Renewable energy resource self-intervention control technique using Simulink/Stateflow modeling

Hybrid Renewable Energy Complementary Systems are gaining popularity as electricity power generation system. The Hybrid Renewable Energy Complementary Systems introductory was to overcome the intermittency during the energy harvesting process. Therefore, solar photovoltaic and wind turbine generator has been seen as one of the most promising Hybrid Renewable Energy Complementary System to overcome the intermittency compare to a typical Hybrid Renewable Energy System. The integration of solar photovoltaic and wind turbine generator as Hybrid Renewable Energy Complementary System can play an important role to reduce the dependency on the fossil fuel for electricity power generation and are seen as a solution to improve the shortage of electricity due to increasing demand. Thus, the advantages of Hybrid Renewable Energy Complementary Systems have gained attention from many researchers around the world. Research to improve the complexity complementary system performance is necessary to achieve well design control and autonomous system operation and systematic energy management in the system. With that, this paper presents a new voltage-divider balancing switching technique to control the self-intervention switching for the Hybrid Renewable Energy Complementary System. The self-intervention control strategy of the Hybrid Renewable Energy Complementary System is coordinated using the Simulink/Stateflow process. The Simulink/Stateflow modelling performs under different preset conditions which are based on the analogue voltage reading from the input of the Hybrid Renewable Energy Complementary System resources. Simulation results demonstrate the validity of the proposed research to control the self-intervention of the Hybrid Renewable Energy Complementary System under the preset conditions

Design and investigations of MPPT strategies for a wind energy conversion system based on doubly fed induction generator

The purpose of this work is to design and to discuss various strategies to optimize the production of a wind energy conversion chain based on the doubly fed induction generator (DFIG), by capturing the maximum power at the wind turbine, using maximum power point tracking (MPPT) and pitch control. The proposed controls allow the generator to monitor the optimal operating points of the turbines regardless of wind speed variations, system parameters disturbance, and parameters variation. Simulation of WECS based on a 1.5 MW wound rotor induction generator under MATLAB/SIMULINK is carried out using the PI controller (PIC), RST controller and fuzzy logic controller (FLC). Analysis and comparisons are made for different operating scenarios: Reference tracking, robustness under variable wind speed conditions and parameters variation. The application of FLC provides a very interesting outcome for the robustness and the dynamic challenges

Methodology for the evaluation and design of projects considering multiple criteria and uncertainty. Application to the development of energy projects in rural areas

Tesi en modalitat de compendi de publicacionsIn 2015, the United Nations defined the Sustainable Development Goals in a transition towards a world without poverty and where human rights, equity and sustainability are prioritized. In particular, modern energy services are considered crucial not only to achieve universal access to energy by 2030, but due to their contribution to alleviate chronical poverty, reduce food insecurity, promote the access to modern information in schools and enhance the start of productive activities. However, the aim of global access by 2030 is still far from being complete, with more than 700 million people living in rural areas without access to electricity and using firewood and other polluting traditional biomass for cooking and heating. Decentralized energy systems are gaining attention as a more feasible solution than grid extension to provide energy to rural and inaccessible areas. The evaluation and design of decentralized systems is a complex process that needs to take into account multiple alternatives and criteria to ensure a long-term sustainability, but usually available studies in literature focus exclusively in technical and economic aspects. Also, the minority of studies following a multicriteria decision-making approach underestimate the effect of the potential lack of confidence of the experts and users consulted to weight the importance of each criterion or to evaluate a specific alternative. In this context, the objective of this thesis is to develop multicriteria procedures considering uncertainty to increase the robustness of the results. These procedures are applied to projects that foster access to energy services and promote therefore the development of rural and underprivileged areas. The thesis begins with two multicriteria procedures presented for the evaluation and the design, respectively, of rural electrification projects. These procedures are applied to two real case studies in Peru and Nigeria. Both applications provide valuable insights, for local authorities and other promoters of electrification systems in similar contexts, regarding which technologies and configurations to use in determined circumstances. At the same time, the analysis carried out enable an improvement regarding the robustness of results through the consideration of the lack of confidence of the opinions collected about the importance of the criteria and the evaluation of the alternatives. In this regard, A Methodology for Multicriteria Decision-making considering Uncertainty (MIMDU) is then developed based on fuzzy numbers to include the lack of confidence experts and users might have when weighting a criterion or evaluating an alternative. The methodology designed includes a novel procedure to quantify human opinions with non-pre-defined fuzzy numbers and a systematic process to calculate diverse rankings of alternatives and provide complimentary information that leads to a more robust decision-making. Indeed, the potential of the methodology is illustrated with an example case that shows how the lack of confidence can affect the alternatives ranking and the subsequent decision. Finally, the methodology is applied to a real case study in Colombia to select the best alternative for digestate post-treatment before its application to agricultural soil as a fertilizer. The use of MIMDU presents three major beneficial outcomes for multicriteria decision-making to foster rural development. First, the consideration of the lack of confidence of the respondents can reduce the pressure they might feel when providing an answer without complete knowledge. Second, it allows a more accurate quantification of the opinions given, turning, for example, more hesitant answers into less reliable evaluations of an alternative, that worsens its final ranking. And third, more robust decisions can be taken due to the major precision in the modelling of opinions and the possibility of comparing crisp and fuzzy-based rankings of the alternatives.Dins dels objectius de desenvolupament sostenibles, els serveis energètics moderns es consideren crucials no només per aconseguir l'accés universal a l'energia el 2030, sinó per la seva contribució a pal·liar la pobresa crònica, reduir la inseguretat alimentària, promoure l'accés a la informació moderna a les escoles i permetre l'inici d'activitats productives. Tot i això, l’objectiu d’accés mundial per al 2030 encara està lluny d’acomplir-se, ja que més de 700 milions de persones viuen a les zones rurals sense accés a l’electricitat i utilitzen llenya i altres biomasses tradicionals contaminants per cuinar i escalfar. Els sistemes energètics descentralitzats guanyen pes respecte l’extensió de la xarxa per proporcionar energia a zones rurals i inaccessibles. L’avaluació i el disseny d’aquests sistemes és un procés complex que ha de tenir en compte múltiples alternatives i criteris per garantir una sostenibilitat a llarg termini, però els estudis de literatura disponibles generalment se centren exclusivament en aspectes tècniques i econòmiques. A més, la minoria d’estudis que segueixen un enfocament multicriteri subestimen l’efecte de la manca de confiança potencial dels experts i usuaris consultats per ponderar la importància de cada criteri o avaluar una alternativa específica. En aquest context, l'objectiu d'aquesta tesi és desenvolupar procediments multicriteri considerant la incertesa per afavorir l’obtenció de resultats robustos. Aquests procediments s’apliquen a projectes que afavoreixen l’accés als serveis energètics i promouen, per tant, el desenvolupament de zones rurals i desfavorides. La tesi comença amb dos procediments multicriteri presentats per a l'avaluació i el disseny, respectivament, de projectes d'electrificació rural. Aquests procediments s'apliquen a dos casos pràctics reals al Perú i Nigèria. Ambdues aplicacions proporcionen informació valuosa, per a les autoritats locals i altres promotors de sistemes d’electrificació en contextos similars, sobre quines tecnologies i configuracions a utilitzar en determinades circumstàncies. Al mateix temps, les anàlisis realitzades permeten una millora en quant a la solidesa dels resultats mitjançant la consideració de la manca de confiança de les opinions recollides sobre la importància dels criteris i l’avaluació de les alternatives. Per fer-ho, es desenvolupa una metodologia per a la presa de decisions multicriteri que té en compte la incertesa (MIMDU) basada en nombres difusos per incloure la manca de confiança que els experts i usuaris podrien tenir quan ponderen un criteri o avaluen una alternativa. La metodologia dissenyada inclou un nou procediment per quantificar opinions humanes amb nombres difusos no predefinits i un procés sistemàtic per calcular diversos rànquings d’alternatives i proporcionar informació complementària que condueix a una presa de decisions més robusta. De fet, el potencial de la metodologia s’il·lustra amb un cas d’exemple que mostra com la manca de confiança pot afectar el rànquing d’alternatives i la decisió posterior. Finalment, la metodologia s'aplica a un estudi de cas real a Colòmbia per seleccionar la millor alternativa per al post-tractament del digestat abans de la seva aplicació a sòl agrícola com a fertilitzant. L’ús de MIMDU presenta tres grans beneficis per a la presa de decisions multicriteri per fomentar el desenvolupament rural. En primer lloc, la consideració de la manca de confiança dels enquestats pot reduir la pressió que podrien sentir al donar una resposta sense coneixement complet. En segon lloc, permet una quantificació més precisa de les opinions donades, convertint, per exemple, respostes més dubtoses en avaluacions menys fiables d’una alternativa, que empitjora la seva classificació final. I, en tercer lloc, es poden prendre decisions més robustes a causa de la precisió en la modelització d’opinionsEn 2015, la Organización de las Naciones Unidas definió los Objetivos de Desarrollo Sostenible en una transición hacia un mundo sin pobreza y donde se priorizan los derechos humanos, la equidad y la sostenibilidad. En particular, los servicios energéticos modernos se consideran cruciales no solo para lograr el acceso universal a la energía en 2030, sino por su contribución para aliviar la pobreza crónica, reducir la inseguridad alimentaria, promover el acceso a la información en las escuelas y permitir el inicio de actividades productivas. Sin embargo, el objetivo de acceso global a la energía para 2030 aún está lejos de ser completo, con más de 700 millones de personas viviendo en áreas rurales sin acceso a electricidad y utilizando leña y otra biomasa tradicional contaminante, para cocinar y calentar. Los sistemas de energía descentralizados están ganando peso respecto a la extensión de la red para proporcionar energía a áreas rurales e inaccesibles. La evaluación y el diseño de sistemas descentralizados es un proceso complejo que precisa considerar múltiples alternativas y criterios para que sea sostenible a largo plazo, pero los estudios disponibles en la literatura generalmente se enfocan exclusivamente en aspectos técnicos y económicos. Asimismo, la minoría de estudios que siguen un enfoque de toma de decisiones multicriterio subestiman el efecto de la potencial falta de confianza de los expertos y usuarios consultados para ponderar la importancia de cada criterio o para evaluar una alternativa específica. En este contexto, el objetivo de esta tesis es desarrollar procedimientos multicriterio considerando la incertidumbre para aumentar la robustez de los resultados. Estos procedimientos se aplican a proyectos que fomentan el acceso a los servicios energéticos y, por tanto, promueven el desarrollo de zonas rurales y desfavorecidas. La tesis comienza con dos procedimientos multicriterio presentados para la evaluación y el diseño, respectivamente, de proyectos de electrificación rural. Estos procedimientos se aplican a dos estudios de casos reales en Perú y Nigeria. Ambas aplicaciones pueden proporcionar información valiosa, para las autoridades locales y otros promotores de sistemas de electrificación en contextos similares, sobre qué tecnologías y configuraciones utilizar en determinadas circunstancias. Al mismo tiempo, los análisis realizados permiten una mejora en cuanto a la robustez de los resultados a través de la consideración de la falta de confianza de las opiniones recogidas acerca de la importancia de los criterios y de la evaluación de las alternativas. Para ello, se desarrolla una Metodología para la toma de decisiones multicriterio considerando la incertidumbre (MIMDU) basada en números difusos para incluir la falta de confianza que los expertos y los usuarios pueden tener al ponderar un criterio o evaluar una alternativa La metodología diseñada incluye un procedimiento novedoso para cuantificar opiniones humanas con números difusos no predefinidos y un proceso sistemático para proponer rankings de alternativas y brindar información complementaria que conduce a una toma de decisiones más robusta. El potencial de la metodología se ilustra con un caso de ejemplo que muestra cómo la falta de confianza puede afectar el ranking de alternativas y la decisión posterior. Finalmente, la metodología diseñada se aplica a un estudio de caso real en Colombia para seleccionar la mejor alternativa para el digestato post-tratamiento previo a su aplicación al suelo agrícola como fertilizante. El uso de MIMDU presenta tres importantes beneficios para la toma de decisiones multicriterio en contextos de desarrollo rural. En primer lugar, la consideración de la falta de confianza de los encuestados puede reducir la presión al dar una respuesta sin un conocimiento completo. En segundo lugar, permite una cuantificación más precisa de las opiniones emitidas, convirtiendo, por ejemplo, respuestas más vacilantes en valoraciones menos fiables de una alternativa, que empeora su clasificación final. Y tercero, se pueden tomar decisiones más sólidas debido a la mayor precisión en el modelado de opiniones y la posibilidad de comparar rankings deterministas y difusos de las alternativas.Postprint (published version

Advanced Modeling, Control, and Optimization Methods in Power Hybrid Systems - 2021

The climate changes that are becoming visible today are a challenge for the global research community. In this context, renewable energy sources, fuel cell systems and other energy generating sources must be optimally combined and connected to the grid system using advanced energy transaction methods. As this reprint presents the latest solutions in the implementation of fuel cell and renewable energy in mobile and stationary applications such as hybrid and microgrid power systems based on the Energy Internet, blockchain technology and smart contracts, we hope that they will be of interest to readers working in the related fields mentioned above

Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

In the last decade, distribution systems are experiencing a drastic transformation with the advent of new technologies. In fact, distribution networks are no longer passive systems, considering the current integration rates of new agents such as distributed generation, electrical vehicles and energy storage, which are greatly influencing the way these systems are operated. In addition, the intrinsic DC nature of these components, interfaced to the AC system through power electronics converters, is unlocking the possibility for new distribution topologies based on AC/DC networks. This paper analyzes the evolution of AC distribution systems, the advantages of AC/DC hybrid arrangements and the active role that the new distributed agents may play in the upcoming decarbonized paradigm by providing different ancillary services.Ministerio de Economía y Competitividad ENE2017-84813-RUnión Europea (Programa Horizonte 2020) 76409

Energy storage systems and grid code requirements for large-scale renewables integration in insular grids

This thesis addresses the topic of energy storage systems supporting increased penetration of renewables in insular systems. An overview of energy storage management, forecasting tools and demand side solutions is carried out, comparing the strategic utilization of storage and other competing strategies. Particular emphasis is given to energy storage systems on islands, as a new contribution to earlier studies, addressing their particular requirements, the most appropriate technologies and existing operating projects throughout the world. Several real-world case studies are presented and discussed in detail. Lead-acid battery design parameters are assessed for energy storage applications on insular grids, comparing different battery models. The wind curtailment mitigation effect by means of energy storage resources is also explored. Grid code requirements for large-scale integration of renewables are discussed in an island context, as another new contribution to earlier studies. The current trends on grid code formulation, towards an improved integration of distributed renewable resources in island systems, are addressed. Finally, modeling and control strategies with energy storage systems are addressed. An innovative energy management technique to be used in the day-ahead scheduling of insular systems with Vanadium Redox Flow battery is presented.Esta tese aborda a temática dos sistemas de armazenamento de energia visando o aumento da penetração de energias renováveis em sistemas insulares. Uma visão geral é apresentada acerca da gestão do armazenamento de energia, ferramentas de previsão e soluções do lado da procura de energia, comparando a utilização estratégica do armazenamento e outras estratégias concorrentes. É dada ênfase aos sistemas de armazenamento de energia em ilhas, como uma nova contribuição no estado da arte, abordando as suas necessidades específicas, as tecnologias mais adequadas e os projetos existentes e em funcionamento a nível mundial. Vários casos de estudos reais são apresentados e discutidos em detalhe. Parâmetros de projeto de baterias de chumbo-ácido são avaliados para aplicações de armazenamento de energia em redes insulares, comparando diferentes modelos de baterias. O efeito de redução do potencial de desperdício de energia do vento, recorrendo ao armazenamento de energia, também é perscrutado. As especificidades subjacentes aos códigos de rede para a integração em larga escala de energias renováveis são discutidas em contexto insular, sendo outra nova contribuição no estado da arte. As tendências atuais na elaboração de códigos de rede, no sentido de uma melhor integração da geração distribuída renovável em sistemas insulares, são abordadas. Finalmente, é estudada a modelação e as estratégias de controlo com sistemas de armazenamento de energia. Uma metodologia de gestão de energia inovadora é apresentada para a exploração de curto prazo de sistemas insulares com baterias de fluxo Vanádio Redox

Classification of Wind Turbine Blade Performance State Through Statistical Methods

As wind turbines continue to age, wind farm operators face the challenge of optimizing maintenance scheduling to reduce the associated operation and maintenance (O&M) costs. Wind farm operators typically use conservative maintenance scheduling in order to maximize the uptime of their wind turbines. In most cases however, maintenance may not be necessary and the components could operate for longer before repairs are required. This work presents three papers that collectively focus on providing potentially useful information to aid wind farm operators in making maintenance decisions. In the first paper, the utilization of Geographic Information Systems (GIS) to illustrate data trends across wind farms is introduced to better understand an operation’s signature performance characteristics. It is followed by a paper that presents an improved condition monitoring system for the wind turbine blades through the use of the principal component analysis (PCA). The final paper introduces another condition monitoring system using a k-means clustering algorithm to determine the performance state of wind turbine blades

Review of Optimization Techniques for Sizing Renewable Energy Systems

The growing evidence of the global warning phenomena and the rapid depletion of fossil fuels have drawn the world attention to the exploitation of renewable energy sources (RES). However standalone RES have been proven to be very expensive and unreliable in nature owing to the stochastic nature of the energy sources. Hybrid energy system is an excellent solution for electrification of areas where the grid extension is difficult and not economical. One of the main attribute of hybridising is to be able to optimally size each RES including storages with the aim of minimizing operation costs while efficiently and reliably responding to load demand. Hybrid RES emerges as a trend born out of the need to fully utilize and solve problems associated with the reliability of RES. This paper present a review of techniques used in recent optimal sizing of hybrid RES. It discusses several methodologies and criteria for optimization of hybrid RES. The recent trend in optimization in the field of hybrid RES shows that bio-inspired techniques may provide good optimization of system without extensive long weather data