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: Natural disasters are unavoidable and can cause serious damage to bridges, which maylead to catastrophic losses, both human and economic. Therefore, the assessment of bridges exposedto these events is of paramount importance to identify possible mitigation needs. The objective ofthe present work is to present consistent tools that may allow us to obtain the failure probability of amasonry arch bridge under a flood event, leading to local scour. Surrogate models were implementedto ease the computational cost of the probabilistic analysis. Moreover, a stochastic parametric analysisbased on the geotechnical properties of the soil components of masonry arch bridges located inPortugal was performed. The results show the failure mechanism of the masonry arch bridges whensubjected to scour-induced settlements and the influence of soil density on the failure probabilityobtained for different flow discharge values and angles of attack. The presented methodology andderived fragility curves can be used to assess bridge performance under a flood event, thus providinguseful information for bridge management and monitoring. Resumen: Los desastres naturales son inevitables y pueden causar graves daños a los puentes, lo que puede provocar pérdidas catastróficas, tanto humanas como económicas. Por lo tanto, la evaluación de los puentes expuestos a estos eventos es de suma importancia para identificar las posibles necesidades de mitigación. El objetivo del presente trabajo es presentar herramientas consistentes que nos permitan obtener la probabilidad de falla de un puente de arco de mampostería bajo un evento de inundación, conduciendo a una socavación local. Se implementaron metamodelos para reducir el costo computacional del análisis probabilístico. Además, se realizó un análisis paramétrico estocástico basado en las propiedades geotécnicas de los componentes del suelo de los puentes de arco de mampostería ubicados en Portugal. Los resultados muestran el mecanismo de falla de los puentes de arco de mampostería cuando se someten a asentamientos inducidos por socavación y la influencia de la densidad del suelo en la probabilidad de falla obtenida para diferentes valores de caudal y ángulos de ataque. La metodología presentada y las curvas de fragilidad derivadas se pueden usar para evaluar el desempeño del puente bajo un evento de inundación, proporcionando así información útil para la gestión y el monitoreo del puente.

Abstract: Summary The main objective was aimed at determining the biomass production from water based on water relations, levels of water consumption of the species, and climate variables that affect the formation of biomass and soil present and specifically it focused on two forage crops which were Forage Oats (Avena sativa L.) and ryegrass (Lolium perenne). The solution to the problem is based on AquaCrop model (FAO) Steduto et al, (2009) which was recently proposed for the determination of both biomass and agricultural production from water transpired by herbaceous species, this is gather scientific and technological advances on the effect of water in the estimation of crop production has been achieved in recent years. In the present research we have identified key variables AquaCrop model input for the two species mentioned, through field research conducted using the methodology gradient Hanks et al., (1980), and a new methodology proposal for determining water stress. A total of 18 major experiments were developed to generate the levels of biomass production of forage oats and ryegrass, determining 32 variables or parameters for each crop that requires the model to estimate the biomass produced by the forage and pasture. Furthermore, the engine for determining crop production handling model is the concept of crop water productivity (WP) which is a conservative parameter resulting in greater strength, besides water productivity is normalized in two ways: (1) the climate are represented by the reference evapotranspiration (ET0) and (2) the content of CO2 in the atmosphere. These normalization allow abstract both climate and CO2 content over time, whereby, the engine model turns out to be an essential tool to estimate both the biomass and production, even considering the effects of global climate change. The experiments were conducted mainly during the years 2008-2013 in “Centro de Investigación Tibaitatá (AGROSAVIA)” located in the savannah of Bogota (Colombia). For forage oats were developed five cycles and ryegrass crops three complete cycles, with seven, four and two cuts were made respectively. Based on the information provided in the field, forage oats and ryegrass crops were calibrated and validated for AquaCrop model reaching adjustments R2=0.92, RMSE=1,86t.ha-1, NRMSE=17.67%, EF=0.91, d=0.97 for forage oat and R2=0.97, RMSE=0,47t.ha-1, NRMSE=13.6%, EF=0.88, d=0.98 for ryegrass. Two synthetic crops were determined one for each specie, which are "prototypes" for estimating biomass by the water use in different conditions of crops. The total biomass was determined to forage oats at 22.2 t.ha-1 on average with peaks that can reach up to 27 t.ha-1 in the production environment of the savannah of Bogota. For ryegrass total biomass reached levels of up to 9 t.ha-1 on average with peaks that can reach up to 9,9 t.ha-1 for the period from planting to first cut, and 6 t.ha-1 for others cuts. The intrinsic water footprint for fodder oats was determined in 175 L.kg-1 and 442 ryegrass L.kg-1 and 431 L.Kg-1. This research is novel because implemented scientific and technological advances of AquaCrop in forage crops, for the determination of the biomass by the water, because until this had not been calibrated and validated for the model, special biophysical considerations forage crops driving differently elements like crop production and harvest index. In addition to the large expanses of areas that exist today in the world of forages and pastures, which can be incorporated into local, regional or global studies biomass production, efficient water use, water consumption and determination of requirements, carbon sequestration, and determining the effects of changes in the coverage of pasture and forage in the global climate change. Resumen: El objetivo principal estuvo orientado a la determinación de la producción de biomasa a partir del agua con base en las relaciones hídricas, los niveles de consumo de agua de las especies, y las variables del clima que inciden en la formación de biomasa y el suelo presentes y se centró específicamente en dos cultivos forrajeros: Avena Forrajera (Avena sativa, L.) y Raigrás (Lolium perenne). La solución al problema se basa en el modelo AquaCrop (FAO) Steduto et al, (2009) el cual fue propuesto para la determinación tanto de la biomasa como del rendimiento a partir del agua transpirada por las especies herbáceas, en este se reúnen los avances científicos y tecnológicos que sobre el efecto del agua en la estimación de la producción de cultivos se ha logrado en los últimos años. En el presente trabajo de investigación se han parametrizado las variables de entrada al modelo AquaCrop, para las dos especies mencionadas, por medio de investigación de campo realizada con la metodología del gradiente de Hanks et al, (1980), y con una nueva metodología propuesta para la determinación del estrés hídrico. Se desarrollaron un total de 18 experimentos principales generando los niveles de producción de biomasa de avena forrajera y raigrás, determinando 32 parámetros para cada uno de los cultivos que requiere el modelo para la estimación de la biomasa producida por las especies forrajeras y pastos. El modelo AquaCrop implementa varios avances sobre el conocimiento del desarrollo de cultivos, como la separación de la evapotranspiración en evaporación del suelo y la transpiración del cultivo, la consideración independiente de la producción del cultivo en biomasa y el índice de cosecha. Para la determinación del desarrollo del cultivo se maneja el porcentaje de cobertura del dosel en vez del índice de área foliar (IAF). Además, el motor para la determinación de la producción del cultivo que maneja el modelo es el concepto de la productividad hídrica del cultivo (WP) la cual es un parámetro conservativo que redunda en mayor robustez, la productividad hídrica además se normaliza bajo dos aspectos que son el clima representado por la evapotranspiración de referencia (ET0) y el contenido del CO2 en la atmósfera. Con base en la información establecida en campo se calibraron y validaron los cultivos de avena forrajera y raigrás para el modelo AquaCrop alcanzando ajustes de R2=0,92, RMSE=1,86t.ha-1, NRMSE=17,67%, EF=0,91, y d=0,97 para avena forrajera y de R2=0,97, RMSE=0,47t.ha-1, NRMSE=13,6%, EF=0,88, y d=0,98 para raigrás. Se determinaron dos cultivos sintéticos uno para cada especie, los cuales constituyen los “prototipos” que son el punto de partida para la estimación de la biomasa a partir del uso del agua en diferentes condiciones de los cultivos mencionados. La biomasa total para avena forrajera fue determinada en 22,2t.ha-1 en promedio con valores máximos que pueden llegar a alcanzar hasta 27t.ha-1 en el entorno productivo de la sabana de Bogotá. Para raigrás la biomasa total alcanzó niveles de hasta 9t.ha-1, para el período de siembra a primer corte, y de 6t.ha-1 para los cortes posteriores al primero. La huella hídrica intrínseca para avena forrajera fue determinada en 175L.kg-1 y para raigrás en 442L.kg-1 y 431L.Kg-1. El presente trabajo es novedoso por la implementación de los avances científicos y tecnológicos de AquaCrop en cultivos forrajeros, para la determinación de la biomasa a partir del agua, pues hasta la presente no habían sido calibrados y validados para el modelo, las consideraciones biofísicas especiales de los cultivos forrajeros que manejan de forma diferente elementos como la producción de cosecha y el índice de cosecha. Además por las grandes extensiones de áreas que existen hoy en el mundo de cultivos forrajeros y pastos, las cuales pueden ser incorporadas en estudios locales, regionales o globales de producción de biomasa, eficiencia en el uso del agua, consumos y determinación de requerimientos hídricos, captura de carbono, y determinación de los efectos de las variaciones de las coberturas de pastos y forrajes en el cambio climático global.

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: Water quality sampling is a key element in tracking water quality monitoring objectives. However, frequencies adapted by different agencies might not be sufficient to provide an accurate indication of water quality status. In this study, data from low- and high-resolution water quality datasets were analyzed to determine the extent to which monitoring objectives could be achieved with different sampling frequencies, with a view to providing recommendations and best practices for water quality monitoring frequency in places with limited resources with which to implement a high-frequency monitoring plan. Water quality data from two watersheds (Maumee River and Raisin River) located in the Western Lake Erie Basin (WLEB) were used since these watersheds have consistent records over substantial periods of time, and the water quality data available have a high resolution (at least daily). The water quality constituents analyzed included suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and nitrate + nitrite (NO2+3). Sources of pollutants for watersheds located in the WLEB include contributions from point sources like discharges from sewage treatment plants and non-point sources such as agricultural and urban storm runoff. Weekly, bi-weekly, monthly, and seasonal datasets were created from the original datasets, following different sampling rules based on the day of the week, week of the month, and month of the year. The resulting datasets were then compared to the original dataset to determine how the sampling frequency would affect the results obtained in a water quality assessment when different monitoring objectives are considered. Results indicated that constituents easily transported by water (such as sediments and nutrients) require more than 50 samples/year to provide a small error (< 10%) with a confidence interval of 95%. Monthly and seasonal sampling were found appropriate to report a stream’s prevailing water quality status and statistical properties. However, these resolutions might not be sufficient to capture longterm trends, in which case bi-weekly samples would be preferable. Limitations of lowresolution sampling frequency could be overcome by including rainfall events and random sampling during specific time windows as part of the monitoring plan.

Abstract: Water quality sampling is a key element in tracking water quality monitoring objectives. However, frequencies adapted by different agencies might not be sufficient to provide an accurate indication of water quality status. In this study, data from low- and high-resolution water quality datasets were analyzed to determine the extent to which monitoring objectives could be achieved with different sampling frequencies, with a view to providing recommendations and best practices for water quality monitoring frequency in places with limited resources with which to implement a high-frequency monitoring plan. Water quality data from two watersheds (Maumee River and Raisin River) located in the Western Lake Erie Basin (WLEB) were used since these watersheds have consistent records over substantial periods of time, and the water quality data available have a high resolution (at least daily). The water quality constituents analyzed included suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and nitrate + nitrite (NO2+3). Sources of pollutants for watersheds located in the WLEB include contributions from point sources like discharges from sewage treatment plants and non-point sources such as agricultural and urban storm runoff. Weekly, bi-weekly, monthly, and seasonal datasets were created from the original datasets, following different sampling rules based on the day of the week, week of the month, and month of the year. The resulting datasets were then compared to the original dataset to determine how the sampling frequency would affect the results obtained in a water quality assessment when different monitoring objectives are considered. Results indicated that constituents easily transported by water (such as sediments and nutrients) require more than 50 samples/year to provide a small error (< 10%) with a confidence interval of 95%. Monthly and seasonal sampling were found appropriate to report a stream’s prevailing water quality status and statistical properties. However, these resolutions might not be sufficient to capture longterm trends, in which case bi-weekly samples would be preferable. Limitations of lowresolution sampling frequency could be overcome by including rainfall events and random sampling during specific time windows as part of the monitoring plan.

Abstract: Resilience has become a fundamental paradigm for communities to deal with disaster planning. Formal methods are used to prioritise and decide about investments for resilience. Strategies and behaviour need to be developed that cannot be based on formal modelling only because the human element needs to be incorporated to build community resilience. Participatory modelling and gaming are methodological approaches that are based on realistic data and address human behaviour. These approaches enable stakeholders to develop, adjust, and learn from interactive models and use this experience to inform their decision?making. In our contribution, we explore which physical and digital elements from serious games can be used to design a participatory approach in community engagement and decision?making. Our ongoing research aims to bring multiple stakeholders together to understand, model, and decide on the trade?offs and tensions between social and infrastructure investments toward community resilience building. Initial observations allow us as researchers to systematically document the benefits and pitfalls of a gamebased approach. We will continue to develop a participatory modelling exercise for resilience planning with university graduate students and resilience experts within academia in Christchurch, New Zealand. Resumen: La resiliencia se ha convertido en un paradigma fundamental para que las comunidades afronten la planificación de las catástrofes. Se utilizan métodos formales para priorizar y decidir sobre las inversiones en resiliencia. Es necesario desarrollar estrategias y comportamientos que no pueden que no pueden basarse únicamente en modelos formales, ya que es necesario incorporar el elemento humano para aumentar la resiliencia de la comunidad. La modelización participativa y los juegos son enfoques metodológicos que se basan en datos realistas y abordan el comportamiento humano. Estos enfoques permiten que las partes interesadas desarrollen, ajusten y aprendan de los modelos interactivos y utilicen esta experiencia para informar su toma de decisiones. En nuestra contribución, exploramos qué elementos físicos y digitales de los juegos seriados pueden utilizarse para diseñar un enfoque participativo en el compromiso y la toma de decisiones de la comunidad. Nuestra investigación en curso pretende reunir a múltiples partes interesadas para comprender, modelar y decidir sobre las compensaciones y tensiones entre las inversiones sociales y las de infraestructura para el desarrollo de la resiliencia de la comunidad. Las observaciones iniciales nos permiten, como documentar sistemáticamente las ventajas y los inconvenientes de un enfoque basado en el juego. Seguiremos desarrollando un ejercicio de modelización participativa para la planificación de la resiliencia con estudiantes universitarios y expertos en resiliencia dentro de universitarios y expertos en resiliencia de Christchurch (Nueva Zelanda).

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: 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: 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.