A novel approach for inspecting the condition of porcelain insulators based on statistical analysis of electromagnetic radiations of live insulators is demonstrated in this thesis. Physical defects such as puncture and contamination can degrade the insulators performance and result in power outages, potentiating costs to utilities. Therefore, condition assessment of line insulators has always been one of the most important aspects of maintenance programs in power networks. Realistic replicas of punctured and contaminated insulators were created in the High Voltage Lab at University of Manitoba, following the IEC standards. These defective insulators were tested under high voltage stress while the electromagnetic radiations originated from the partial discharge activities on the insulators were captured using electromagnetic sensors. During the experimental part of this thesis, a multitude of tests were conducted and resulted in measuring and recording a total of 410,000 cycles of discharge activities. The feature extraction algorithm, developed as part of this thesis, calculates the statistical features of the phase resolved interpretation of partial discharge (PD) pulses. The results of analyzing the extracted features from the radiated signature of defective insulators indicate that the scale and shape parameters of a two sided Weibull distribution function fit to the recorded measurement entail distinct information about the source of discharges that can be used to identify the source of defects. Based on the library of features extracted from the recorded electromagnetic radiations, a support vector machine (SVM) classier, developed as part of this thesis, can successfully classify the radiation signature of punctured and contaminated insulators. Therefore, the main outcome of this research was introducing a novel porcelain insulator inspection technique that can remotely differentiate the defective punctured and contaminated insulators using their electromagnetic radiation signature in a laboratory environment. By utilizing the signature of common discharge activities present in the recorded signature of all tested insulators, a gating algorithm was developed which improved the successful classification rate from 51 % to 75%. The inspection technique proposed in this research can eliminate the safety hazards involved in the live maintenance of line insulators, lower the maintenance costs, and improve the inspection efficiency considering the conventional labour intensive live maintenance assessments. / February 2016

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The implementation of the Caprivi Link Interconnector (CLI) High Voltage Direct Current (HVDC) scheme in 2010 connecting the weak Namibian and Zambian Alternating Current (AC) transmission networks via overhead line is based on Voltage Source Converter (VSC) technology. This world-first combination of attributes presents a unique opportunity to study harmonic interaction between weak AC systems and VSC-based HVDC schemes. Relatively few publications exist that focus on AC and DC harmonic interaction and very few refer to VSC HVDC schemes. Because weak AC systems are much more prone to harmonic distortion than strong AC systems, there is a clear motivation for more detailed work in this field. In order to understand the context wherein AC and DC harmonic interaction exists, the fields of AC power system harmonic analysis and resonance, VSC switching theory, HVDC scheme configurations, Pulse Width Modulation (PWM) techniques and frequency domain analysis techniques are discussed. This thesis then presents the concept of Harmonic Amplitude Transfer Ratio (HATR) by a theoretical analysis of AC and DC harmonic interaction due to the fundamental component, as well as harmonic interaction due to scheme characteristic harmonics and is compared to the simulation results obtained from different software solutions. Simulation and modelling techniques for AC and DC harmonic interaction are discussed including AC and DC systems modelling. The theoretical results and simulation results are compared to the results obtained from a real life case study on the CLI HVDC scheme where a harmonic resonance condition occurred. The correlation of these three sets of results confirms the validity of the theories presented and possible mitigation of the case study resonance problems is explored. The results and conclusion highlight a variety of interesting points on harmonic sequence components analysis, VSC zero sequence elimination, AC and DC harmonic interaction due to the fundamental component and the HATR for different PWM methods, AC and DC harmonic interaction due to scheme characteristic harmonics, modelling techniques and mitigation for the resonance conditions experienced in the analysed real life case study. / AFRIKAANSE OPSOMMING: Die implementering van die Caprivi Skakel Tussenverbinder (CLI) hoogspannings- gelykstroom (HSGS) skema in 2010 wat die swak Namibiese and Zambiese Wisselstroom (WS) transmissienetwerke verbind via „n oorhoofse lyn is gebasseer op Spanningsgevoerde-omsetter tegnologie. Hierdie wêreld-eerste kombinasie van eienskappe verskaf „n unieke geleentheid om harmoniese interaksie tussen swak WS stelsels en Spanningsgevoerde-omsetter Hoogspannings GS stelsels te bestudeer. Relatief min publikasies wat fokus op WS en GS harmoniese interaksie bestaan, en baie min verwys na Spanningsgevoerde-omsetter Hoogspannings GS skemas. Omdat swak WS stelsels baie meer geneig is tot harmoniese verwringing as sterk WS stelsels, is daar „n duidelike motivering vir meer gedetaileerde werk in hierdie veld. Om die konteks te verstaan waarin WS en GS harmoniese interaksie bestaan, word die velde van WS kragstelsel harmoniese analise en resonansie, Spanningsgevoerde-omsetter skakelteorie, Hoogspannings GS skema opstellings, Pulswydte Modulasie (PWM) tegnieke, en frekwensiegebied analiese tegnieke bespreek. Hierdie tesis stel dan die konsep van Harmoniese Amplitude Oordragsverhouding voor deur „n teoretiese analise van WS en GS harmoniese interaksie na aanleiding van die fundamentele komponent, asook harmoniese interaksie a.g.v. harmonieke wat die stelsel kenmerk en word vergelyk met die simulasieresultate verkry uit verskilllende sagteware oplossings. Simulasie- en modelleringstegnieke vir WS en GS harmoniese interaksie word bespreek insluitend WS- en GS stelselmodellering. Die teoretiese resultate en simulasieresultate word vergelyk met die resultate wat verkry is uit „n werklike gevallestudie op die CLI HSGS skema waar „n harmoniese resonansie toestand voorgekom het. Die ooreenkomste tussen hierdie drie stelle resultate bevestig die geldigheid van die teorieë soos uiteengeset voor, en die moontlike verbetering van die gevallestudie resonansie probleme word verken. Die resultate en samevatting beklemtoon „n verskeidenheid punte aangaande harmoniese volgorde-komponent analiese, Spanningsgevoerde-omsetter zero-volgorde uitskakeling, WS en GS harmoniese interaksie na aanleiding van die fundamentele komponent en die Harmoniese Amplitude Oordragsverhouding vir verskillende PWM metodes, WS en GS harmoniese interaksie na aanleiding van skema-kenmerkende harmonieke, modelleringstegnieke, asook verbetering van die resonansie toestande soos ervaar in die analise van die werklike gevallestudie.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Power utilities are expected to keep the cost of electricity as low as possible. They are also expected to be environmentally friendly and, amongst other things, not to produce unacceptable audible noise. When the electric field on a conductor is high enough corona is produced and this is accompanied by audible noise. Air pressure, which is directly related to altitude, has an effect on the voltage at which corona will start. It is more difficult to ionise the air at sea level (high air pressure) than at high altitude (low air pressure). Altitude does not only affect the corona inception voltage, but also the intensity of the audible noise. A thorough scan of literature revealed that there is very little evidence of prior research work on the effect of air density on corona under fair weather (dry) conditions. In South Africa, transmission lines are built at altitudes higher than 1800 m above sea level. The cost of a 400 kV line is in the region of R2M per km. It is important to predict the noise levels under a proposed line accurately, before it is energised. This research indicated that the altitude correction for conductor corona audible noise, under dry conditions, might be steeper than the general accepted correction of 1 dB/300m. This correction, however, appears to be valid for heavy rain conditions. Under heavy rain conditions the corona is mainly determined by the water droplets, whereas under dry conditions the condition of the conductor plays the biggest role. The air density therefore has a bigger effect on the corona performance under dry conditions. The implication of a steeper altitude correction for dry conditions is that too low noise levels will be predicted for a higher altitude, which could lead to complaints. On the other hand, predictions for lower altitudes will be too conservative. / AFRIKAANSE OPSOMMING: Daar word van kragvoorsieners verwag om die koste van elektrisiteit so laag as moontlik te hou. Hulle is verder onder druk om omgewingsvriendelik te wees en om onder andere nie onaanvaarbare hoorbare geraas te veroorsaak nie. Wanneer die elektriese veld op ‘n geleier hoog genoeg is, kan korona ontstaan wat dan hoorbare geraas veroorsaak. Die lugdruk, en daarom die hoogte bo seevlak, beïnvloed die spanning waarby ‘n geleier in korona sal gaan. Dit is moeiliker om die lug te ioniseer by seevlak (hoë lugdruk) as hoog bo seevlak (lae lugdruk). Die hoogte bo seevlak beïnvloed daarom nie net die spanning waarby korona sal begin nie maar ook die intensiteit van die hoorbare geraas. Dit wil voorkom of die effek van hoogte bo seevlak, op hoorbare geraas, a.g.v. geleier korona tot op datum baie skraps nagevors is. Baie min kon in die literatuur gevind word op die effek onder droë toestande. In Suid-Afrika is dit nodig om transmissielyne op hoogtes van 1800 m en hoër te bou. So ‘n lyn (400 kV) kos in die omgewing van R2M per km. Dit is daarom van uiterste belang om die geraasvlakke wat ‘n beplande lyn sal veroorsaak, akkuraat te bepaal, voordat so ‘n lyn aangeskakel word. Hierdie navorsing het gewys dat die effek van hoogte bo seespieël op hoorbare korona geraas onder droë toestande groter kan wees as wat algemene aanvaar word. Die helling van die korreksiefaktor vir hoogte bo seevlak blyk steiler as 1 dB/300 m te wees vir droë toestande. Die implikasie hiervan is dat geraas voorspellings vir hoër hoogtes bo seespieël te laag sal wees en die vir lae hoogtes te konserwatief kan wees. Die navorsing stem egter saam met die korreksiefaktor van 1 dB/300 m onder swaar reën toestande. Dit wil voorkom of die invloed van die waterdruppels op geleier korona groter is as lugdruk. Onder droë toestande speel die toestand van die geleier 'n groter rol en is die effek van lugdruk groter.

A l’heure où la miniaturisation des technologies CMOS sur substrat massif atteint des limites, la technologie FDSOI (silicium sur isolant totalement déserté) s’impose comme une alternative pour l’industrie en raison de ses meilleures performances. Dans cette technologie, l’utilisation d’un substrat SOI ultramince améliore le comportement des transistors MOSFETs et garantit leur intégrité électrostatique pour des dimensions en deçà de 28nm. Afin de lui intégrer de nouvelles fonctionnalités, il devient nécessaire de développer des applications dites « haute tension » comme les convertisseurs DC/DC, les régulateurs de tension ou encore les amplificateurs de puissance. Cependant les composants standards de la technologie CMOS ne sont pas capables de fonctionner sous les hautes tensions requises. Pour répondre à cette limitation, ces travaux portent sur le développement et l’étude de transistors MOS haute tension en technologie FDSOI. Plusieurs solutions sont étudiées à l’aide de simulations numériques et de caractérisations électriques : l’hybridation du substrat (gravure localisée de l’oxyde enterré) et la transposition sur le film mince. Une architecture innovante sur SOI, le Dual Gound Plane EDMOS, est alors proposée, caractérisée et modélisée. Cette architecture repose sur la polarisation d’une seconde grille arrière pour offrir un compromis RON.S/BV prometteur pour les applications visées. / Nowadays the scaling of bulk silicon CMOS technologies is reaching physical limits. In this context, the FDSOI technology (fully depleted silicon-on-insulator) becomes an alternative for the industry because of its superior performances. The use of an ultra-thin SOI substrate provides an improvement of the MOSFETs behaviour and guarantees their electrostatic integrity for devices of 28nm and below. The development of high-voltage applications such DC/DC converters, voltage regulators and power amplifiers become necessary to integrate new functionalities in the technology. However, the standard devices are not designed to handle such high voltages. To overcome this limitation, this work is focused on the design of a high voltage MOSFET in FDSOI. Through simulations and electrical characterizations, we are exploring several solutions such as the hybridization of the SOI substrate (local opening of the buried oxide) or the implementation in the silicon film. An innovative architecture on SOI, the Dual Ground Plane EDMOS, is proposed, characterized and modelled. It relies on the biasing of a dedicated ground plane introduced below the device to offer promising RON.S/BV trade-off for the targeted applications.

abstract: Infant mortality rate of field deployed photovoltaic (PV) modules may be expected to be higher than that estimated by standard qualification tests. The reason for increased failure rates may be attributed to the high system voltages. High voltages (HV) in grid connected modules induce additional stress factors that cause new degradation mechanisms. These new degradation mechanisms are not recognized by qualification stress tests. To study and model the effect of high system voltages, recently, potential induced degradation (PID) test method has been introduced. Using PID studies, it has been reported that high voltage failure rates are essentially due to increased leakage currents from active semiconducting layer to the grounded module frame, through encapsulant and/or glass. This project involved designing and commissioning of a new PID test bed at Photovoltaic Reliability Laboratory (PRL) of Arizona State University (ASU) to study the mechanisms of HV induced degradation. In this study, PID stress tests have been performed on accelerated stress modules, in addition to fresh modules of crystalline silicon technology. Accelerated stressing includes thermal cycling (TC200 cycles) and damp heat (1000 hours) tests as per IEC 61215. Failure rates in field deployed modules that are exposed to long term weather conditions are better simulated by conducting HV tests on prior accelerated stress tested modules. The PID testing was performed in 3 phases on a set of 5 mono crystalline silicon modules. In Phase-I of PID test, a positive bias of +600 V was applied, between shorted leads and frame of each module, on 3 modules with conducting carbon coating on glass superstrate. The 3 module set was comprised of: 1 fresh control, TC200 and DH1000. The PID test was conducted in an environmental chamber by stressing the modules at 85°C, for 35 hours with an intermittent evaluation for Arrhenius effects. In the Phase-II, a negative bias of -600 V was applied on a set of 3 modules in the chamber as defined above. The 3 module set in phase-II was comprised of: control module from phase-I, TC200 and DH1000. In the Phase-III, the same set of 3 modules which were used in the phase-II again subjected to +600 V bias to observe the recovery of lost power during the Phase-II. Electrical performance, infrared (IR) and electroluminescence (EL) were done prior and post PID testing. It was observed that high voltage positive bias in the first phase resulted in little/no power loss, high voltage negative bias in the second phase caused significant power loss and the high voltage positive bias in the third phase resulted in major recovery of lost power. / Dissertation/Thesis / M.S. Engineering 2011

abstract: This research presents potential and electric field calculations on medium voltage (MV) epoxy insulated outdoor current transformers (CTs) using a numeri-cal calculation approach. Two designs of MV dry-type epoxy insulated CTs were modeled using 3D field simulation software COULOMB® 9.0. Potential and elec-tric fields were calculated based on boundary element method. Different condi-tions such as dry exterior surface, wet exterior surface and internal voids were considered. The research demonstrates that the presence of internal conductors in CTs results in a less severe surface electric field distribution when compared to outdoor insulators of the same voltage range and type. The high electric field near the exited end triple-point of the CT reduces. This remained true even under wet conditions establishing better outdoor performance of CTs than outdoor insulators which have no internal conductors. The effect of internal conductors on voids within the insulation structure was also established. As a down side, internal voids in CTs experience higher electric field stress than in conductor-less insulators. The work recognizes that internal conducting parts in dry type CTs improves their outdoor performance when compared to electrical equipment without internal conductors. / Dissertation/Thesis / M.S. Electrical Engineering 2012

Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

abstract: Transmission voltages worldwide are increasing to accommodate higher power transfer from power generators to load centers. Insulator dimensions cannot increase linearly with the voltage, as supporting structures become too tall and heavy. Therefore, it is necessary to optimize the insulator design considering all operating conditions including dry, wet and contaminated. In order to design insulators suitably, a better understanding of the insulator flashover is required, as it is a serious issue regarding the safe operation of power systems. However, it is not always feasible to conduct field and laboratory studies due to limited time and money. The desire to accurately predict the performance of insulator flashovers requires mathematical models. Dynamic models are more appropriate than static models in terms of the instantaneous variation of arc parameters. In this dissertation, a dynamic model including conditions for arc dynamics, arc re-ignition and arc motion with AC supply is first developed. For an AC power source, it is important to consider the equivalent shunt capacitance in addition to the short circuit current when evaluating pollution test results. By including the power source in dynamic models, the effects of source parameters on the leakage current waveform, the voltage drop and the flashover voltage were systematically investigated. It has been observed that for the same insulator under the same pollution level, there is a large difference among these flashover performances in high voltage laboratories and real power systems. Source strength is believed to be responsible for this discrepancy. Investigations of test source strength were conducted in this work in order to study its impact on different types of insulators with a variety of geometries. Traditional deterministic models which have been developed so far can only predict whether an insulator would flashover or withstand. In practice, insulator flashover is a statistical process, given that both pollution severity and flashover voltage are probabilistic variables. A probability approach to predict the insulator flashover likelihood is presented based on the newly developed dynamic model. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2016

[pt] Os equipamentos elétricos de alta tensão são peças fundamentais na produção industrial. Porém, os sistemas de isolamento são os que mais apresentam problemas ao longo da vida útil dos nossos equipamentos. Suas propriedades dielétricas são alteradas ao longo do tempo e, desta forma devem ser monitoradas. Dentre as principais anomalias acometidas aos sistemas de isolamento, estão as Descargas Parciais (DP).Elas são resultado do rompimento da rigidez dieétrica do material isolante submetido a um intensivo campo elétrico . Até alguns anos atrás, em virtude da existência dos mecanismos de medição que possibilitassem o armazernamento de dados, muito pouco se efetuava para o acompanhamento das condições apresentadas pelos sistemas de isolamento.Com advento de sistemas digitais,esta limitação foi vencida. No entanto, a obtenção de dados reais e sua posterior avaliação são mecanismos que ainda carecem de um bom número de anos de experiência para sua elucidação. Esse fato advém,principalmente, da dificuldade em obtê-los .Como forma de contornar problema de falta de dados reais, foram desenvolvidas as célualas que têm como características simular os principais tipos de defeitos existentesnos sistemas de isolamento de alta tensão.Essas células são isoladas por materiais dielétricos idênticos ao que são usados em equipamentos elétricos reais. Dessa forma, foi possível a simulação de defeitos e a posterior aquisição, através do método eletromagnético de medição de DP, de um número suficiente de dados. Esses dados foram,então, aplicados no ajuste do sistema de reconhecimento de padrões de DP, onde se faz uso da teoria fractal, como um mecanismo de compactação de dados, por meio das grandezas fractais denominadas de dimensão fractal e lacunaridade, e também das redes neurais artificiais, com a utilização de um algoritmo supervisionado através do modo de treinamento back-propagation.Essa etapa,denominada de laboratorial, foi de fundamental importância para obtenção de conhecimento experimental bastante útil para a aplicação em ambientes reais.Outra fonte de informação também foi disponibilizada e se refere aos níveis de gases encontrados nas amostras de óleo colhidas junto aos transformadores de potência. Esta análise, conhecida como análise cromatográfica,baseia-se na existência de determinados tipos de gases para apontar o tipo de anomalia acometida ao sistema de isolamento do equipamento elétrico.Embora existam alguns métodos capazes de realizar tal diagnóstico, a tese fez uso das informações de um especialista.Essas afirmações foram então empregadas em um sistema neuro-fuzzy hierárquico, que tem como fundamento a extração de regras que relacionam os níveis de gases obtidos pela cromatografia gasosa com o tipo de anomalia existente no sistema de isolamento .Após esse processo um conjunto de transformadores de potência reais foi monitorado através de técnicas de cromatografia e do método eletromagnético.As duas técnicas, portanto, são usadas para estimar a ocorrência de DP nos sistemas de isolamento e, cosequentemente, o nível de degradação dos mesmos.Desta forma, a tese apresenta um sistema de diagnóstico que se utilizada de dados internos ao sistema de isolamento dos equipamentos elétricos baseados na ocorrência de DP. Esse sistema indica, ao seu final, um conceito sobre o atual estado operativo do mesmo, podendo este ser utilizado em um planejamento mais adequado que previna perdas intempestivas. A avaliação de desempenho do modelo, tanto laboratorial quanto em campo, apresentou ídices elevados, culminando em uma confirmação visual interna de um equipamento real, que comprova a eficiência e a importãncia do sistema. / [en] High voltage (HV) power apparatus are fundamental parts in the industrial process. It is also well Known that electrical insulation systems are the parts that present more problems through the life cycle of an HV apparatus. The dielectric properties of materials are altered during operation time and for this reason they should be monitored. Among the main anomalies that can affect the insulation systems are the Partial Discharges (PD). They are result of a partial failure of the dielectric rigidity of the insulating material submitted to an intense electric field.Until recently, probably due to the inexistence of measurement mechanisms that made possible the storage of data, very a little could be done to accompany the actual condition of insulation systems. With the coming of digital systems, this limitation was overcome.However, the obtention of real data and their subsequent evaluation are mechanisms that still will demand a good number of years of experience to perfect . This fact occurs, mainly, due to the difficulty in obtaining those data .As a way to the problem of lack of real data, special cells development with the purpose of simulating the principal types of defects that occur in HV insulation equipment . In that way, it was possible to do both the simulation of the defects and the measurement and acquisition, through the electromagnetic measurement method, of an expressive number of data. Those data were used to adjust a system of pattern recognition of PD, using artificial neural networks, where it is also made use of the fractal theory, as a mechanism of data compression, by measures of fractal dimension and lacunarity. That stage, denomited laboratory, was of fundamental importance to the obtention of experimental . Knowledge very useful to the development of real operating systems .Another source of information that was also available refers to the levels of gases found in oil samples from the interior of power transformers. This analysis, known as analysis of dissolved gases or chromatography, is based on the existence of certain types of gases as an indication of the type of anomaly on the electrical insulation system. Although some mehods exist, capable of accomplishing such diagnosis, the thesis made use of a specialist`s information. Those statements were used then in a hierarchical neuro-fuzzy model, designed method, with the type of anomaly existent in the insulation system. After that process, a real sample of operating HV power apparatus was monitored using the two analysis techniques, the chromatography and the electromagnetic method of PD measurement.Therefore these two techniques, are used to estimate the PD activity in the insulation systems and, consequently, their level of degradation . In resume the thesis presents a diagnosis system that makes use of internal data from the electrical insulation system with base in the PD occurrence. That system indicates, at the end, a concept of its current operative state, being able to be used in a more appropriate planning in order to prevent inopportune losses. The evaluation of the model, as much of simulating as in field, present high indexes and a visual confirmation intern of a real equipment, that proves the efficiency and the importance of system.

O presente trabalho teve como objetivo estudar diferentes tecnologias na extração de óleo da semente de gergelim e de compostos fenólicos e proteínas da torta de gergelim. Este estudo está dividido em quatro partes. O objetivo da primeira parte do trabalho foi extrair compostos fenólicos de diferentes tortas de nozes e sementes nas mesmas condições e comparar o teor de tais compostos e a atividade antioxidante dos extratos. Nessa fase, foram utilizadas nos experimentos tortas das sementes de girassol, linhaça e gergelim, e das nozes amêndoa, pecã, macadâmia e avelã. O extrato da torta de noz pecã apresentou o maior teor de todos os compostos fenólicos analisados, seguido pelo extrato da torta de semente de girassol e de avelã. Essas amostras também apresentaram as maiores atividades antioxidantes. As etapas seguintes do trabalho focaram-se no gergelim. A segunda parte do trabalho teve como objetivo a otimização da extração, pela metodologia convencional, de fenólicos totais e lignanas da torta de gergelim. Inicialmente, um modelo polinomial de segunda ordem foi utilizado para predição dos resultados, mediante a variação da temperatura, concentração de etanol e razão, sólido/solvente. As variáveis de resposta foram as concentrações de fenólicos totais, de sesamina e de sesaminol triglicosídeo e a atividade antioxidante dos extratos obtidos. Entre os compostos analisados, o sesaminol triglicosídeo está presente em maior quantidade na torta de gergelim. A razão sólido/solvente e a concentração de etanol foram os fatores que mais afetaram a extração, enquanto a temperatura demonstrou uma influência reduzida. Na terceira etapa, o escopo da pesquisa foi a avaliação de metodologias alternativas na extração desses mesmos compostos e, também, de proteínas. As tecnologias usadas foram as de campo elétrico pulsado (CEP) e de descargas elétricas de alta tensão (DEAT). A análise da aplicação de CEP e de DEAT foi realizada usando essas tecnologias como pré-tratamentos ao processo de extração com solvente. Os resultados demonstraram que as técnicas foram eficazes e aumentaram os rendimentos do processo para fenólicos totais, lignanas e proteínas da torta. O uso de diferentes porcentagens de etanol também se mostrou significativo nessa etapa, entretanto, esse efeito foi reduzido quando utilizadas as tecnologias elétricas. Da mesma forma, o efeito da temperatura na etapa difusiva foi menor quando os pré-tratamento foram utilizados. Os comportamentos observados sugerem que a aplicação de CEP e DEAT aumenta a eficiência da extração de compostos de interesse. Por fim, na quarta parte do trabalho, objetivou-se melhorar a eficiência do processo de extração do óleo de gergelim aplicando as tecnologias previamente citadas. Esses experimentos demonstraram um efeito significativo dos tratamentos de CEP e DEAT e um aumento na quantidade de óleo extraído com o aumento da energia aplicada às sementes. O uso de DEAT gerou um aumento maior na quantidade de óleo extraído, se comparado à tecnologia de CEP. / The goal of the present work was to study different technologies in the extraction of oil from sesame seed and phenolic compounds and proteins from sesame cake. This study is divided in four parts. The first part aimed to extract water-soluble compounds from different seed and nut cakes under the same conditions and compare the phenolic content and antioxidant activity of the extracts. For the first portion of the study, seed cakes of sunflower, pumpkin, flaxseed and defatted sesame, and nut cakes of almond, pecan, macadamia and hazelnut were used in the experiments. The extract from pecan nut cake presented the highest amounts of all compounds analyzed, followed by sunflower seed and hazelnut cake extracts. These samples also had the highest antioxidant activities. The following steps of the work focused on sesame only. The second part of the work aimed to optimize the extraction of total phenolics and lignans from sesame seed cake. Initially, a second-order polynomial model was set up to predict the responses in different temperatures, solid/solvent ratios and ethanol concentrations. The response variables were the concentrations of total phenolics, sesamin, sesaminol triglucoside and antioxidant activity of the extracts. Among the analyzed compounds, ST is presented in the highest quantity in sesame cake. Solid to liquid ratio and ethanol concentration where the most important factors affecting extraction, whereas temperature showed reduced influence. In the third part of this work, the aim was to evaluate alternative methodologies in the extraction of phenolics and proteins. The technologies used were pulsed electric fields (PEF) and high voltage electric discharges (HVED). These methods were used as pre-treatments, prior to diffusion. Result show that PEF and HVED were efficient and increased the extraction yield for phenolic compounds, lignans and proteins from the cake. The use of different percentages of ethanol was also significant in this stage; however, the effect of this parameter was reduced when the electrical treatments were used. In the same way, temperature also showed a smaller influence on the results when the pre-treatments were used. The observed behaviors suggest that the use of PEF and HVED increases extraction efficiency. Finally, the goal of the last part of the work was to improve oil expression from sesame seeds, using the aforementioned technologies. These experiments show a significant effect of both PEF and HVED. It was observed an increase of the amount of oil extracted with the energy input applied to the seeds. When compared both technologies, HVED showed a more expressive effect then PEF.