PV Hosting Capacity Analysis and Enhancement Using High Resolution Stochastic Modeling

Reduction of CO2 emissions is a main target in the future smart grid. This goal is boosting the installation of renewable energy resources (RES), as well as a major consumer engagement that seeks for a more efficient utilization of these resources toward the figure of ‘prosumers’. Nevertheless, these resources present an intermittent nature, which requires the presence of an energy storage system and an energy management system (EMS) to ensure an uninterrupted power supply. Moreover, network-related issues might arise due to the increasing power of renewable resources installed in the grid, the storage systems also being capable of contributing to the network stability. However, to assess these future scenarios and test the control strategies, a simulation system is needed. The aim of this paper is to analyze the interaction between residential consumers with high penetration of PV generation and distributed storage and the grid by means of a high temporal resolution simulation scenario based on a stochastic residential load model and PV production records. Results of the model are presented for different PV power rates and storage capacities, as well as a two-level charging strategy as a mechanism for increasing the hosting capacity (HC) of the network

Técnicas avanzadas de Protección de Redes Eléctricas Inteligentes

Existen diferentes ideas sobre lo que es una Smart Grid o red inteligente y así, mientras que unos la definen como un sistema basado en redes locales cuasi autónomas, otros se plantean una red de este tipo como una entrega de electricidad desde la parte de generación hasta el consumidor usando la tecnología digital para ahorrar energía, reducir costos e incrementar la fiabilidad. Básicamente, el objetivo de Smart Grid es aumentar la eficiencia en los sistemas de generación, transmisión y distribución de las empresas eléctricas. Smart Grid es sinónimo de: innovación en sistemas eléctricos, generación distribuida (Distributed Generation, DG), aprovechamiento de recursos renovables, una solución a problemas ambientales, mayor acercamiento a diversas zonas geográficas y demográficas y mejoras en el control de carga. Con la presente tesis, se ha pretendido plasmar un estado del arte actual, en lo que al estudio de calidad de suministro se refiere. La propia elaboración del documento ha permitido un sondeo de los nichos de investigación que podrían ser interesantes respecto al tema. Esta tesis aborda la detección rápida de perturbaciones de señales eléctricas para integrar esta funcionalidad avanzada en inversores inteligentes, dentro del marco de la integración en la red, a gran escala, de fuentes de energía renovables. Se propone una técnica basada en estadística, actuando en el paradigma de detección de faltas y aislamiento (Fault Detection and Isolation, FDI), para la detección temprana en el sistema de potencia. Con ello se pretende mejorar la actuación sobre los sistemas de interconexión y la eficiencia energética de la red eléctrica. El nuevo método está basado en suma acumulativa (CUmulative SUM, CUSUM) y es aplicado a un amplio conjunto de eventos de calidad de suministro para analizar su rendimiento. Los resultados obtenidos indican que el algoritmo propuesto genera residuos robustos y estima con gran precisión las transiciones de los eventos analizados. La principal ventaja del método es que permite una detección de eventos más rápida que los métodos tradicionales, debido a que realiza un procesamiento de muestra a muestra. Además, el método propuesto no requiere demasiado esfuerzo computacional, lo que significa que es adecuado para la integración de un relé de protección multifuncional disponible en los nuevos inversores inteligentes. Se presenta también el diseño y desarrollo de una arquitectura flexible, robusta, modular y con la potencia de cálculo adecuada para la implementación de estos nuevos sistemas de protección y medida para la eficiencia energética. Finalmente, se presenta el rendimiento de un método de segmentación causal y anti-causal (CaC) para la localización automática de las partes no estacionarias de eventos de calidad de suministro. La localización exacta en el tiempo de eventos y la consecuencia de los mismos es importante para analizar de forma automática las perturbaciones en la Smart Grid del futuro. El método de segmentación desarrollado también se basa en el algoritmo CUSUM. La principal ventaja de la segmentación CaC es la elevada precisión en la localización de los segmentos de transición.There are different ideas about what a Smart Grid is. On the one hand, some authors define it as a system based on local electrical networks, which are almost autonomous. On the other hand, others visualize it as a kind of network where the electricity is delivered from the utilities to consumers using digital technology to save energy, reduce costs and increase the reliability of the system. Basically, the goal of Smart Grid is to increase efficiency in generation, transmission and distribution systems from power companies of the electric business. Thus, Smart Grid covers concept such as innovation in electrical systems, Distributed Generation (DG), the use of renewable resources, a solution to environmental problems, the integration of geographic and demographic areas and improvements in the load control. The aim of this thesis was to obtain a true global perspective of the components that comprise the system, and future trends that seem interesting under the development that is expected from DG in particular in the coming years. Therefore, the production of the document itself has enabled a survey of the research niches that could be interesting on the field of study. This thesis addresses the fast detection of electrical signal disturbances for advanced smart inverter functionalities within the framework of large-scale grid integration of renewable energy sources. A statistical-based technique under the fault detection and isolation (FDI) paradigm is proposed for fast events detection in power systems. The aim is to improve the performance of interconnection systems and the energy efficiency of the electricity grid. The method developed is based on the CUmulative SUM (CUSUM) algorithm and is applied to a wide range of power quality events to analyze its performance. The results show that the method generates residuals that are robust to noise and accurately estimates the time locations of underlying transitions in the power system. The main advantage of the proposed technique is its earlier event detection, with respect to other traditional methods, since it performs sample-by-sample evaluations. Moreover, the proposed technique does not require much computational effort, which means that the presented detection method is suitable for integration into the multifunction relay protection subsystems available in novel smart inverters. The design and development of a flexible, robust and modular architecture are presented; it integrates adequate computing power to implement these new protection systems and energy efficiency. Finally, the performance of a joint causal and anti-causal (CaC) segmentation method for automatic location of nonstationary parts of power quality events is presented. The accurate time allocation of events and sequences of events is important to automatically analyze disturbances in the future Smart Grid. The segmentation method developed is also based on the CUSUM algorithm. The main advantage of CaC segmentation is the high precision in the location of the transition segments

Islamic finance : developments and outlook

Artículo de revist

A escena contra el ejercicio de poder a través del cuerpo: el pelo en la búsqueda de la libertad.

This article explores the complex relationship between the body, identity, and territory, focusing on how social and cultural pressures exert control over the body, specifically through the lens of hair and its symbolic power. Using a dialogue format, the authors reflect on their personal experiences with societal expectations regarding appearance and discuss how these seemingly minor decisions are deeply influenced by broader structures of power and control. The body is presented not only as a physical entity but also as a symbolic and cultural space where norms, gender, and power dynamics intersect. The text further analyzes how capitalism and contemporary digital spaces reinforce these mechanisms, while also highlighting the importance of resistance and personal autonomy in constructing identity.El artículo aborda la relación entre el cuerpo, la identidad y el territorio, centrándose en cómo el control sobre aspectos corporales aparentemente triviales, como el cabello, puede convertirse en un mecanismo de poder. A través del diálogo entre les autores, se exploran experiencias personales sobre la presión social relacionada con el cuerpo y el territorio, cuestionando las normas impuestas desde el contexto social y cultural. Se reflexiona sobre la manera en que el cuerpo, más allá de ser una entidad física, se convierte en una construcción simbólica y cultural donde se inscriben significados sociales, de género y de poder. Asimismo, se destaca cómo estas dinámicas son utilizadas por estructuras de poder y capitalismo para moldear y controlar a los individuos

Desarrollo de equipos electrónicos para su uso docente en materias tecnológicas: un caso práctico

El coste de algunos equipos electrónicos que se emplean en la docencia práctica de materias de tipo tecnológico impide en ocasiones la dotación completa de los laboratorios. Se plantea en este artículo un caso práctico de diseño y construcción de un prototipo de equipo electrónico para su uso en prácticas de asignaturas en las cuales se precise experimentar con la utilización de variadores electrónicos de velocidad. Los resultados obtenidos permiten asegurar que para determinados casos es posible desarrollar equipos de carácter didáctico que realizan funciones similares a los dispositivos industriales, a un coste sensiblemente inferior, obviando, por supuesto, el coste de desarrollo

An association rule mining method for estimating the impact of project management policies on software quality, development time and effort

Accurate and early estimations are essential for effective decision making in software project management. Nowadays, classical estimation models are being replaced by data mining models due to their application simplicity and the rapid production of profitable results. In this work, a method for mining association rules that relate project attributes is proposed. It deals with the problem of discretizing continuous data in order to generate a manageable number of high confident association rules. The method was validated by applying it to data from a Software Project Simulator. The association model obtained allows us to estimate the influence of certain management policy factors on various software project attributes simultaneously

Balancing software engineering education and industrial needs

In the world of information and communications technologies the demand for professionals with software engineering skills grows at an exponential rate. On this ground, we have conducted a study to help both academia and the software industry form a picture of the relationship between the competences of recent graduates of undergraduate and graduate software engineering programmes and the tasks that these professionals are to perform as part of their jobs in industry. Thanks to this study, academia will be able to observe which skills demanded by industry the software engineering curricula do or do not cater for, and industry will be able to ascertain which tasks a recent software engineering programme graduate is well qualified to perform. The study focuses on the software engineering knowledge guidelines provided in SE2004 and GSwE2009, and the job profiles identified by Career Space

Proposal of a new indicator to define ductility applied to corroded steel reinforcement on concrete structures = Propuesta de un nuevo indicador para definir la ductilidad aplicada a la corrosión del acero de refuerzo en estructuras de hormigón

The carbonation of concrete or the chlorides ingress in such quantity to reach the level of bars is triggers of reinforcement corrosion. One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Reinforcement ductility has a decisive effect on the overall ductility of reinforced concrete structures. Different Codes classify the type of steel depending on their ductility defined by the minimum values of several parameters. Using indicators of ductility associating different properties can be advantageous on many occasions. It is considered necessary to define the ductility by means of a single parameter that considers strength values and deformation simultaneously. There are a number of criteria for defining steel ductility by a single parameter. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when exposed to accelerated corrosion. This paper analyzes the suitability of a new indicator of ductility used in corroded bars