Este trabajo se realizó mediante una investigación de tipo ingeniería didáctica, para la cual se retomaron elementos del diseño realizado por Rueda y Niño (2013) con el software Cabri LM, adaptándolo a las herramientas disponibles en el software CaRMetal; esta adaptación incluyó la reprogramación del funcionamiento de las actividades, la automatización de los actos de devolución y la reestructuración del análisis a priori. El trabajo pretende observar hasta qué punto el software CaRMetal posibilita la automatización de actos de devolución.

The Interaction of electromagnetic waves with dielectric bodies and metals has been extensively studied because of its importance to problems including propagation through rain or snow, scattering by and detection of air borne particles, coupling to missiles with plasma plumes or dielectric-filled apertures, performance of communication antennas in the presence of dielectric and magnetic inhomogeneities, and medical diagnostics and power absorption in biological bodies. Computational electromagnetics methods (CEM) offer and indispensable tool for calculating the electromagnetic scattering from an internal field distribution of arbitrarily shaped, inhomogeneous, dielectric bodies. The aim of this thesis is the study and simulation of a RF coils system design by developing a novel parallel fast Method of Moments (MoM) modeling approach suitable for the simulation of dielectric bodies and metals. The parallel fast MoM implementation uses volume and surface basis functions with special properties appropriate for the representation of flux current densities for perfect electric conductors (PEC) and dielectrics. The results obtained with our modeling method were confirmed by comparisons with analytical solutions and other commercial software results, yielding very good agreement. The RF coil is employed in high field Magnetic Resonance Imaging (MRI) to obtain high quality brain images. Among all the clinical imaging techniques, MRI stands as a noninvasive technique that provides accurate, detailed anatomic images, which has had a major impact in the diagnosis of human diseases. MRI is a widely use soft-tissue imaging modality that has involved over the past several years into a powerful and versatile medical diagnostic tool capable of providing in-vivo diagnostic images of human anatomy. Current research areas in MRI system design are driven by the need to obtain detailed high resolution images with improved image signal-to-noise ratio (SNR) at a given magnetic field strength. One of the most critical factor that influences the quality and resolution of the MRI is the homogeneity of the RF field. To this end, this requirement demands the development of high performance MRI radio frequency (RF) coils and a standard procedure for enhancing the uniformity of the field directly at the modeling stage of the RF Coil.

Abstract: The standard IEC 61400-1, v.4.0 proposes at appendix J a method to determine the probability of extreme winds, based on the simulation of artificial cyclones and the theory of gradient wind. This method considers marginal statistical distributions for 5 main descriptors of cyclones (pressure depth, radius of maximum wind speed, translation speed, angle to the point of reference and mini-mum distance), a “modified orthogonal decomposition” to generate artificial cyclones and its own formulas to determine surface wind, cumulative probabilities and annual maximum surface wind. This research pursued to implement and to validate the standard at North West Pacific. Due to the difficulty and highly empirical elements of IEC 61400-1, v.4.0, it was required to modify it and include in the model other inputs such as well known statistical distributions after testing them, Nataf trans-formation (ERANataf) to generate artificial cyclones and empirical cumulative distribution functions to determine the probability of annual maximum surface wind. For the verification and validation, the results of 9 locations distributed in South Korea, Japan, HongKong and Taiwan were compared with the database of the Joint Typhoon Warning Center and theRSMC-Tokyo. The implementation of this research underestimated surface wind in all the locations.Simultaneously, the greatest contribution of input variables to sensitivity was more frequent from super index B of Holland. It would be desirable to continue validating this standard (that is presumed to have a global application), to understand the challenges of its theory during the computation of surface wind from gradient wind and to overcome the issues of its implementation.

Abstract: This Master thesis presents a decentralized DDC strategy for major household appliances in Berlin. It exploits their power flexibility by means of three key indicators and supported by artificial intelligence. It has been examined whether those appliances may be used in a decentralized frequency regulation successfully. The appliances have been divided into two groups according to their operating characteristics- Thermal and Sequential Loads. This work also inquiries about the suitability of the control strategy to overcome power imbalances caused by PV generation. To answer this question, different seasonal and consumption scenarios have been analyzed. The control strategy is implemented using a modular approach. For this purpose, three main stages have been defined and divided into smaller units. For the implementation of these units Pandapower, MATLAB, and its toolbox MATPOWER have been used. The first stage is the power consumption forecast using a Neural Network. A feed-forward Network has been designed to estimate a day-ahead consumption profile for each household. At the second stage the Sequential Loads optimal scheduling takes place. A Genetic Algorithm optimizes the Sequential Loads turn on time based on householder preferences and characteristics. At the last stage the Dynamic Demand Control strategy takes place. On one hand, LSI stands for the characteristics of the appliances and for the user´s comfort. On the other hand, GSI and GCI represent the grid state from a technical and economic point of view. To validate the method a suitable network has been implemented. This network has 1800 households and includes 198 residential rooftop PV systems. Besides, several scenarios have been designed to test and compare the control strategy under different conditions. Influencing factors such as Energy Consumption Patterns and the size of the higher-level distribution grid are been modified. The analysis of the simulations shows that the proposed DDC strategy succeeds in frequency stabilization with flexible loads. The Energy Consumption Patterns play a relevant role to achieve this regulation. ECP d- the most realistic pattern, allows a successful control during the entire year with a significant low X value equal 10. These positive results allow for the conclusion that a decentralized control strategy with no information exchange can be implemented in a city like Berlin. Resumen: Esta tesis de maestría presenta una estrategia de control dinámica de demanda descentralizada para los principales electrodomésticos en la ciudad de Berlín. Esta estrategia explota la flexibilidad energética de los electrodomésticos mediante tres indicadores clave y al apoyarse en inteligencia artificial. Se ha examinado si esos aparatos pueden utilizarse con éxito en la regulación de frecuencia descentralizada. Los aparatos se han dividido en dos grupos según sus características de funcionamiento: cargas térmicas y secuenciales. Este trabajo también indaga sobre la idoneidad de la estrategia de control para superar los desequilibrios energéticos provocados por la generación fotovoltaica. Para responder a esta pregunta se han analizado diferentes escenarios estacionales y de consumo. La estrategia de control se implementa mediante un enfoque modular. Para ello, se han definido tres etapas principales y se han dividido en unidades más pequeñas. Para la implementación de estas unidades se han utilizado Pandapower, MATLAB y su aplicativo MATPOWER. La primera etapa es la pronostico del consumo de energía mediante una red neuronal. Se ha diseñado una red feed-forward para estimar el perfil de consumo diario para cada hogar. En la segunda etapa tiene lugar la programación óptima de cargas secuenciales. Un algoritmo genético optimiza el tiempo de activación de las cargas secuenciales en función de las preferencias y características del hogar. En la última etapa se lleva a cabo la estrategia de control dinámico de la demanda. Por un lado, LSI representa las características de los electrodomésticos y la comodidad del usuario. Por otro lado, GSI y GCI representan el estado de la red desde un punto de vista técnico y económico. Para validar el método se ha implementado una red adecuada. Esta red tiene 1800 hogares e incluye 198 sistemas fotovoltaicos residenciales en tejados. Además, se han diseñado varios escenarios para probar la estrategia de control en diferentes condiciones. Se modifican factores de influencia como los Patrones de Consumo de Energía y el tamaño de la red de distribución de nivel superior. El análisis de las simulaciones muestra que la estrategia DDC propuesta tiene éxito en la estabilización de frecuencia con cargas flexibles. Los Patrones de Consumo de Energía juegan un papel relevante para lograr esta regulación. ECP d- el patrón más realista, permite un control exitoso durante todo el año con un valor X bajo significativo igual a 10. Estos resultados positivos permiten concluir que una estrategia de control descentralizado sin intercambio de información se puede implementar en una ciudad como Berlín.

Abstract: In the past, when power systems did not incorporate a considerable amount of distributed generation units, the almost passive behavior of the distribution networks could be reasonably represented by static load models (e.g., the exponential model), because they had relatively little impact on power system stability. Therefore, from a transmission perspective, the distribution systems could be seen as an aggregated load for bulk power system stability studies. However, in modern systems, the impact of distributed generation units can no longer be neglected. The static models cannot represent the dynamics of the active distributed networks, which are now increasingly spread across power systems. However, modeling active distribution networks in detail is not feasible due to information exchange restrictions between transmission and distribution system operators, in addition to the great computational effort that it would take. This thesis proposes an alternative black-box, simulation-based methodology to identify dynamic equivalents of active distribution networks focused on long-term voltage stability studies for bulk power systems. The methodology is based on model identification techniques and Hammerstein-Wiener models. The approach depends only on variables measured at the boundary buses, which prevents the need to have previous knowledge about the system, as is the case with greybox models. Furthermore, to avoid heavy-duty nonlinear model techniques, such as artificial neural networks, which are challenging to implement and use in a rather conservative sector such as power systems planning and operation, the proposed methodology keeps a transparent relationship to linear systems. The results and conclusions are derived from time-domain simulations on the IEEE test system for voltage stability assessment, the Nordic test system. It is concluded that the dynamic equivalents are able to reproduce accurately the nonlinear behavior of the active distribution networks. Resumen: En el pasado, cuando los sistemas de energía no incorporaban una cantidad considerable de unidades de generación distribuida, el comportamiento casi pasivo de las redes de distribución podía representarse razonablemente mediante modelos de carga estática (por ejemplo, el modelo exponencial), porque tenían un impacto relativamente pequeño en la energía. estabilidad del sistema. Por lo tanto, desde una perspectiva de transmisión, los sistemas de distribución podrían verse como una carga agregada para los estudios de estabilidad del sistema de energía a granel. Sin embargo, en los sistemas modernos, el impacto de las unidades de generación distribuida ya no puede pasarse por alto. Los modelos estáticos no pueden representar la dinámica de las redes distribuidas activas, que ahora se distribuyen cada vez más en los sistemas de energía. Sin embargo, modelar las redes de distribución activas en detalle no es factible debido a las restricciones de intercambio de información entre los operadores de los sistemas de transmisión y distribución, además del gran esfuerzo computacional que requeriría. Esta tesis propone una metodología alternativa basada en simulación de caja negra para identificar equivalentes dinámicos de redes de distribución activas enfocadas en estudios de estabilidad de voltaje a largo plazo para sistemas de energía a granel. La metodología se basa en técnicas de identificación de modelos y modelos de Hammerstein-Wiener. El enfoque depende únicamente de las variables medidas en los buses delimitadores, lo que evita la necesidad de tener conocimientos previos sobre el sistema, como es el caso de los modelos de caja gris. Los resultados y las conclusiones se derivan de simulaciones en el dominio del tiempo en el sistema de prueba IEEE para la evaluación de la estabilidad de voltaje, el sistema de prueba nórdico.

Abstract: This project presents three-dimensional conceptual and numerical flow models of a gascondensate field in the foothills region of the Eastern Llanos Basin in Colombia. The Eastern Llanos Basin has been the subject of diverse studies for hydrocarbon exploitation. Over the past decade, this region has been assessed for its geothermal potential in currently exploited oil & gas fields. A gas-condensate field located in the foothills of the basin represents a promising opportunity to produce geothermal energy. The conceptual and numerical models integrate geological, geophysical, geochemical and well data to enhance the understanding of the geothermal system in a sedimentary environment. The Leapfrog Geothermal model shows that the gas-condensate field presents a structurally complex architecture, where hydrocarbons and water accumulate in an relatively permeable reservoir. Well data exhibit a constant geothermal gradient, indicating conductive heat transfer. Based on geochemical data and hydrological analyses, it is identified that meteoric recharge occurs in the Andean orogenic belt and fluid flows from NW to SE. TOUGH2 numerical simulations are developed to generate a natural state model and geothermal production scenarios, which give an estimation of water extraction in the field. The thermal and hydraulic parameters were extracted from published experimental and well data. In order to simplify this first geotermal model, and reduce the number of parameters, it is assumed that the field is completely saturated with water. The natural state model temperature field is concordant with measured well data and simulated mass flow direction confirm expected patterns. Production scenarios demonstrate that it is possible to extract water at more than 90 °C without termal breakthrough during the 30 years simulation. Thermal power calculations yield two optimistic scenarios with more than 30 MWth of heat production, and a conservative scenario with approximately 6 MWth. The conservative scenario provides a better approach to reality with current water production. Thus, this project presents the basis for further studies on geothermal development in actively exploited hydrocarbon fields.

Abstract: This thesis addresses the numerical optimization of the design and scheduling of a biomethane plant integrated with a reversible solid oxide cell, amongst other technologies, that allow the processing of biogas coming from OFMSW anaerobic digestion as to maximize profitability on a yearly basis under different circumstances. The optimization model is carried out through a mixed integer linear program as to obtain the adequate sizes of the different technologies that compose the integrated energy plant whilst taking advantage of the energy and material stream interactions to reach optimal financial feasibility. The inclusion of a reversible oxide fuel cell allows the system to work in different modes as in Power-to-gas and Gas-to-power, generating interest on to the different services that the system can provide to the gas and electricity grids and most importantly to a future decarbonized energy scenario. Furthermore, inclusion of linear models for an amine scrubbing section for biomethane upgrading, a photovoltaic solar field, gas and heat storage units, a battery energy storage system and a biogas boiler into the MILP is carried out as they are part of the technologies in study for the integrated energy plant. The seasonal variability for gas and electricity prices, part load performances, size effects, weather related data, and technological modelling of components are all part of the challenges to be tackled as to obtain a MILP able to compute accurate, adequate and optimal solutions for the design and scheduling problem whilst subjected to technological, environmental and operational constraints. Resumen: Esta tesis se centra en la optimización numérica del diseño y operación de una planta de biometano integrada con una celda de hidrogeno reversible, entre otras tecnologías, que permiten el procesamiento de biogás proveniente de la digestión anaeróbica de material orgánico con el objetivo de maximizar las ganancias en temporalidad anual ante diferentes circunstancias. El modelo de optimización se lleva a cabo con un algoritmo de programación lineal de entornos mixtos para obtener los tamaños de diseño adecuados de las diferentes tecnologías que componen a la planta integrada de energía mientras se toma ventaja de las interacciones entre cada flujo de energía y/o materia para obtener la mas óptima viabilidad económica. La inclusión de una celda reversible de hidrógeno permite al sistema trabajar en diferentes modos como electricidad a gas o gas a electricidad, generando interés en los distintos servicios que el sistema puede proveer a las redes de gas y electricidad y aun más importante a un futuro escenario mundial de energético descarbonizado. Mas aún, la inclusión de modelos lineales como un sistema de mejora de la calidad del biometano mediante absorción con aminas, un campo de energía solar fotovoltaica, unidades de almacenamiento de gas y calor, un sistema de almacenamiento de energías mediante baterías y una caldera de biogás en el modelo de programación lineal es llevado a cabo pues son parte de las tecnologías en estudio para la planta energética integrada. La variación estacional por los precios de gas y electricidad, desempeño a cargas parciales, efectos de tamaños, data ambiental, y el modelado tecnológico de los componentes son parte de los retos a ser resueltos para poder obtener un MILP capaz de computar precisas, adecuadas y optimas soluciones para el problema de diseño y operación mientras se encuentra sujeto a restricciones tecnológicas, ambientales y operacionales.

Abstract: The main aim of this study is to investigate utilising root improve the interfacial strength of pin-like integrated hybrid composite architectures to metal structures. Joints are critical elements in aircraft structures and require special consideration due to their vital role in the structural integrity of airframes. Although bonded and bolted systems are used commonly in engineering applications, pinning technologies have shown tremendous potential for hybrid joints. Nonetheless, exploring complex pin geometries has been challenging when considering associated manufacturing techniques. Using pre-preg constrains the topography of the pin, while vacuum resin infusion offers more possibilities to manufacture complex hybrid joints. This study develops an experimental methodology to fabricate hybrid joints with arbitrary pin geometry using Selective Laser Melting (SLM) and resin infusion techniques. First, titanium parts with four inclination angles of 0°, 20°, 45° and 80° were fabricated using the SLM method, and their surface roughness was examined using a profilometer. Then, dry unidirectional carbon fabrics were stacked into pins in a hand layup process followed by epoxy infusion in a vacuum chamber. The cross-section of the fabricated joints was inspected employing an optical microscope, SEM and ?CT-scanner. The pin angle shape of the resin and fibre alignment impacted the geometry and rich area in the insertion region. Manufacturing defects such as pores were present in the composite with a high density closer to the titanium composite bondline. Despite those setbacks, resin-infused composites were integrated into highly tilted pins such as 45° or 80°. This precedent demonstrated that root like pins could also be co-cured with composites. The effect of pin angle on the mechanical performance of hybrid joints was experiment ally investigated. The load-displacement response of various specimens was recorded while joints were subjected to pull-off tensile loading. Experimental results showed how the pin angle affects the stiffness, strength and strain energy of joints. Damage initiation and propagation in the hybrid joints were also investigated by examining the fracture surfaces and the relationship between damage mechanisms and pin angles. Significant matrix crushing was realised in joints with 45° and 80° inclined pins with p in rupture only observed in the latter. Furthermore, a numerical study was conducted to explore the response of multiple root-like pin geometries. A 2D model was developed and validated for parametric study based on the experimentally measured interfacial strength. This bidimensional model accurately captured the experimental load-displacement curves for joints under tensile load. After calibration, the model was used to study the effect of three branches geometrical features of a rootlike pin on the mechanical behaviour of the hybrid joint. It was demonstrated that the diameter, length and location of side branches play a vital role in the failure behaviour of joints by affecting the stress distribution in composite adherend. Based on the findings from this study, it can be concluded that the integration of complex pin shapes and composite are likely using resin infusion techniques. Moreover, root like pins with optimised topology can be incorporated into hybrid joints to enhance bonding strength and failure behaviour.

Abstract: Information regarding the state of bridges is fundamental for maintaining a satisfactory performance level, given that deterioration may lead to bridge failure and thus, increased costs. Bridges face harsh environmental conditions and natural disasters are often inevitable and can be one of the main reasons for bridge collapse. Consequences from flooding events (e.g., scour) are responsible for a large percentage of failures in bridge structures. Therefore, the assessment of bridges susceptible to these phenomena is of utmost importance to identify possible mitigation needs. The objective of the present research is to present a consistent framework to obtain fragility curves associated with the inplane behavior of masonry arch bridges (MAB) under flood hazard. By implementing metamodeling techniques to the probabilistic analysis, a computational cost-efficient framework is proposed which is employed on a MAB “Ponte da Vala do Carregado” located in Portugal. A two-dimensional numerical model was constructed where the random variables that affect the structural capacity and the scouring process were considered. Finally, a parametric analysis, based on the geometric variations of the bridge structure and geotechnical variations of the foundation material (bed material), was implemented. The fragility curves show that failure probability increases when flow discharge increases, especially when the skew flow was considered. This will allow assessing the performance of bridges that may affect the network efficiency at important sections of the roadway system if damaged by a flood event. Resumen: La información sobre el estado de los puentes es fundamental para mantener un nivel de desempeño satisfactorio, dado que el deterioro puede conducir a la falla del puente y, por ende, a un aumento de los costos. Los puentes enfrentan duras condiciones ambientales y los desastres naturales a menudo son inevitables y pueden ser una de las principales razones del colapso del puente. Las consecuencias de las inundaciones (por ejemplo, la socavación) son responsables de un gran porcentaje de fallas en las estructuras de los puentes. Por lo tanto, la evaluación de puentes susceptibles a estos fenómenos es de suma importancia para identificar posibles necesidades de mitigación. El objetivo de la presente investigación es presentar un marco consistente para obtener curvas de fragilidad asociadas con el comportamiento en el plano de puentes de arco de mampostería (MAB) bajo peligro de inundación. Mediante la implementación de técnicas de metamodelado para el análisis probabilístico, se propone un marco computacional rentable que se emplea en un MAB ""Ponte da Vala do Carregado"" ubicado en Portugal. Se construyó un modelo numérico bidimensional donde se consideraron las variables aleatorias que afectan la capacidad estructural y el proceso de socavación. Finalmente, se implementó un análisis paramétrico, basado en las variaciones geométricas de la estructura del puente y las variaciones geotécnicas del material de cimentación (material del lecho). Las curvas de fragilidad muestran que la probabilidad de falla aumenta cuando aumenta la descarga del flujo, especialmente cuando se considera el flujo sesgado. Esto permitirá evaluar el desempeño de los puentes que pueden afectar la eficiencia de la red en secciones importantes del sistema vial si se dañan por una inundación.

Abstract: The constant evolution of power systems and their protection and control systems has brought the need to investigate different concepts that could help improve the implementation and testing of protection and control systems during the complete lifecycle of electrical substations. Centralized protection and control system is a concept that has been under study for many years already but has gained more force lately, thanks to the evolution of computing technology and the more substantial influence of the standard IEC61850 in electrical substations. This thesis has studied the centralized protection and control systems starting with the development of a market availably. The result shows that even though the general concept between the available systems is the same, the specific architecture depends on the technology used to implement the centralized concept. The result also shows that the two technologies leading the market availability are the SASensor from Locamation and the SSC600 from ABB. The technologies virtualization and Synaptec’s Refase system are also investigated in this thesis. Protection and control test methodologies do also depend on the technology to be tested. Therefore, this thesis shows an overall protection and control testing lifecycle analysis of a centralized protection and control system. The architecture of the reference system used for the testing lifecycle evaluation has similarities to a decentralized digital substation architecture. Using that kind of architecture allows fully IEC61850 based protection and control testing, as the results have shown it. Therefore, knowledge, tools, and procedures developed for decentralized digital substations also apply to the centralized concept. The last part of this work presents a practical application example that uses the SSC600 as a protection and control central unit. The device configuration is based on a power system example designed for the thesis. The IEC61850 system engineering of the system and test procedures are part of the results of the practical part.