Power systems with high renewable energy sources: A review of inertia and frequency control strategies over time

Traditionally, inertia in power systems has been determined by considering all the rotating masses directly connected to the grid. During the last decade, the integration of renewable energy sources, mainly photovoltaic installations and wind power plants, has led to a significant dynamic characteristic change in power systems. This change is mainly due to the fact that most renewables have power electronics at the grid interface. The overall impact on stability and reliability analysis of power systems is very significant. The power systems become more dynamic and require a new set of strategies modifying traditional generation control algorithms. Indeed, renewable generation units are decoupled from the grid by electronic converters, decreasing the overall inertia of the grid. ‘Hidden inertia’, ‘synthetic inertia’ or ‘virtual inertia’ are terms currently used to represent artificial inertia created by converter control of the renewable sources. Alternative spinning reserves are then needed in the new power system with high penetration renewables, where the lack of rotating masses directly connected to the grid must be emulated to maintain an acceptable power system reliability. This paper reviews the inertia concept in terms of values and their evolution in the last decades, as well as the damping factor values. A comparison of the rotational grid inertia for traditional and current averaged generation mix scenarios is also carried out. In addition, an extensive discussion on wind and photovoltaic power plants and their contributions to inertia in terms of frequency control strategies is included in the paper.This work was supported by the Spanish Education, Culture and Sports Ministry [FPU16/04282]

Influencia del tratamiento termico sobre las propiedades mecánicas de fibras acrílicas retractiles.

Tres fibras acrilicas de tipo retrdctil de 2'9, 4'7 y 10 dtex fueron sometidas a tratamientos termicos con aire caliente a distintas temperaturas y distintos tiempos de acción. Se han comparado sus características físico-mecánicas con las de otras fibras tratadas por el procedimiento clásico de vapor. Se han establecido condiciones 6ptimas de tratamiento, considerando las mejoras obtenidas.Three acrylic retractile fibres of 2'9, 4'7 and 10 dtex were subjected to heat treatments by hot air at different temperatures and treatment times. Their physico-mechanical caracteristics are compared with those of fibres treated by stearn. Optimum test conditions are established taking into consideration improvernents achieved.Trois fibres acryliques de type retractil de 2'9,4'7 et 10 dtex, on été soumisses à des traitements thermiques a l'air chaud, A differentes temperatures et à differents temps d'action. On a cornparé leurs caractéristiques physico-mécaniques avec celles des autres fibres quiont été traitées par la méthode clasique de la vapeur. On a établi les conditions optimum des traitements, tenant compte des améliorations obténues.Peer Reviewe

Reconstrucción de fondo de escena basada en la mediana

En este TFG se aborda la tarea de reconstrucción o inicialización de fondo centrándose en el análisis del funcionamiento del algoritmo LabGen-P y en algunas variantes propuestas del mismo. Este algoritmo se basa en reconstruir el fondo usando la mediana temporal de los pixels con menos movimiento. La selección de dicho algoritmo se debe a sus buenos resultados en la reciente competición sobre inicialización de fondo1. Inicialmente, se estudiará el estado del arte para comprender los distintos retos que plantean la tarea de inicialización de fondo y qué estrategias se han utilizado en la literatura para abordarlos.Después se procederá a la implementación del algoritmo LabGen-P,cuyos resultados son de una alta calidad,con el objetivo de comprender su funcionamiento, bondades y deficiencias. A continuación, se introducirán modificaciones encaminadas a solventar dichas deficiencias, entre las que están la estimación de movimiento empleada y la inclusión de una nueva información espacial basada en el tamaño de las regiones. Finalmente, se evaluará el rendimiento del algoritmo base y cada una de las modificaciones introducidas en él, con la finalidad de analizar sus funcionamientos y determinar cuál es el mejor de ellos.In this Bachelor´s thesis we have tackled the task of reconstructing or initializing a background image using the LabGen-P algorithm and some proposed variants. This algorithm reconstructs the background using the temporal median of the pixels with less motion in time. This algorithm has beeen selected due to the good results obtained in a recent background initialization competition2. Initially, we will study the state-of-the-art to fully understand the different challenges that background initialization poses and the techniques used in the literature to addressed them. Subsequently, we will implement the LabGen-P algorithm, which has high quality results, in order to understand its strengths and weaknesses. Then, we will introduce variations in the algorithm to deal with its issues. Among these variations we can find the use of an improved motion estimation and the inclusion of spatial information based on segmented image regions sizes. Finally, we will evaluate the base algorithm and the proposed variations to determine the best configuratio

Design, development and evaluation of a software architecture for tracking multiple vehicles in camera networks

Máster en Image Processing and Computer VisionThe free-flow portico is an automatic toll system that works thanks to the information provided by different system cameras and the use of new technologies. This work is focused on an essential part for the creation of this infrastructure, the development of the software needed to detect, classify and track targets across a network of cameras, known as multi-target multi-camera tracking, as well as the study of the hardware necessary for its deployment. First of all is to study the state of the art to understand the different methods that exist for the development of each of the tasks of this system. Afterwards, the proposal made for the selected design will be studied. This design will be formed by three cameras placed on the portico, which will be connected to a board of image processing and a strobe to provide the necessary lighting at night time. In addition to these systems it will be necessary to use a central system that will carry out the tasks of communication between the three cameras, in order to have a compact design that stores the information of each vehicle that goes through the portico. This information will contain the type of registration vehicle and the type of axles that it used. Later, the study of the hardware systems that will be used for the composition of this multicamera system will be carried out, and some of the most prominent software sections. An experimental system will be proposed for the analysis of the overall results of the system, as well as the comparison between the different proposed algorithms, in order to analyze its operations and determine which one of them is the best. This work is part of a real project that is currently being developed in INDRA, for the implementation in Spanish and international highways

An interface between an hp-adaptive finite element package and the pre- and post-processor GiD

An interface between GiD, the interactive graphical user interface used for numerical simulations, developed at the International Center for Numerical Methods in Engineering (CIMNE) of the Universidad Politécnica de Cataluña and the Geometrical Modeling Package (GMP) of the fully automatic hp-adaptive finite element (FE) software, developed at the Institute for Computational Engineering and Sciences (ICES) of the University of Texas at Austin, is presented. GiD is used to construct a tessellation of the problem domain into FE-like regions (blocks in GMP terminology), and the interface obtains and transfers all the topological and geometrical information to GMP. Then, GMP automatically constructs a parameterization for each FE-like region of the GMP mesh, which later can be used to generate the actual FE-mesh and support geometry updates during mesh refinements

Método de Elementos Finitos hp con Adaptabilidad Automática Orientada a un Objetivo para Problemas Abiertos en 2D

In this paper, we describe a fully automatic goaloriented hp-adaptive Finite Element strategy, which is applied to open problems (radiation and scattering). The methodology produces exponential convergence rates in terms of an upper bound of an user-prescribed quantity of interest (in our case, the S-parameter, the far radiated field or far scattering field) against the problem size (number of degrees of freedom). We illustrate the efficiency of the method with 2D numerical simulations of open problems (radiation and scattering). Applications include the far scattering (radiated) field by an object (antenna) and the computation of mutual coupling of the antennas (S-parameters). Results show that self-adaptive goal-oriented hp obtains more accuracy in the quantity of interest than self-adaptive energynorm hp with the same number of degrees of freedom

Los caprélidos (Crustacea: Amphipoda) del estrecho de Gibraltar y su utilidad como bioindicadores marinos

Los caprélidos son pequeños crustáceos marinos que viven asociados a algas e invertebrados marinos principalmente. Aunque son fundamentales en las redes tróficas marinas y sirven de alimento a muchas especies de peces, han sido muy poco estudiados. El laboratorio de Biología Marina ha desarrollado en los últimos años un estudio exhaustivo de las comunidades de caprélidos del Campo de Gibraltar. Se han descrito 10 especies nuevas para la ciencia y seis nuevas citas para el estrecho de Gibraltar ascendiendo hasta 28 el número de especies conocidas para el Campo de Gibraltar. La mayoría de las especies de caprélidos se han encontrado sobre algas e hidrozoos, aunque algunos se han encontrado asociados al sedimento. En cuanto al modo de alimentación, existen especies filtradoras, depredadoras y depositívoras y se concluye que la estrategia alimentaria está claramente relacionada con el comportamiento de sujección al sustrato (posición erguida versus paralela). Se ha observado canibalismo en la especie Phtisica marina y cuidado parental de los juveniles en Pseudoprotella phasma . Al carecer de fase larvaria planctónica, los caprélidos tienen limitada la capacidad de dispersión. Se ha demostrado también el valor de los caprélidos como bioindicadores; estudiando la comunidad de caprélidos puede conocerse, sin necesidad de realizar costosos análisis fisicoquímicos, la calidad ambiental de las zonas costeras

TEmporal Scale SIgmoid Curve (TESIC): A tool to characterize short-term demand variability at water supply systems

[EN] Water demand is the main random factor that conditions flow variability across water supply systems. Water demand measurements or pseudomeasurements (i.e. estimations based on historical data) are associated with a time interval (sampling rate), which affects the variability of water demands. Considering a long time interval implies losing information about water consumption within that temporal window. The variance (i.e. quantification of variability) computed from demand records is thus only “apparent”, because the variability within the time interval is averaged and lost (i.e. “missed”). The relationship between missed and apparent variability can be assessed through the so-called TEmporal scale SIgmoid Curve (TESIC), which is here presented as a tool to characterize short-term demand variability. TESIC is used in this work to compute demand uncertainty for a given time resolution level and to estimate peak demands for different temporal resolutions in a realistic water supply case study. These applications show that TESIC provides a conceptual framework to explain and quantify the temporal resolution effect in hydraulic modelling applications.The authors would like to thank the financial support provided by the Spanish Ministry of Science and Innovation - State Research Agency (Grant PID2019-111506RB-I00 funded by MCIN/AEI/10.13039/ 501100011033) and Junta de Comunidades de Castilla-La Mancha (Grant SBPLY/19/180501/000162 funded by Junta de Comunidades de Castilla-La Mancha and ERDF A way of making Europe).Ruiz Gómez, E.; Díaz García, S.; González Pérez, J. (2024). TEmporal Scale SIgmoid Curve (TESIC): A tool to characterize short-term demand variability at water supply systems. Editorial Universitat Politècnica de València. https://doi.org/10.4995/WDSA-CCWI2022.2022.1414