Contributions of flywheel systems in wind power plants

The stepwise replacement of conventional power plants by renewable-based ones such as wind power plants could a ect the system behaviour and planning. First, the network stability may be compromised as it becomes less resilient against sudden changes in the loads or generator trips. This is because wind turbines are not synchronized with network frequency but they are usually connected to the grid through fast controllable electronic power converters. And second, due to the stochastic nature of wind, the electrical power generated by wind power plants is neither constant non controllable. This aff ects the network planning as the expected generation level depends on non reliable wind forecasts. Also it aff ects the power quality as the fast fluctuations of wind power can cause harmonics and flicker emissions. For these reasons, network operators gradually set up more stringent requirements for the grid integration of wind power. These regulations require wind power plants to behave in several aspects as conventional synchronized generating units. Among other requirements, it is set the provision of some ancillary services to the grid as frequency and voltage control, the capability of withstanding short-circuits and faults, and to respect some threshold level with regard to the quality of the power generated. Accordingly, energy storage systems may play an important role in wind power applications by enhancing the controllability of the output of wind power plants and providing ancillary services to the power system and thus, enabling an increased penetration of wind power in the system. This thesis focuses on the potential uses of flywheel energy storage systems in wind power. The thesis introduces the basis of several energy storage systems as well as identi es their applications in wind power based on an extensive literature review. It follows with the presentation of the design and setting up of a scale-lab flywheel-based energy storage system. From this work, research concentrates on the application of flywheel devices for power smoothing of wind power plants. The developed concepts are proved by simulations but also experimentally using the above mentioned scale-lab test bench. In particular, research focuses on the de nition of an optimization criteria for the operation of flywheel devices while smoothing the wind power, and the design and experimental validation of the proposed control algorithms of the storage device. The last chapters of the thesis research on the role of wind power plants in system frequency control support. In this sense, an extensive literature review on the network operator's requirements for the participation of wind power plants in system frequency control related-tasks is off ered. Also, this review covers the proposed control methods in the literature for enabling wind turbines to participate in system frequency control. The results of this work open the door to the design of control systems of wind turbines and wind power plants for primary frequency control. The contribution of flywheel devices is also considered. Results highlight the tremendous potential of energy storage systems in general for facilitating the grid integration of wind power plants. Regarding the uses of flywheel devices, it is worth noting that some of their characteristics as the high-ramp power rates can be exploited for reducing the variability of the power generated by wind turbines, and thus for improving the quality of the power injected to the grid by wind power plants. Also, they can support wind power plants to ful l the requirements for their participation in system frequency control support related tasks.El progressiu despla cament de plantes de generaci o convencionals per part de plantes de generaci o de tipus renovable, com els parcs e olics, pot afectar el comportament i la plani caci o del sistema el ectric. Primer, l'estabilitat pot ser compromesa ja que el sistema el ectric resulta m es vulnerable davant canvis abruptes provocats per les c arregues del sistema o desconnexions no programades de generadors. Aix o es degut a que les turbines e oliques no estan sincronitzades amb la freqü encia el ectrica del sistema ja que la seva connexi o es a trav es de convertidors electr onics de pot encia. Segon, degut a la gran variabilitat del vent, la pot encia el ectrica generada per les turbines e oliques no es constant ni controlable. En aquest sentit, la qualitat de la pot encia del parc e olic es pot veure compromesa, ja que es poden detectar nivells apreciables d'harm onics i emissions de "flicker" degudes a les r apides variacions de la pot encia generada pel parc e olic. Per aquests motius, els operadors dels sistemes el ectrics fan gradualment m es restrictius els requeriments de connexi o dels parcs e olics al sistema el ectric. Aquestes regulacions requereixen als parcs e olics que es comportin en molts aspectes com plantes de generaci o convencional. Entre d'altres requeriments, els parcs e olics han de proveir serveis auxiliars per a la operaci o del sistema el ectric com tamb e el suport en el control dels nivells de tensi o i freqü encia de la xarxa; oferir suport durant curtcircuits; i mantenir uns nivells m nims en la qualitat de la pot encia generada. Els sistemes d'emmagatzematge d'energia poden millorar la controlabilitat de la pot encia generada pels parcs e olics i ajudar a aquests a proveir serveis auxiliars al sistema el ectric, afavorint aix la seva integraci o a la xarxa. Aquesta tesi tracta l'aplicaci o en parcs e olics dels sistemes d'emmagatzematge d'energia basats en volants d'in ercia. La tesi introdueix les bases de diversos sistemes d'emmagatzematge i identi ca les seves potencials aplicacions en parcs e olics en base a una extensa revisi o bibliogr a ca. El treball continua amb la posta a punt d'un equipament de laboratori, que con gura un sistema d'emmagatzematge d'energia basat en un volant d'in ercia. Següents cap tols de la tesi estudien l'aplicaci o dels volants d'in ercia per a esmorteir el per l fluctuant de la pot encia generada pels parcs e olics. Els treballs es focalitzen en la de nici o dels criteris per a la operaci o optima dels volants d'in ercia per la seva aplicaci o d'esmorteir el per l fluctuant de potencia e olica, i tamb e en el disseny i validaci o experimental dels algoritmes de control desenvolupats per governar el sistema d'emmagatzematge. Els cap tols finals de la tesi tracten sobre el suport al control de freqü encia per part dels parcs e olics. S'ofereix una extensa revisi o bibliografica respecte els requeriments indicats pels operadors del sistema el ectric en aquest sentit. A m es, aquesta revisi o cobreix els m etodes de control dels parcs e olics i turbines e oliques per la seva participaci o en el suport al control de freqü encia. Les conclusions extretes serveixen per proposar sistemes de control de parcs e olics i de turbines e oliques per proveir el servei de control de freqüencia. Aquest treball, tamb e contempla la inclusi o de volants d'in ercia en els parcs e olics. Dels resultats de la tesi se'n dedueix l'important potencial dels sistemes d'emmagatzematge d'energia per a afavorir la integraci o a la xarxa dels parcs e olics. La controlabilitat de la pot encia dels volants d'in ercia, afavoreix el seu us per reduir la variabilitat de la pot encia generada pels parcs e olics, millorant aix la qualitat de pot encia del mateix. A m es, els volants d'in ercia poder ajudar als parcs e olics a complir amb els requeriments per a la seva integraci o a xarxa, com la participaci o en el control de freqüencia del sistema el ectric

Optimization of the operation of smart rural grids through a novel rnergy management system

The paper proposes an innovative Energy Management System (EMS) that optimizes the grid operation based on economic and technical criteria. The EMS inputs the demand and renewable generation forecasts, electricity prices and the status of the distributed storages through the network, and solves with an optimal quarter-hourly dispatch for controllable resources. The performance of the EMS is quantified through diverse proposed metrics. The analyses were based on a real rural grid from the European FP7 project Smart Rural Grid. The performance of the EMS has been evaluated through some scenarios varying the penetration of distributed generation. The obtained results demonstrate that the inclusion of the EMS from both a technical point of view and an economic perspective for the adopted grid is justified. At the technical level, the inclusion of the EMS permits us to significantly increase the power quality in weak and radial networks. At the economic level and from a certain threshold value in renewables’ penetration, the EMS reduces the energy costs for the grid participants, minimizing imports from the external grid and compensating the toll to be paid in the form of the losses incurred by including additional equipment in the network (i.e., distributed storage).Postprint (published version

El acoso en el trabajo : una visión general del Reino Unido

El acoso sexual sepresenta en la actualidad como upa proble^iui laboral que tiene su principal víctima en la im.cjer. En nuestro país son nunicrosos los estudios sobre esta cuestión, por lo que se prefiere aportar una fisión conzpu ceda. Para ello se analiza la regulación existente en el Reino Unido sobre el acoso sexual. El modelo anglosajón requiere que cualquier estudio jurídico se apoye no sólo en la normativa existente sino en las decisiones Judiciales que forman el common law. El artículo se cierra con una visión práctica del acoso puesta de manifesto en los resultados de diversas encuestas._______________________________Nowadays sexual harassment is presented as a working problem in which its main victim is a woman. In this country there are many studies on this issue and thus it is intended to give a comparative point of view. Therefore, it is analyzed the current regulation of sexual harassment in the LTK. It is a requirement of the AngloSaxon model that any juridical study be based not only on the current regulation but also on the judicial decisions (common law). The article concludes by giving a practical view of harassment which is based on the results of different surveys

El diálogo social como vehículo dinamizador en escenarios de crisis económica

El diálogo social constituye un elemento esencial para hacer frente a problemas económicos y sociales. Sin embargo no es una solución exenta de problemas, puesto que en cada momento histórico las relaciones laborales de cada país imponen el camino a seguir. En este artículo se examinan las distintas variantes del diálogo social en España y cómo se orienta para los próximos años a la hora de aportar soluciones a la crisis económica. Además, al analizar este tema, debe aludirse al diálogo social europeo como referencia de actuaciones que luego aterrizarán en los diferentes Estados miembros. Así, se exponen las principales líneas que desde la Unión Europea se pretenden alcanzar.______________________________________The social dialogue as a dynamic vehicle in the face of an economic crisis. However, it is not a solution without consequences because, depending on the historical context, the working relations of each country, guide the path to be followed. In the present article, we examine the different variables of the social dialogue is established in the following years to find solutions for the recession. Moreover, when we analyze this topic, we should refer to the European social dialogue for reference about how to proceed. Eventually, the different members of EU would follow the same reference. In this way, the main goals that the EU wants to achieve are explained

Towards Emotion Recognition: A Persistent Entropy Application

Emotion recognition and classification is a very active area of research. In this paper, we present a first approach to emotion classification using persistent entropy and support vector machines. A topology-based model is applied to obtain a single real number from each raw signal. These data are used as input of a support vector machine to classify signals into 8 different emotions (calm, happy, sad, angry, fearful, disgust and surprised)

Finite metacyclic groups as active sums of cyclic subgroups

The notion of active sum provides an analogue for groups of that of direct sum for abelian groups. One natural question then is which groups are the active sum of cyclic subgroups. Many groups have been found to give a positive answer to this question, while the case of finite metacyclic groups remained unknown. In this note we show that every finite metacyclic group can be recovered as the active sum of a discrete family of cyclic subgroups

El Derecho de sucesiones en los primeros manuales de Derecho español. El caso de la “Ilustración del Derecho real de España” de don Juan Sala Bañuls (II)

Continuación del artículo publicado en el número anterior de este AnuarioEl presente trabajo trata de estudiar cómo era explicado el Derecho de sucesiones en uno de los primeros manuales universitarios, el de don Juan de Sala Ilustración del Derecho Real de España, que será considerado texto oficial en tiempos de Fernando VII. A través de este texto vemos también como todavía seguía en vigor gran parte del Derecho de sucesiones de épocas pasadas, plasmados en dos grandes obras jurídicas: las Partidas y la Novísima Recopilación, esta última a su vez recogía normas de dos importantes Ordenamientos de Cortes, el Ordenamiento de Alcalá y, sobre todo, las Leyes de Toro. Como conclusión, la obra de Sala servirá de modelo a los primeros manuales del siglo XIXThe present work tries to study how the Law of successions was explained in one of the first university manuals, that of don Juan de Sala Ilustración del Derecho Real de España, which will be considered to be an official text in times of Fernando VII. Across this text we see also as still it was following in effect great part of the Law of successions of last epochs, formed of two big juridical works: the Partidas and the Novísima Recopilación, the latter in turn was gathering procedure of two important Ordenamientos de Cortes, the Ordenamiento de Alcalá and, especially, the Leyes de Toro. As conclusion, the work of Sala will use as model to the first manuals of the 19th\ud centuryIV. EL CONTENIDO DEL TESTAMENTO. 1. Legítima y mejoras. 2. Los legados: 2.1. Concepto. 2.2. Contenido del legado. 2.3. Extinción del legado. 2.4. Límite de la cuantía del legado. La “cuarta falcidia”. 3. Los fideicomisos. 4. Las donaciones “mortis causa”. V. LOS MAYORAZGOS. 1. Concepto. 2. Formación del mayorazgo. 3. Tipos de mayorazgos. 4. Reglas de los mayorazgos regulares. VI. LA SUCESIÓN INTESTADA. 1. Concepto. 2. Los órdenes de sucesión: 2.1. Descendientes. 2.2. Ascendientes. 2.3. Parientes colaterales. 3. Adjudicación de los bienes. 4. Bienes sujetos a reserva. VII. CONCLUSIONE

Análisis de la organización funcional en el fútbol

De manera tradicional, el estudio de la estrategia motriz (táctica) en el fútbol se ha venido realizando tomando como referencia de partida, la distribución espacial de los jugadores al inicio de cada parte de los encuentros y las denominadas "jugadas estratégicas" o "jugadas a balón parado". Este trabajo es una investigación sobre la estrategia motriz en el fútbol, la cual tiene como referente teórico a la Praxiología motriz. Sus objetivos son el estudio de la estrategia motriz (táctica), específicamente la organización funcional: usos de los subroles estratégico motores, de los equipos, en tanto que interacción motriz; considerando también las acciones con balón y su gestió

Smart grid architecture for rural distribution networks: application to a Spanish pilot network

This paper presents a novel architecture for rural distribution grids. This architecture is designed to modernize traditional rural networks into new Smart Grid ones. The architecture tackles innovation actions on both the power plane and the management plane of the system. In the power plane, the architecture focuses on exploiting the synergies between telecommunications and innovative technologies based on power electronics managing low scale electrical storage. In the management plane, a decentralized management system is proposed based on the addition of two new agents assisting the typical Supervisory Control And Data Acquisition (SCADA) system of distribution system operators. Altogether, the proposed architecture enables operators to use more effectively—in an automated and decentralized way—weak rural distribution systems, increasing the capability to integrate new distributed energy resources. This architecture is being implemented in a real Pilot Network located in Spain, in the frame of the European Smart Rural Grid project. The paper also includes a study case showing one of the potentialities of one of the principal technologies developed in the project and underpinning the realization of the new architecture: the so-called Intelligent Distribution Power Router.Postprint (published version