proposto um método baseado em árvore de decisão. A árvore recebe como entrada as características do sinal extraídas tanto no domínio do tempo como no domínio da frequência, sendo a última obtida pela Transformada de Fourier. Destaca-se que toda a metodologia de extração de características foi idealizada como tentativa de se reduzir ao máximo o esforço computacional das tarefas de detecção e classificação de distúrbios. Em suma, verifica-se que os resultados obtidos são satisfatórios para a proposta desta pesquisa. / This work presents a methodology for detection and classification of disturbance related to the electric power quality. The detection is performed using only one rule to infer in the presence or not of the disturbance in a window analyzed. For the classification is proposed a method based on decision tree. The tree receives as input features of the extracted signal both in time domain and in the frequency domain, being the last obtained by Fourier transform. It is emphasized that all the features extraction methodology was idealized as an attempt to reduce to the maximum the computational effort for the tasks of detection and classification of disturbances. In short, it is possible to verify that the results obtained are satisfactory for the purpose of this research.

Made available in DSpace on 2017-07-10T16:04:57Z (GMT). No. of bitstreams: 1 Dissertacao __Unioeste 2015.pdf: 1958524 bytes, checksum: e270c5e92a72bff17ae88d8945fb8603 (MD5) Previous issue date: 2015-11-23 / The industrial production of Paraná state is diverse with emphasis on the industries of pulp and paper, timber, food, chemical, fertilizer, electronics, metalworking, cement, textile, ceramic and linked to its rural vocation, agribusiness . An adequate infrastructure enforces the competitiveness of the industry and the lack of this may undermine the state's economy. This study examined the effects of lack of harmony or mismatch between what is expected and what is actually offered for Paraná industries by analyzing one of the main inputs needed in basic infrastructure to support production, which is the energy supply power quality, focusing on aspects related to quality of service. The distribution of electricity is a public service activity, rather regulated and due to its nature, characterized as a legal monopoly, therefore industries have no alternative supplier for replacement. This paper is Subsidized by information prospected in research conducted with 23 Paraná industrial consumers of various segments of activities, which have recent records of complaints about the quality of energy supply filed with the distribution concessionaire or the regulator. On the one hand the offer represented by the distribution company's vision of energy, on the other hand the demand vision represented by consumers of electricity industries and mediating these relationships the National Electric Energy Agency - ANEEL. The work was completed with purposeful actions to mitigate conflicts between parties. Preventive strategies have been formulated to the problem, they propose as a tool that could contribute to the alignment of perceptions between the parties. The listed actions are aimed at harmonizing the relationships and expectations among industrial business and the power distributor, bringing contributions to competitiveness of the product which is manufactured in the state. / A produção industrial do estado do Paraná é diversificada com destaque para as indústrias de papel e celulose, madeireira, alimentícia, química, fertilizantes, eletroeletrônica, metalmecânica, cimento, têxtil, cerâmica e vinculada à sua vocação rural, a agroindústria. Uma infraestrutura adequada é fator de impulso à competitividade das indústrias e a falta desta pode comprometer a economia do estado. O presente trabalho analisou os efeitos da falta de sintonia ou do descompasso entre o que é esperado e o que realmente é ofertado para as indústrias do Paraná ao se analisar um dos principais insumos necessários na infraestrutura básica de suporte à produção, que é a oferta da energia elétrica de qualidade, com enfoque nos aspectos relacionados à qualidade do serviço. A distribuição de energia elétrica é uma atividade de utilidade pública, bastante regulada e devido a sua natureza, caracterizada como um monopólio legal, as indústrias não possuem alternativas para substituição de fornecedor. Subsidia este trabalho as informações prospectadas em pesquisa efetuada com 23 consumidores industriais paranaenses de variados segmentos de atividades, que possuem registros recentes de reclamações sobre a qualidade do fornecimento da energia, protocolados na concessionária de distribuição ou no órgão regulador. De um lado, a oferta representada pela visão da empresa distribuidora de energia, de outro lado, a visão da demanda representada pelas indústrias insumidoras de eletricidade e mediando estas relações a Agência Nacional de Energia Elétrica ANEEL. O trabalho foi concluído com ações propositivas para a mitigação de conflitos entre as partes envolvidas. Foram formuladas estratégias preventivas para o problema, que se propõem como instrumento que poderá contribuir para o alinhamento das percepções entre as partes. As ações elencadas visam melhor harmonizar as relações e expectativas entre empresariado industrial e a distribuidora de energia, trazendo contribuições para competitividade do produto que é manufaturado no Estado.

Esta Tese trata do controle e integração de centrais eólicas à rede elétrica interligada, utilizando-se geradores de indução duplamente alimentados (GIDE). O objetivo principal da Tese foi desenvolver estratégias de controle discreto para o sistema de geração eólica, de forma a reduzir os impactos na qualidade da energia gerada, em função dos diversos regimes e transitórios de vento, que podem ocorrer no sítio eólico. Para o projeto do sistema de controle dos geradores foi adotada a técnica do controle vetorial, de forma a desacoplar o controle do fluxo das potências ativa e reativa entre o gerador e a rede elétrica. Visando caracterizar os diversos modos de operação do GIDE, com velocidades acima e abaixo da síncrona, foi desenvolvido um estudo de regime permanente do gerador, obtendo-se os limites de correntes, tensões e demais grandezas elétricas e mecânicas, para uma determinada faixa de velocidade. As principais estratégias de controle atualmente utilizadas pelos fabricantes de turbinas eólicas foram analisadas, destacando-se os aspectos da eficiência energética do conjunto turbina-gerador e da qualidade da energia. O projeto das malhas de controle dos conversores estáticos conectados ao circuito do rotor foi desenvolvido utilizando a técnica de controle discreto, propondo-se as estratégias de controle e o conjunto de especificações para definição dos ganhos dos controladores, objetivando reduzir os impactos na qualidade da energia gerada. Foi analisada a influência da modelagem da turbina com eixos elásticos e eixos rígidos, no comportamento das variáveis controladas. Buscando reduzir os harmônicos de ordem elevada da corrente do gerador, devido à modulação por largura de pulso (PWM) dos conversores estáticos, foi proposta uma estratégia de projeto de filtro passivo LCL, instalado no circuito do rotor. Um programa de simulação no ambiente Matlab/Simulinkâ foi desenvolvido, para análise da interligação de um parque eólico, representado por uma turbina equivalente, ao sistema elétrico de potência reduzido, permitindo estudos de regime permanente e transitório. Com este programa, um estudo de caso foi realizado, avaliando-se o controle e a integração de uma usina eólica de 192MW, conectada na rede básica do sistema interligado nacional, na tensão 230kV. Os resultados obtidos mostram as contribuições, das estratégias de controle propostas, para melhorar o comportamento das tensões do sistema elétrico quando da ocorrência de transitórios de ventos na usina. / This Thesis presents the control and integration of wind farms to the interconnected power grid, using doubly fed induction generators (DFIG). The main objective of the present Thesis was to develop discrete control strategies for the wind generation system, with the goal to reduce the wind variations impacts in the grid power quality. The design technique selected for the generators control system was the vector control technique, which allows independent control of active and reactive power flow between the generator and the grid. In order to characterize the diverse operation modes of the DFIG, below and above the synchronous speed, a generator steady-state study was developed, getting the current and voltage limits and the others electric and mechanical safe limits variables, for one determined speed range. The main control strategies currently used by the wind turbines manufacturers were analyzed, highlighting the aspects of the turbine-generator energy efficiency and the power quality. The control loops design of the static converters was developed using the discrete control technique. It was elaborated the control strategies and also the basic specifications used to define the controllers gains, with the key target to reduce the impacts in the grid power quality caused by the wind variations. Other aspect covered by this work was the influence of the turbine modeling, with rigid shafts and with shafts of a relatively low stiffness, in the control system performance. In a way to reduce high order harmonics in the generator current, caused by the pulse width modulation (PWM) of the static converters, it was proposed a design strategy of a passive LCL filter, installed in the rotor circuit. A simulation program was developed, using the Matlab/SimulinkÔ platform, to analyze the interconnection of a wind farm, represented by a equivalent turbine, to the reduced power electrical system, allowing steady-state and transient studies. With this simulation program, a case study was developed evaluating the control and integration of a 192MW wind farm, connected to 230kV voltage level of the national interconnected power system. The main results reached by this work showed the contributions of the control strategies proposed to improve the electrical system voltages behavior, when wind variations occur in the wind farm.

Os medidores de energia elétrica estão deixando de ser simples instrumentos de aplicação dedicada para se tomarem instrumentos extremamente funcionais. Desde a sua invenção, os medidores vêm sofrendo alterações de acordo com os recursos tecnológicos da época e as exigências de mercado. Atualmente, os processadores digitais de sinais têm sido amplamente empregados nesta área, permitindo a integração de uma série de funções em um único equipamento, além da implementação de algoritmos mais complexos. Estas funções geralmente incluem o cálculo de uma variedade de parâmetros elétricos, comunicação remota, integração com sistemas digitais e outras. Este trabalho apresenta um estudo e o desenvolvimento de um medidor de energia elétrica baseado no processador digital de sinais DSP56002 da Motorola. Entre as funções que são incorporadas ao medidor, destaca-se o monitoramento da qualidade da energia elétrica, visto que esta será uma tendência futura. / Electric energy meters have been changing from simple instruments for dedicated applications to very functional ones. Since their invention, the meters has changed accordingly to the technology resources and market requirements. Nowadays, the digital signal processors have been widely employed in this area, allowing a huge amount of functions to be integrated into only one instrument, besides of the implementation of more complex algorithms. Such functions usually include evaluation of many electrical parameters, remote communication, connection to digital systems and others. This work is about a study and a development of an electric energy meter based on the digital signal processor DSP56002 by Motorola. Among the functions that are incorporated to the meter, it points out the monitoring of electric power quality, once it will be a future trend.

Com o déficit de energia que atualmente preocupa o setor elétrico brasileiro, ameaçando os consumidores com a possibilidade de novos racionamentos, surge a perspectiva de aumento de produção de energia, através da criação de usinas eólicas para suprir essa demanda. Entretanto, esta forma de geração, sabidamente, provoca distorções na qualidade de energia fornecida, principalmente quanto à geração de harmônicas, que acabam por interferir diretamente nas cargas podendo provocar danos a equipamentos e instalações. Por esse motivo, este trabalho visa analisar a contribuição desse tipo de geração no sistema elétrico e discutir, com base em estudos experimentais realizados em modelos de aerogeradores e diretamente em unidades geradoras instaladas em plantas de geração eólica, as perturbações harmônicas geradas pelo controle de tensão e frequência do sistema. A metodologia utilizada será a de medição das distorções harmônicas, através de analisadores de qualidade de energia, instalados primeiramente em modelos laboratoriais dos principais tipos de aerogeradores existentes no mercado, medindo as perturbações em diversas situações de carga, obedecendo ao estabelecido na norma NBR-IEC- 61400-21/2010 Medição e Avaliação da Qualidade de Energia de Aerogeradores Conectados a Rede. / With the energy deficit that currently worries the Brazilian electric sector, threatening consumers with the possibility of further rationing comes the prospect of increased energy production through the creation of wind farms to meet this demand. However, this form of generation is known to distort the quality of power supplied, especially as the generation of harmonics, which ultimately interfere directly in the loads can cause damage to equipment and facilities. Therefore, this study aims to analyze the contribution of this type of generation on the electrical system and discuss, based on experimental studies in directly generating units installed in wind generation plants, disturbances generated by harmonic voltage and frequency control system. The methodology will be the measurement of harmonic distortion through power quality analyzers, installed primarily in laboratory models of the main types of wind turbines on the market, measuring disturbances in various loading conditions, obeying the established standard NBR-IEC-61400-21/2010 - Measurement and Evaluation of Power Quality of Wind Turbines Connected Network.

The thesis deals with the application of compensators andswitches based on power electronics in AC transmission anddistribution systems. The objective of the studieddevices/equipment is the power flow and voltage control intransmission systems and the mitigation of voltage sags andmomentary interruptions to critical loads in distributionsystems. For validating the power electronics based devices/equipmentdescribed in the thesis, scaled models at a real-time simulatorhave been built. Simulation results of these models arepresented and discussed in the thesis. The equipment studied in the thesis exploit the fast controlactions that can be taken by power electronics devices, whichare much faster than the speed of conventional equipment andprotection systems, based on electromechanical devices. In thisway, the power quality of distribution systems is improved,regarding duration and magnitude of voltage sags (dips) andmomentary interruptions, which are the most relevant types ofdisturbances in distribution systems. The thesis presents some compensators based onforced-commutation voltage-source converters for correctingvoltage sags and swells to critical loads. The seriesconverter, usually denoted Dynamic Voltage Restorer (DVR), hasbeen proved suitable for the task of compensating voltage sagsin the supply network. The use of solid-state devices ascircuit breakers in distribution systems has also been studiedwith the objective of achieving fast interruption or limitationof fault currents. The location and practical aspects for theinstallation of these solid-state breakers are presented. Ithas beenshown that a configuration based on shunt and seriesconnected solid-state devices with controllable turn-offcapability can also provide voltage sag mitigation, without theneed of transformers and large energy storage elements. The operation and control of two Flexible AC TransmissionSystem (FACTS) devices for voltage and power flow control intransmission systems, namely the Static Synchronous Compensator(STATCOM) and the Unified Power Flow Controller (UPFC),respectively, are also studied. A faster response compared totraditional equipment consisting of mechanically based/switchedelements is then achieved. This allows a more flexible controlof power flow and a secure loading of transmission lines tolevels nearer to their thermal limits. The behaviour of thesedevices during faults in the transmission system is alsopresented. Keywords: power electronics, power quality, voltagesags, voltage-source converters, Custom Power, FACTS, real-timesimulations, solid-state devices.

During the last decade, power quality has been recognised asa global problem. Among different types of power qualityproblems, voltage sags have been identified to be one of themost severe problems for different process industries. The mostcommon reason to voltage sags is lightning strikes in powerlines. Protection equipment, usually located at switchyards,disconnect faulted power lines as soon as possible, which isapproximately 100 ms. Thus, the duration of voltage sags areapproximately 100 ms. The sensitivity to voltage sags ofelectrical equipment in process industries can be observed asfor instance malfunction, automatic turnoff or damages. This thesis gives an overview of three metals processes withfocus on the sensitivity to voltage sags and interruptions. Theinherent energy in the process is used to find the sensitivity.This energy may also be used to obtain "ride-through" for theprocesses. The three metals processes are a blast furnaceprocess, a hot rolling mill process and a cold rolling millprocess. The main attention in this thesis is paid to the blastfurnace process, which is powered by a line-operatedsynchronous machine. The thesis shows that the protection equipment forelectrical machines can be adjusted to avoid unnecessaryshutdowns. It is also explained why there are high torque andcurrents during voltage sags as well as after voltage sags. Itis shown that the first peak torque and current during thevoltage sags is almost proportional to the voltage change, thatis the voltage magnitude before the voltage sag minus thevoltage magnitude during the voltage sag. The first peak torqueand current after the voltage sag depends sinusoidal-like onthe duration of the voltage sag and almost proportional to thevoltage change during the voltage sag. There is no fluxsaturation during voltage sags, however after voltage sagssaturation is very likely to occur. The thesis explains why andalso how the flux is changed during and after voltage sags. The duration of voltage sags is in many cases set by theprotection equipment located in switchyards. It is shown thatthe durations of voltage sags can be changed to durations thatwill cause less peak torque and current after voltage sags forline-operated AC-machines. It is also shown how this istheoretically achieved. <b>Keywords:</b>Rolling mill, Blast furnace, Power Quality,Synchronous machine, Asynchronous machine, Voltage sag, Voltageinterruption, Ride-through, Process disturbances, Simulation,Modelling

The main bulk of electric power systems use a three¿phase configuration with an alternating current flow. Pursuing the optimal performance of these networks and avoiding possible technical problems, it is preferred balanced operating conditions, i.e., the currents of all phases have the same magnitude and form a direct sequence with a phase of 120º. However, if several single¿phase loads (such as high speed traction systems) are present in these systems, the operating condition turns unbalanced, provoking an asymmetric voltage supply. This undesirable working condition can be avoided by the use of two reactances connected with the single-phase load using a triangle configuration, in such a way that the total current consumption turns out to be balanced. This approach is commonly known as Steinmetz circuit or symmetrizing circuit. Due to the reactances of the symmetrizing circuit, the connection of the circuit in an electric network changes the system frequency response, appearing new resonances of several types and presenting impedance values too small or too large. Moreover, the quantity of nonlinear loads (i.e., loads with consume nonsinusoidal currents, such as arc furnaces, power electronics devices like high-speed rail systems...) is increasing nowadays. The harmonic current injection by these charges may interact with the resonances caused by the Steinmetz circuit, resulting in a large harmonic distortion in voltage. The aim of this doctoral thesis is to analyze the presence of several types of resonances in order to avoid this problem. It is used a simplified scheme of a network in which the single¿phase load and the symmetrized circuit are connected. This system also encloses nonlinear loads that generate harmonic currents. This set is analyzed from the viewpoint of nonlinear loads and of the network for parallel and series resonance frequencies location, respectively. By obtaining these resonant frequencies and knowing the harmonic injection of nonlinear loads, the trouble of voltage supply distortion can be anticipated and avoided.

This report seeks to evaluate and predict possible power quality issues regarding Fortums engagement in the project of Stockholm Royal Seaport. Stockholm Royal Seaport is a city district planned by Stockholm Municipality to be constructed based on sustainable urban city principles. Fortum has, together with additional partners, engaged in the challenge to create a sustainable energy system. This is thought to be achieved through several measures. Energy saving actions are incorporated at several levels and there is a plan to create a “smart grid” for the electricity supply. A smart grid has no strict definition but in this case a key feature is “demand-response” which effectively means a way to optimize the consumption to have a more balanced consumption over the 24 hours of a day. One of the key components in the smart grid is the “active house” which is planned to have several specific features separating it from an ordinary house. It is planned to have its own contribution to electricity production using solar cells and an energy storage using batteries. Another feature is thought to be both automation and economic incentives measures to achieve peak load reduction. This thesis has taken the perspective of the end customer in the active house and has tried to evaluate the power quality to be experienced. An investigation regarding the different components has been carried out to get an overview from the mentioned perspective and identify possible problems or issues that may require attention in the realization of Stockholm Royal Seaport. It has been found that no major problems are to be expected but some smaller issues has arisen that might be worthwhile giving some attention.