Solar-blind Ultraviolet cameras are used to detect missile plumes and perform the detection of corona on high voltage electrical lines. This study investigates the influence of the spectral transfer function of a specific solar-blind Ultraviolet camera upon Ultraviolet energy measurement results. In addition to the spectral transfer response investigated, is the influence of other related factors, including the specific camera operation and design. The possibility that the particular camera‟s measurements are being influenced by its own spectral transfer function, is initially investigated by using a simplified model. The objective of the model was to determine if the hypothesis is possible. In addition to the spectral transfer function of the camera, other factors that could influence camera measurements were also investigated in the literature. Included are highlights from other research conducted utilising this type of camera for high voltage electrical purposes, as well as comments for further research. Subsequently experiments were executed to characterise the camera, including the determination of the spectral transfer function of the specific camera, taking into considering limitations of the camera and related equipment. Derived from the spectral transfer of the camera and the other experiments and literature, a proposed method of calibration is presented, as well as suggestions for the improvement of the camera and better utilisation thereof. / Son-blind ultraviolet kameras word gebruik om missiel uitlaat gasse sowel as korona op hoogspannings kraglyne op te spoor. Die studie ondersoek die invloed van die spektrale oordragfunksie van „n spesifieke son-blind ultraviolet kamera op ultraviolet energie meetingsresultate. Addisioneel tot die spektrale response geondersoek, is die invloed van ander verwante faktore op metings insluitend die spesifieke kamera se werking en ontwerp. Die moontlikheid dat die spesifieke kamera se metings beïnvloed word deur sy eie spektrale oordragfunksie, word aanvanklik eers ondersoek aan die hand van ‟n eenvoudige model. Die doel van die model is om te bepaal of die hipotese moontlik is. Addisioneel tot die spektrale oordragfunksie van die kamera, word ander faktore wat die kamerametings kon beïnvloed het, ook ondersoek in die literatuur. Ingesluit is hoogtepunte van ander navorsing wat die tipes kameras gebruik vir hoogspannings elektriese doeleindes, plus kommentaar vir verdere navorsing. Vervolgens is eksperimente uitgevoer om die kamera te karakteriseer, insluitend die bepaling van die spesifieke kamera se spektrale oordragfunksie, met inagneming van die beperkings van kamera en verwante toerusting. Afgelei uit die spektrale oordragfunksie van die kamera en die ander eksperimente en literatuurstudie, is „n voorgestelde kalibrasiemetode aangebied, asook voorstelle vir die verbetering en die kamera en meer effektiewe gebruik daarvan. / Dissertation (MEng (Electronic Engineering))--University of Pretoria, 2015. / Electrical, Electronic and Computer Engineering / MEng (Electronic Engineering) / Unrestricted

El diseño de cimentaciones para torres de alta tensión en el Perú actualmente no tiene una regulación o normativa específica que indique las distintas consideraciones técnicas a tener en cuenta en el diseño (en nuestro país basadas en el Código Nacional de Electricidad y la NORMA E.030), por lo que usualmente este es realizado usando métodos convencionales poco óptimos. La primera parte de esta investigación realiza el estudio geotécnico para un punto de referencia específico en la formación “La Herradura” del distrito de Chorrillos, Lima, Perú. De este estudio se obtienen las características y parámetros del lugar como la Resistencia a la Compresión Simple de las Rocas, Peso Específico de la roca y estado en el que se encuentra el macizo rocoso a través de métodos prácticos que permiten estudiar cualquier tipo de terreno. La segunda parte se enfoca en el diseño geotécnico de una cimentación para torres de alta tensión usando pernos de anclaje, para lo que se toma en cuenta la Especificación CFE JA100-64 (México), la IEEE (Guide for Transmission Structure Foundation Design and Testing) y Reglamento Nacional de Edificaciones (Perú). La tercera parte desarrolla un análisis paramétrico (proceso que evalúa la variabilidad de ciertos parámetros con respecto a valores “naturalmente” constantes definidos a través de diversos análisis de laboratorio e investigaciones científicas obtenidas de fuentes bibliográficas) en función del procedimiento que se ha establecido para el diseño de cimentaciones de torres de alta tensión usando pernos de anclaje. La finalidad de este análisis es determinar correlaciones que puedan ser significativas o no, a la par de identificar tendencias de comportamientos de acuerdo con la variabilidad de parámetros especificados previo a cada proceso iterativo y así poder proponer un método de diseño optimizado. La cuarta parte de la investigación desarrolla la propuesta de una metodología de diseño teniendo en cuenta el diseño geotécnico que se realizó y el análisis paramétrico con el fin de optimizar el diseño, cuantificando las ventajas y desventajas de asumir valores mayores o menores a los expuestos en la parte del diseño geotécnico. A la vez, se describe el aporte de la técnica y algunos motivos por los cuales sería conveniente usarla. Finalmente, se desarrollan las distintas conclusiones que generaron los cálculos y pruebas realizadas, de acuerdo con el alcance y objetivos del tema de investigación y se brindan recomendaciones que futuros investigadores deberían tomar en cuenta cuando se busque ampliar el estudio de la técnica y así establecer una normativa más orientada a las condiciones naturales y/o típicas de nuestro país. / The design of foundations for high voltage towers in Peru does not currently have a specific regulation or regulation that indicates the different technical considerations to take into account in the design, so this is usually done using unconventional conventional methods. The first part of this investigation carries out the geotechnical study for a specific reference point in the “La Herradura” formation of the Chorrillos district, Lima, Peru. From this study the characteristics and parameters of the place are obtained such as the Resistance to the Simple Compression of the Rocks, Specific Weight of the rock and state in which the rock mass is located. The second part focuses on the geotechnical design of a foundation for high voltage towers using anchor bolts, for which the Especificación CFE JA100-64 (Mexico), the IEEE (Guide for Transmission Structure Foundation Design and Testing) and Reglamento Nacional de Edificaciones (Peru) ) are taken into account. The third part develops a parametric analysis based on the procedure that has been established for the design of foundations of high-voltage towers using anchor bolts. The purpose of this analysis is to determine correlations that may be significant or not, while identifying behavioral trends according to the variability of parameters specified prior to each iterative process. This part provides practical expressions that can be used to have a previous design perspective and choose to make certain improvements. The fourth part of the research develops the proposal of a design methodology taking into account the geotechnical design that was carried out and the parametric analysis in order to optimize the design, quantifying the advantages and disadvantages of assuming values greater or less than those exposed in the part of geotechnical design. Finally, the different conclusions that generated the calculations and tests performed are developed, according to the scope and objectives of the research topic and recommendations that future researchers should take into account when seeking to expand the study of the technique. / Tesis

La lutte contre la pollution atmosphérique est un enjeu majeur de ce XXIème siècle. Le centre deMarcoule du CEA développe différents procédés de traitement de déchets issus du nucléaire parincinération/vitrification qui génèrent des gaz de combustion nécessitant un traitement. Pour cefaire, le CEA utilise la précipitation électrostatique, technique de traitement d’effluents gazeuxemployée pour la filtration des particules fines.Cette thèse est consacrée à l’optimisation des performances d’un électrofiltre alimenté parhautes puissances pulsées. L’un des objectifs est de dimensionner et réaliser une nouvelle électrodeémissive adaptée au développement d’un nouveau procédé d’incinération. Cette nouvelle électrodecouplée à son alimentation HT, dont les paramètres électriques ont été optimisés, ont permisd’obtenir des rendements de filtration maximum durant des temps de fonctionnement enadéquation avec des applications industrielles. L’impact des caractéristiques physico-chimiques despoussières sur l’efficacité de filtration a été analysé.Une étude spécifique a également porté sur l’évolution des différents régimes de décharge quise développent dans l’électrofiltre de manière à identifier les phénomènes responsables de la chuted’efficacité du procédé. Les bénéfices de l’électrode émissive et d’un générateur hybride, combinantdes impulsions de tension superposées à un fond continu, ont clairement été mis en évidence parleurs effets sur l’initiation des "back corona" et par conséquent sur la durée de fonctionnement àrendement optimal. / The fight against air pollution is a major issue in the twenty-first century. The center of Marcouleof CEA develops different waste treatment processes by incineration / vitrification that generatecombustion gases requiring treatment. To do this, the CEA uses the electrostatic precipitation, atechnical waste gas treatment employed for thin particles filtration.This thesis is dedicated to optimizing the performance of an electrofilter supplied by high pulsedpowered. One of the goals is to size and achieve a new emissive electrode adapted to thedevelopment of a new incineration process. This new electrode coupled to its High Voltage (HV)power supply, which electrical parameters were optimized, allowed to obtain maximum filtrationefficiency during operating times in line with industrial applications. The impact of thephysicochemical characteristics of dusts on the filtration efficiency was analyzed.A specific study also focused on the evolution of different discharge conditions that develop inthe electrofilter to identify the phenomena responsible for the process efficiency fall. The intake ofthe emissive electrode and a hybrid generator, combining a continuous background voltagesuperimposed with impulses, has clearly been demonstrated by their effects on back coronainitiation and therefore on the optimal efficiency operation duration.

<p>  </p> <p>Plastics are the most common polymers used in various industries. However, million tons of plastics are produced and disposed every year around the world, and part of them end up entering the environment and agricultural ecosystems in the form of microplastics. Microplastics have become an environmental and health threat to aquatic species and humans because they are small and can easily reach water bodies for municipal and agricultural uses. Microplastics have been traced in food commodities and products derived from animals and even found in bottles of drinking water. As an approach to permanently remediating microplastics, current microplastic degradation techniques, however, require high energy inputs and thus are generally not cost-efficient. High-voltage atmospheric cold plasma (HVACP) is a low-cost energy-efficient technology to produce highly reactive species that can induce physicochemical changes in polymers. This study, for the first time, used HVACP as a novel remediation strategy for microplastics. HVACP was generated by dielectric barrier discharge at 50 kV using oxygen, nitrogen, or their mixture as working gas. Two types of microplastics, polypropylene (PP) and low-density polyethylene (LDPE), were treated for 30 min, and the effect of 24-h post-treatment was also studied. The properties of HVACP-treated microplastics, including weight, particle size, crystallinity, melting point, carbonyl index (CI), and surface morphology, were comprehensively analyzed. HVACP treatments were found effective in degrading both PP and LDPE microplastics. A larger extent of degradation was observed with PP microplastics treated by O/N mixture plasma, but the nitrogen plasma-treated sample showed a higher degree of oxidation according to its CI. For PE microplastics, oxygen plasma caused more degradation, but post-treatment did not promote further oxidation. The results indicated two potential mechanisms for microplastic degradation by HVACP. LDPE microplastics were degraded by oxidative reactions caused by highly reactive oxygen species, and PP microplastics followed a hydrolytic pathway of degradation as they became more hydrophilic after HVACP treatment. This study proved that HVACP is a promising method for microplastic degradation, and thus has great potential for addressing the severe challenges of microplastics that the food and agriculture sectors are currently facing.</p>

[pt] Existe uma perspectiva crescente da utilização de alta tensão em corrente contínua (ATCC). Assim, com base em informações da literatura sobre ensaios elétricos em equipamentos para ATCC e em exigências quanto à confiabilidade de procedimentos metrológicos, nesta dissertação, propõe-se o monitoramento e análise de um parâmetro (ripple) de forma que se possa garantir a rastreabilidade de sistemas de medição de referência (SMR). Os SMRs permitem apenas uma análise quantitativa da tensão de calibração, sendo preciso avaliar e garantir que a incerteza não seja influenciada por ripples de até 3 por cento, mas torna-se necessário também fazer uma avaliação qualitativa. No caso de ensaios em ATCC, o uso de diferentes fontes e retificadores provoca ripple em diferentes níveis, influenciando na qualidade da tensão fornecida e possivelmente em outros parâmetros relevantes descritos na norma ABNT NBR IEC 60060-1:2013. Nesse contexto, o objetivo desta dissertação foi o aperfeiçoamento e validação, com o rascunho da norma IEC 61083-4, de um algoritmo de medição previamente desenvolvido em LabVIEW que se comunique com um multímetro de 8 (1 sobre 2) dígitos e estime todos os parâmetros normalizados. Estabeleceu-se, ainda, os procedimentos necessários para calibração em ATCC e a análise da influência do ripple a partir dos parâmetros definidos pela norma. Para validar a metodologia proposta nesta dissertação foram feitos ensaios com diferentes arranjos, cuja finalidade foi comparar, estatisticamente, as incertezas de medição da calibração com diferentes níveis de ripple no SMR. Finalmente, os resultados obtidos indicam que o ripple não influencia na calibração. / [en] There is a growing prospect of using high voltage in direct current (HVDC). Thus, based on information from the literature on dielectric tests in equipment for HVDC and requirements regarding the reliability of metrological procedures, this dissertation aims at monitoring and analyzing a specific parameter (ripple) in a way that can guarantee the traceability of reference systems. The reference systems allow only a quantitative analysis of the calibration voltage, being necessary to evaluate and ensure that the measurement uncertainty is not influenced by ripples of up to 3 percent, but it is also necessary to make a qualitative assessment. In the case of HVDC tests, the use of different power supplies and rectifiers causes ripple at different levels, influencing the quality of the supplied voltage and possibly other relevant parameters for the ABNT NBR IEC 60060-1:2013 standard. In this context, the objective of this dissertation was the improvement and validation, with the draft of the IEC 61083-4 standard, of a signal acquisition and processing algorithm developed in LabVIEW that communicates with an 8 (1 over 2) digit multimeter and estimates all the normalized parameters. It is also intended to establish the procedures introduced for HVDC calibration and an analysis of the ripple influence from the parameters defined by the standard. To validate the methodology proposed in this dissertation, tests were made with different arrangements, with universal and purely resistive dividers, and different ripple levels, in the laboratory, statistically comparing the calibration measurement uncertainties with different ripple levels in the traceability of reference systems. Finally, the results indicate that the ripple does not influence the calibration.

No description available.

It is anticipated that massive amounts of energy will be transferred long distances via High-Voltage Direct Current (HVDC) links in the future and the prospect of having meshed HVDC grids is envisioned, for example the European super grid. Such a power system would benefit greatly if HVDC circuit breakers could reliably clear faults within the HVDC network. Different ways to break large direct currents have been proposed throughout the years and one distinguished concept is based on generating an artificial zero-crossing of the current and pass it through a mechanical interrupter as it opens. This concept is implemented in the Voltage-Source Converter Assisted Resonant Current (VARC) circuit breakers developed at Scibreak which require auxiliary power from an off-line supply unit to energize their electronic equipment. This thesis continuous and builds on research previously carried out at Scibreak on a special Auxiliary Power Supply (APS) concept for 525 kV HVDC applications. In essence, it is a unique modularized high-frequency transformer whose power transfer and voltage withstand capabilities are the cornerstones of its design. The APS must supply an adequate amount of power to drive the VARC circuit breakers with preferably high efficiency while also fulfilling the considerable insulation demands of HVDC grids. A feasibility study of this APS concept was carried out by building a parametric 3D model in the Finite Element Analysis (FEA) software Ansys Maxwell which includes all parts that affect both its magnetic and electrical properties. The initial model reproduced experimental results from a magnetic APS prototype and was then used to explore a plethora of different geometries and materials with regards to its magnetic and dielectric designs. Specific design candidates were selected for more in-depth analysis and experimental work. All obtained results together with knowledge of commercially available materials show that the APS holds great promise to meet the necessary design criteria for its HVDC applications. Its dielectric design is well suited to continuously handle an operating voltage of 525 kV DC, meet the required impulse voltage levels of the grid and properly shield the magnetic structure. It is expected to have a long life time where the design criterion was always 30 years in this work. Moreover, its magnetic design is anticipated to supply a few kW of active power with efficiencies between 80 to 95 percent and manage a continuous operating time of 5 min. Both design aspects are interchangeable to a decent extent in order to cope with one another and produce a compromised design. / Det förväntas att enorma mängder energi kommer överföras långa sträckor med Högspänd Likström (HVDC) i framtiden och blivande HVDC-nät håller på att föreställas, till exempel det europeiska superelnätet. Ett sådant kraftsystem skulle ha stor nytta av HVDC-brytare som tillförlitligt kan bryta felströmmar inom HVDC-nätet. Olika sätt att bryta stora likströmmar har föreslagits med åren och ett distinkt koncept bygger på att generera en artificiell nollgenomgång av strömmen och föra den genom en mekanisk brytarkammare när den öppnas. Detta koncept är implementerat i de så kallade VARC-strömbrytarna som utvecklas hos Scibreak, vilka kräver hjälpmatning av effekt från en extern försörjningsenhet för att driva deras elektroniska utrustning. Denna avhandling fortsätter och bygger vidare på forskning som tidigare utförts hos Scibreak på ett speciellt Hjälpmatningskoncept (APS) för 525 kV HVDC-tillämpningar. I huvudsak är det en unik modulariserad högfrekvenstransformator vars kraftöverföring och spänningståligheter är huvudfokusen i dess design. Hjälpmatningen måste kunna leverera en tillräcklig mängd effekt för att driva VARC-brytarna med företrädesvis hög verkningsgrad, samtidigt som den ska uppfylla de betydande isolationskraven för HVDC-nät. En genomförbarhetsstudie av detta APS-koncept gjordes genom att bygga en parametrisk 3D modell i Finita Elementmetodsprogramvaran (FEM) Ansys Maxwell som inkluderar alla delar som påverkar både dess magnetiska och elektriska egenskaper. Den initiala modellen reproducerade experimentella resultat från en magnetisk APS-prototyp och användes sedan för att utforska en uppsjö av olika geometrier och material med avseende på dess magnetiska och dielektriska konstruktioner. Specifika designkandidater valdes ut för mer djupgående analys och experimentiellt arbete. Alla erhållna resultat tillsammans med kunskap om kommersiellt tillgängliga material visar att APS:n har stora möjligheter att uppfylla alla nödvändiga kriterier för sina HVDC-tillämpningar. Dess dielektriska design är väl lämpad för att kontinuerligt hantera en driftspänning på 525 kV DC, möta de erforderliga stötspänningståligheterna i nätet och ordentligt skydda den magnetiska strukturen. Den förväntas ha en lång livstid där designkriteriet alltid var 30 år i detta arbete. Dessutom förväntas dess magnetiska design leverera några kW aktiv effekt med verkningsgrader mellan 80 till 95 procent och klara en kontinuerlig drifttid på 5 min. Båda designaspekterna kan justeras i en någorlunda utsträckning för möta de krav som ställs från varandra och producera en kompromissad design.

Das kompakte Design von gasisolierten Systemen und die Unabhängigkeit gegenüber Umgebungsbedingungen führt zu einer idealen Eignung des Betriebsmittels für den Einsatz in modernen Energieversorgungssystemen. Ein Betrieb der Anlagen unter Gleichspannungsbelastung ist dabei aufgrund der zunehmenden räumlichen Distanz zwischen Erzeugungs- und Verbrauchszentren unumgänglich. Der sichere Betrieb über die geplante Lebensdauer von mehreren Jahrzehnten ist nur mit einer genauen Teilentladungsdiagnose, welche eine sensitive Messung und zweifelsfreie Interpretation der Ergebnisse beinhaltet, möglich. Dabei ist zu beachten, dass die von Wechselspannungsanwendungen bekannten physikalischen Zusammenhänge der Entladungsprozesse und des Einflusses von dielektrischen Grenzflächen aufgrund der veränderten Belastung mit einem zeitlich konstanten elektrischen Feld und der damit einhergehenden Raum- und Oberflächenladungsakkumulation nicht direkt übernommen werden können. Ziel dieser Arbeit ist daher die Entladungsprozesse an Defekten mit und ohne dielektrischer Grenzfläche in gasisolierten Gleichspannungssystemen zu analysieren und damit einen Beitrag für die sichere Interpretation von Teilentladungsmessungen zu leisten. Auch werden bekannte elektrische und neuartige optische Messmethoden hinsichtlich ihrer Möglichkeiten und Grenzen beim Einsatz unter Gleichspannungsbelastung untersucht. Für die experimentellen Arbeiten an drei verschiedenen Störstellen wird das schwach inhomogene Isoliersystem der Anlagen in drei Modellanordnungen nachgebildet. Die Untersuchung der ablaufenden Entladungsprozesse wird durch eine direkte Messung des Teilentladungsstroms ermöglicht. Dabei wird zwischen impulsbehafteten und impulslosen Anteilen unterschieden. Infolge von Montagefehlern oder unzureichender Materialqualität können feste, metallische Störstellen im Isoliersystem entstehen. Die experimentell betrachteten Abhängigkeiten der Entladungsprozesse von der Störstellenpolarität, dem Isoliergasdruck und der Spannungsbelastung erlauben eine Klassifizierung von vier verschiedenen Entladungsarten. Zusätzlich zu den Untersuchungen im derzeit am häufigsten verwendeten Isoliergas Schwefelhexafluorid konnte ein Vergleich der Ergebnisse mit der klimafreundlichen alternative synthetische Luft die Gemeinsamkeiten und Unterschiede bei Entladungen an festen Störstellen aufzeigen. Dabei ist insbesondere die signifikant veränderte Polaritätsabhängigkeit hervorzuheben. Der Kontakt von metallischen Partikeln mit der Feststoffisolierung kann zur Anlagerung des zuvor freibeweglichen, metallischen Defektes an der dielektrischen Grenzfläche führen. Die Ansammlung von Oberflächenladungen auf dem Feststoff beeinflusst dabei insbesondere den Entladungseinsatz. Aufgrund des zur festen metallischen Störstelle ohne Grenzfläche vergleichbaren Entladungsverhaltens im stationären Zustand ist eine Unterscheidung der Defekte anhand von Impulswiederholraten und Amplituden herausfordernd. Eine Besonderheit bei Gleichspannungsbelastung sind Entladungen, welche auf einer Gas-Feststoff-Quergrenzfläche an beschichteten Elektroden einsetzen können. Die Untersuchung der Ursachen für das Auftreten dieser Entladungen, die elektrischen und optischen Charakteristika der ablaufenden Prozesse und Strategien für die Vermeidung werden untersucht. Aus den Ergebnissen werden Prüfempfehlungen für die Teilentladungsdiagnose von gasisolierten Gleichspannungssystemen abgeleitet. Diese sind wesentlicher Bestandteil für einen zukünftigen Einsatz gasisolierter Gleichspannungssysteme in einem leistungsfähigen Elektroenergiesystem mit hoher Versorgungszuverlässigkeit. / The compact design and the independence from environmental conditions of gas-insulated systems leads to an ideal suitability of this high-voltage equipment for the use in a modern power supply system. The operation of the assets under DC voltage stress is unavoidable due to the increasing distance between the areas of power generation and consumption. The reliable operation during the estimated lifetime of several decades is only feasible with a precise partial discharge diagnosis. Hence, a sensitive measurement and a doubtless interpretation of the results is necessary. Nevertheless, it is necessary to take into account, that under alternating voltage stress established physical mechanisms of the discharge processes and the influence of dielectric interfaces cannot be adopted directly, due to the changed voltage stress with a constant electric field and the related surface and volume charge accumulation. Aim of this thesis is the analysis of defects in gas-insulated systems with and without dielectric interfaces under DC voltage stress and thereby to contribute to a reliable interpretation of partial discharge measurements. In addition, known electrical and novel optical measurement methods are investigated with respect to their capabilities and limitations when used under DC voltage stress. The experimental investigations are carried out in model electrode arrangements. The weakly inhomogeneous electrical field of the gas-insulated systems is replicated in three configurations, one for each defect investigated. The detailed analysis of the discharge processes is enabled by a direct measurement of the partial discharge currents. A distinction between impulse currents and pulseless currents is made. Due to assembly faults or insufficient material quality fixed, metallic protrusions can be created within the insulation system. The experimentally observed dependencies of the discharge processes on the polarity of the defect, the insulating gas pressure and the voltage stress permit a classification of four different types of discharge. In addition to the investigations in the most commonly used insulating gas sulphur-hexafluoride a comparison of the results with measurements in the climate-friendly alternative synthetic air are made. Derived from this, commonalities and differences in the discharge behaviour are discussed. Free moving, metallic particles can adhere to the gas-solid interface. The accumulation of surface charges at the solid insulator influences the partial discharge inception significantly. Due to the steady-state discharge behaviour, which is comparable to the fixed, metallic protrusion without contact to a dielectric interface, distinguishing between the two defects based on pulse repetition rates and amplitudes is challenging. A unique aspect under DC voltage stress are discharges at the orthogonal interface between electrode coating and insulating gas. The analysis of the causes of the occurrence of these discharges, their optical and electrical characteristics and strategies for the prevention are investigated. Derived from the results, recommendations for partial discharge diagnosis of gas-insulated DC systems are discussed. These recommendations are an essential component for the future use of this asset in a high-performance electric power system with high reliability of the power supply.

No description available.

No description available.