A opção por sistemas biológicos prevalece para o tratamento do esgoto sanitário. Nas décadas recentes, sistemas que possuem regiões e/ou zonas anaeróbia, anóxica e aeróbia têm-se mostrado como alternativas atraentes para remoção simultânea de matéria orgânica, nitrogênio e fósforo. No entanto, os aspectos operacionais ainda merecem ser objeto de estudo para alcançar desempenho otimizado. Nesse cenário, com intuito de comparar alternativas para a operação das unidades de tratamento de esgoto, o presente trabalho propôs-se a estudar estratégias operacionais associadas ao monitoramento, em tempo real, sem adição de fonte externa de carbono, para um reator aerado não compartimentado com crescimento suspenso e fluxo contínuo precedido de reator anaeróbio. O sistema experimental, em escala de bancada, era constituído de um reator anaeróbio, com volume útil de 43,54 L, e reator aerado, com volume útil de 68,07 L; sendo que este era formado por sete setores, em série, sem separação física. O estudo foi dividido em duas etapas: I - estudo da variação dos volumes da região aerada e da não aerada; II - estudo da aeração intermitente com ciclo de aeração/agitação pré-fixado e controlado em tempo real por sistema informatizado. Em todas as Etapas do estudo ocorreu elevada remoção de DBO e conversão de NTK para nitrato, contudo não se conseguiu obter desnitrificação em nível desejado. O uso de reatores com setores sequenciais sem divisão física (Etapa I) dificultou a obtenção de regiões distintas predominantemente anóxica e aeróbia, comprometendo a remoção de nitrogênio (principalmente a desnitrificação). A maior eficiência média de remoção de nitrogênio alcançada no reator aerado foi de 35,6% (Etapa II), quando o reator era operado com aeração intermitente sendo o ciclo de aeração/agitação controlado em tempo real. A estratégia de operação com aeração intermitente, estudada na Etapa II, favoreceu a remoção de nitrogênio. A aeração intermitente demonstrou ser uma opção promissora comparada à aeração contínua em setores específicos do reator. O controle automatizado e informatizado em tempo real dos ciclos de aeração/agitação pode ser aplicado no aperfeiçoamento da operação dos sistemas de tratamento de esgoto sanitário. / The option of biological systems prevails for the treatment of sewage waste and in recent decades, systems that have anaerobic, anoxic, aerobic regions and / or zones have proven attractive for simultaneous removal of organic matter, nitrogen and phosphorus. However, the operational aspects still deserve to be studied in order to achieve the optimized performance of these systems. In this scenario, in order to compare alternatives for the operation of sewage treatment plants, the present work aimed to study operational strategies associated with monitoring, in real time, without the addition of external carbon source, for a non-compartmentalized aerated reactor with growth suspended and continuous flow preceded by anaerobic reactor. The experimental system in bench scale consisted of an anaerobic reactor, with a volume of 43.54 L and an aerated reactor, with a volume of 68.07 L; consisting of seven sectors, in series, without physical separation. The study was divided into two stages: I - study of the variation of the volume of the aerated and non-aerated regions; II - study of intermittent aeration with cycle of aeration/agitation controlled by a pre-fixed time interval; and controlled in real time by a computerized system. In all Stages of the study high BOD removal and conversion of TKN to nitrate occurred, but were unable to obtain denitrification at desired level. The use of reactors with sequential sectors without physical division (Stage I) made it difficult to obtain predominantly distinct anoxic and aerobic regions, compromising the removal of nitrogen (mainly the denitrification). The highest average removal efficiency of nitrogen attained in aerated reactor was 35.6% when the reactor was operated with intermittent aeration with aeration cycle controlled in real time. The operation strategy with intermittent aeration, studied in Stage II, favored the removal of nitrogen. The intermittent aeration proved to be a promising option compared to continuous aeration in specific sectors of the reactor. The automated and computerized control in real-time of the aeration / agitation cycles can be applied in improving the operation of sewage waste treatment systems.

This thesis describes an investigation into the influences of arcing and conductor deflection due to magnetic forces on the accuracy of fault locator algorithms in electrical distribution networks. The work also explores the possibilities of using the properties of an arc to identify two specific types of faults that may occur on an overhead distribution line. A new technique using the convolution operator is introduced for deriving differential equation algorithms. The first algorithm was derived by estimating the voltage as an array of impulse functions while the second algorithm was derived using a piecewise linear voltage signal. These algorithms were tested on a simulated single-phase circuit using a PI-model line. It was shown that the second algorithm gave identical results as the existing dynamic integration operator type algorithm. The first algorithm used a transformation to a three-phase circuit that did not require any matrix calculations as an equivalent sequence component circuit is utilised for a single-phase to ground fault. A simulated arc was used to test the influence of the non-linearity of an arc on the accuracy of this algorithm. The simulations showed that the variation in the resistance due to arcing causes large oscillations of the algorithm output and a 40th order mean filter was used to increase the accuracy and stability of the algorithm. The same tests were performed on a previously developed fault locator algorithm that includes a square-wave power frequency proximation of the fault arc. This algorithm gave more accurate and stable results even with large arc length variations. During phase-to-phase fault conditions, two opposing magnetic fields force the conductors outwards away from each other and this movement causes a change in the total inductance of the line. A three dimensional finite element line model based on standard wave equations but incorporating magnetic forces was used to evaluate this phenomenon. The results show that appreciable errors in the distance estimations can be expected especially on poorly tensioned di stribution lines.New techniques were also explored that are based on identification of the fault arc. Two methods were successfully tested on simulated networks to identify a breakingconductor. The methods are based on the rate of increase in arc length during the breaking of the conductor. The first method uses arc voltage increase as the basis of the detection while the second method make use of the increase in the non-linearity of the network resistance to identify a breaking conductor. An unsuccessful attempt was made to identifying conductor clashing caused by high winds: it was found that too many parameters influence the separation speed of the two conductors. No unique characteristic could be found to identify the conductor clashing using the speed of conductor separation. The existing algorithm was also used to estimate the voltage in a distribution network during a fault for power quality monitoring purposes.

Switching of shunt reactors and capacitor banks is known to cause a very high rate of rise of transient recovery voltage across the circuit breaker contacts. With improvements in circuit breaker technology, modern SF6 puffer circuits have been designed with less interrupter per pole than previous generations of SF6 circuit breakers. This has caused modern circuit breakers to operate with higher voltage stress in the dielectric recovery region after current interruption. Catastrophic failures of modern SF6 circuit breakers have been reported during shunt reactor and capacitor bank de-energisation. In those cases, evidence of cumulative re-strikes has been found to be the main cause of interrupter failure. Monitoring of voltage waveforms during switching would provide information about the magnitude and frequency of small re-ignitions and re-strikes. However, measuring waveforms at a moderately high frequency require plant outages to connect equipment. In recent years, there have been increasing interests in using RF measurements in condition monitoring of switchgear. The RF measurement technique used for measuring circuit breaker inter-pole switching time during capacitor bank closing is of particular interest. In this thesis, research has been carried out to investigate switching transients produced during circuit breaker switching capacitor banks and shunt reactors using a non-intrusive measurement technique. The proposed technique measures the high frequency and low frequency voltage waveforms during switching operations without the need of an outage. The principles of this measurement technique are discussed and field measurements were carried out at shunt rector and capacitor bank installation in two 275 kV air insulated substations. Results of the measurements are presented and discussed in this thesis. The proposed technique shows that it is relatively easy to monitor circuit breaker switching transients and useful information on switching instances can be extracted from the measured waveforms. Further research works are discussed to realise the full potential of the measuring technique.

Made available in DSpace on 2016-08-17T14:53:13Z (GMT). No. of bitstreams: 1 Newton_ Teixeira _do_ Nascimento Junior.pdf: 3217306 bytes, checksum: c4c1a1e0f923de4227056ce0050d06f8 (MD5) Previous issue date: 2010-10-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This paper presents a computational method to monitor the operating state of steady electric power transformers in a real time and perspectives of operation over time trends and their operation. The methodology consists of two main steps. The first step is building composed of a block of fuzzy inference s block that can monitor real-time values of transformer s electrical parameters of the transformer (current, voltage between phases, power, oil temperature, winding temperature), to analyze and map these inputs into a single output that reflects what has been defined as operational status of the transformer. We defined five regions of transformer s operation by which a processor can work: emergency, urgent, warning, stable and great. The second step analyze the trend of increase / decrease of operating state obtained from the fuzzy block in a given period, as one day, a month, one year and / or several years. This trend can be characterized in various ways, such as increasing, decreasing very constant. Statistical methods are employed for this analysis. The methodology was evaluated on a database of a large company of generation and transmission of electric energy from the Brazilian electricity sector. The results were satisfactory in that the development of operation of such equipment was qualitatively mapped and their tendencies well characterized. Conceptually, the analytical model presented can be extended to multiple processing units, electric and other functions for up to a full network of interest, allowing subsidize the operation of this and can indicate the need for any future system reinforcements. / Este trabalho apresenta uma metodologia computacional para monitorar o estado operacional em regime permanente de transformadores de potência elétrica ao longo do tempo e suas respectivas tendências de operação. A metodologia é composta de duas etapas principais. Na primeira etapa é construído um bloco de inferência fuzzy capaz de monitorar em tempo real os valores de variáveis elétricas do transformador (corrente, tensão entre fases, potência, temperatura do óleo e temperatura dos enrolamentos), analisar e mapear estas entradas em uma única saída que reflete o que foi definido como estado operacional do transformador. Foram definidas cinco regiões de operação pelas quais um transformador pode trabalhar: emergência, urgência, advertência, estável e ótimo. A segunda etapa trata de analisar a tendência crescimento/decrescimento desse estado operativo obtido do bloco fuzzy em um determinado período, tal como um dia, um mês, um ano e/ou vários anos. Essa tendência pode ser caracterizada de várias formas, tais como crescente, muito decrescente, constante. Métodos estatísticos são empregados para realizar essa análise. A metodologia foi avaliada com uma base de dados de uma grande empresa geradora e transmissora de energia do setor elétrico brasileiro. Os resultados alcançados foram satisfatórios, na medida em que a evolução de operação desses equipamentos foi qualitativamente mapeada e suas tendências bem caracterizadas. Conceitualmente, o modelo de análise apresentado pode ser estendido para várias unidades transformadoras, para outras funções elétricas e até para uma rede de interesse completa, permitindo subsidiar a operação desta e dar indicativos de necessidade de reforços futuros no sistema.

A opção por sistemas biológicos prevalece para o tratamento do esgoto sanitário. Nas décadas recentes, sistemas que possuem regiões e/ou zonas anaeróbia, anóxica e aeróbia têm-se mostrado como alternativas atraentes para remoção simultânea de matéria orgânica, nitrogênio e fósforo. No entanto, os aspectos operacionais ainda merecem ser objeto de estudo para alcançar desempenho otimizado. Nesse cenário, com intuito de comparar alternativas para a operação das unidades de tratamento de esgoto, o presente trabalho propôs-se a estudar estratégias operacionais associadas ao monitoramento, em tempo real, sem adição de fonte externa de carbono, para um reator aerado não compartimentado com crescimento suspenso e fluxo contínuo precedido de reator anaeróbio. O sistema experimental, em escala de bancada, era constituído de um reator anaeróbio, com volume útil de 43,54 L, e reator aerado, com volume útil de 68,07 L; sendo que este era formado por sete setores, em série, sem separação física. O estudo foi dividido em duas etapas: I - estudo da variação dos volumes da região aerada e da não aerada; II - estudo da aeração intermitente com ciclo de aeração/agitação pré-fixado e controlado em tempo real por sistema informatizado. Em todas as Etapas do estudo ocorreu elevada remoção de DBO e conversão de NTK para nitrato, contudo não se conseguiu obter desnitrificação em nível desejado. O uso de reatores com setores sequenciais sem divisão física (Etapa I) dificultou a obtenção de regiões distintas predominantemente anóxica e aeróbia, comprometendo a remoção de nitrogênio (principalmente a desnitrificação). A maior eficiência média de remoção de nitrogênio alcançada no reator aerado foi de 35,6% (Etapa II), quando o reator era operado com aeração intermitente sendo o ciclo de aeração/agitação controlado em tempo real. A estratégia de operação com aeração intermitente, estudada na Etapa II, favoreceu a remoção de nitrogênio. A aeração intermitente demonstrou ser uma opção promissora comparada à aeração contínua em setores específicos do reator. O controle automatizado e informatizado em tempo real dos ciclos de aeração/agitação pode ser aplicado no aperfeiçoamento da operação dos sistemas de tratamento de esgoto sanitário. / The option of biological systems prevails for the treatment of sewage waste and in recent decades, systems that have anaerobic, anoxic, aerobic regions and / or zones have proven attractive for simultaneous removal of organic matter, nitrogen and phosphorus. However, the operational aspects still deserve to be studied in order to achieve the optimized performance of these systems. In this scenario, in order to compare alternatives for the operation of sewage treatment plants, the present work aimed to study operational strategies associated with monitoring, in real time, without the addition of external carbon source, for a non-compartmentalized aerated reactor with growth suspended and continuous flow preceded by anaerobic reactor. The experimental system in bench scale consisted of an anaerobic reactor, with a volume of 43.54 L and an aerated reactor, with a volume of 68.07 L; consisting of seven sectors, in series, without physical separation. The study was divided into two stages: I - study of the variation of the volume of the aerated and non-aerated regions; II - study of intermittent aeration with cycle of aeration/agitation controlled by a pre-fixed time interval; and controlled in real time by a computerized system. In all Stages of the study high BOD removal and conversion of TKN to nitrate occurred, but were unable to obtain denitrification at desired level. The use of reactors with sequential sectors without physical division (Stage I) made it difficult to obtain predominantly distinct anoxic and aerobic regions, compromising the removal of nitrogen (mainly the denitrification). The highest average removal efficiency of nitrogen attained in aerated reactor was 35.6% when the reactor was operated with intermittent aeration with aeration cycle controlled in real time. The operation strategy with intermittent aeration, studied in Stage II, favored the removal of nitrogen. The intermittent aeration proved to be a promising option compared to continuous aeration in specific sectors of the reactor. The automated and computerized control in real-time of the aeration / agitation cycles can be applied in improving the operation of sewage waste treatment systems.

Se desarrolló cinco sistemas automatizados utilizando análisis por inyección secuencial (SIA) y análisis por inyección en flujo multijeringa (MSFIA). Se desarrolló un SI-analizador para la determinación de formaldehído utilizando la reacción de Hantzsch. El analizador fue aplicado a la monitorización en un cultivo de P. pastoris. Se desarrolló un SI-analizador para la determinación de glicerol y sorbitol. Se utilizó periodato para la reacción de Malaprade. El formaldehído generado fue cuantificado con la reacción de Hantzsch. El sistema incluyó la dilución de la muestra y procedimientos seleccionado por decisión inteligente del programa o por el usuario. Se lo aplicó a la monitorización en cultivos de P. pastoris.Se desarrolló un sistema de electroforesis capilar (CE) acoplado a un SIA aplicado a la separación de nitrofenoles. Se acopló por primera vez MSFIA con CE para pre-concentración en fase sólida y separación de nitrofenoles. Ambos sistemas mostraban recuperaciones satisfactorias para aguas ambientales. / Five analytical systems using Sequential Injection Analysis (SIA) and Multisyringe Flow Injection Analysis (MSFIA) were developed and applied with satisfactory analytical performance. A SI-analyzer for formaldehyde was developed automating Hantzsch reaction. It was successfully applied to formaldehyde monitoring in continuous medium filtrate of P. pastoris cultivation. A second SI-analyzer was developed for the determination of glycerol and sorbitol. Periodate was used as additional reagent to carry out Malaprade reaction and formaldehyde generated by polyalcohol oxidation was quantified. The system included automated sample dilution and procedures for two working ranges, selected by smart software decision or user-input. It was applied to monitoring of P. pastoris cultivations.A capillary electrophoresis (CE) system was developed and coupled to SIA. It was applied to the determination of nitrophenols. MSFIA and CE were coupled for the first time. Solid phase concentration and separation of nitrophenols were automated. The systems were applied to environmental water samples.

The major contribution of this dissertation is the development of a new integrated measurement and control system for intermixed biogas and photovoltaic systems to achieve safe and optimal energy usage. Literature and field studies show that existing control methods fall short of comprehensive system optimization and fault diagnosis, hence the need to re-look these control methods. The control strategy developed in this dissertation is a considerable enhancement on existing strategies as it incorporates intelligent fuzzy logic algorithms based on C source codes developed on the MPLABX programming environment. Measurements centered on the PIC18F4550 microcontroller were carried out on existing biogas and photovoltaic installations. The designed system was able to accurately predict digester stability, quantify biogas output and carry out biogas fault detection and control. Optimized battery charging and photovoltaic fault detection and control was also successfully implemented. The system optimizes the operation and performance of biogas and photovoltaic energy generation. / Electrical Engineering / M. Tech. (Electrical Engineering)

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-11-16T09:48:38Z No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-11-16T09:49:04Z (GMT) No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-16T09:49:04Z (GMT). No. of bitstreams: 2 Dissertação - Arthur Melo Pereira - 2017.pdf: 8324435 bytes, checksum: a36f9e13810ace212ce9d44a66fc2fb4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-09-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In a society dependent on electric energy for the execution of various daily activities, it is normal that its use is increasingly increasing over time. In order to carry out the transportation of all electric energy, it is essential to use transmission lines, which with increasing energy demand inevitably have tended to multiply throughout the world, and especially in Brazil, given its continental dimensions. Considering the function of the transmission lines for the electrical system, its importance in the context of the electric power supply is remarkable. However, the lines constitute one of the great emitting sources of electric and magnetic fields of low frequency, which has caused concern and has been motivating fact of several studies, like the realized in this work. Therefore, in view of the scenario presented in the previous paragraph, it is necessary to establish ways of calculating the fields more and more precisely. For the calculation of the electric field is used the Image Method, the Maxwell Potential Coefficients Method and the Coulomb Law, and for the magnetic field the Biot-Savart's Law is used. The results obtained for the electric and magnetic fields were for infinite rectilinear geometries, finite rectilinear and for the conductors taking the form of a catenary, the latter geometry being the most real model for the arrangement of the conductors in a line. In all cases treated, an analytical and numerical approach was performed, in order to allow the calculation of the three geometries with accuracy. Taking advantage of the methodology of calculation of the fields, in addition this work proposes a method of support to the monitoring of transmission lines. The method consists of using the Genetic Algorithm associated to the values of the electric and magnetic fields measured to determine the parameters of the line, such as: phase spacing, cable-soil height, equivalent conductor diameter, current and operating voltage. Given the simplicity of implementation when compared to other methods, the achievement of satisfactory results and the need for a single measuring device to monitor the transmission line, the proposed method proves to be viable and promising to carry out the line monitoring process. / Em uma sociedade dependente da energia elétrica para a execução de diversas atividades do cotidiano, é normal que a sua utilização seja cada vez mais crescente no decorrer do tempo. Para realizar o transporte de toda energia elétrica é imprescindível o uso de linhas de transmissão, que com o aumento da demanda de energia inevitavelmente tenderam a se multiplicar pelo mundo e em especial pelo território brasileiro, dadas as suas dimensões continentais. Tendo em vista a função das linhas de transmissão para o sistema elétrico, é notável a sua importância no contexto do fornecimento de energia elétrica. No entanto, as linhas constituem uma das grandes fontes emissoras de campos elétricos e magnéticos de baixa frequência, o que tem causado preocupação e tem sido fato motivador de diversos estudos, como o realizado neste trabalho. Portanto, diante do cenário apresentado no parágrafo anterior, se faz necessário estabelecer formas de calcular os campos de maneira cada vez mais precisa. Para o cálculo do campo elétrico utiliza-se o Método das Imagens, o Método dos Coeficientes de Potencial de Maxwell e a Lei de Coulomb, já para o campo magnético a Lei de Biot-Savart é empregada. Os resultados obtidos para os campos elétricos e magnéticos foram para as geometrias retilíneas infinitas, retilíneas finitas e para os condutores assumindo a forma de uma catenária, sendo que essa última geometria constitui o modelo mais real quanto à disposição dos condutores em uma linha. Em todos os casos tratados foram realizadas uma abordagem analítica e numérica, de maneira a possibilitar o cálculo das três geometrias com exatidão. Aproveitando-se da metodologia de cálculo dos campos, adicionalmente este trabalho propõe um método de apoio ao monitoramento de linhas de transmissão. O método consiste em utilizar o Algoritmo Genético associado aos valores dos campos elétrico e magnético medidos para determinar os parâmetros da linha, como: espaçamento entre fases, altura cabo-solo, diâmetro equivalente dos condutores, corrente e tensão de operação. Dada a simplicidade de implementação quando comparado a outros métodos, a obtenção de resultados satisfatórios e a necessidade de um único aparelho de medição para monitorar a linha de transmissão, o método proposto mostra-se viável e promissor para realizar o processo de monitoramento de linhas.