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  • Experimental Validation of Optimal Real-time Energy Management System for Microgrids.

     Marzband, Mousa
    Defense's date: 2014-01-20
    Universitat Politècnica de Catalunya
    Theses

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    Actualmente, producción, la fiabilidad, calidad de la energía, la eficiencia y la penetración de las energías renovables son algunos de los temas más importantes en el análisis de sistemas de potencia. Por este motivo, la necesidad de obtener una potencia óptima y las políticas de despacho económicos se requieren al mismo tiempo. Un gran interés para la extracción de un rendimiento minimizando precio óptimo del mercado de compensación (MCP) para los consumidores y el mejor uso de las fuentes renovables de energía está en aumento en los últimos años. A causa de balance de energía entre las fluctuaciones en la demanda de carga y de carácter no gestionable por fuentes renovables, para implementar un sistema de gestión de energía (EMS) tiene gran interés dentro Microgrid (MG). La aparición de nuevas tecnologías como el almacenamiento de energía (ES) ha provocado un aumento en el esfuerzo para presentar métodos nuevos o modificados de optimización de la gestión del sistema eléctrico. La predicción de las fuentes de energía renovables sólo puede predecirse con precisión con una pequeña anticipación. Por lo tanto, para aumentar la eficiencia del algoritmo de optimización presentado a gran escala, nuevos métodos deben ser propuestos en esta dirección, en especial en la programación a corto plazo. Se necesitan métodos de optimización de gran alcance para ser aplicado y lograr el máximo rendimiento, aumentar el despacho económico, así como la adquisición de las mejores prestaciones de estos sistemas. De acuerdo con los casos antes mencionados, la gestión de energía en tiempo real dentro de MG es un agente necesario para los operadores para garantizar un funcionamiento óptimo y seguro del sistema. La propuesta EMS debería ser capaz de programar la generación MG con la información mínima compartido enviado por unidades de generación. Para llegar a esta capacidad, esta tesis presenta una arquitectura operacional para la operación en tiempo real (RTO) de una MG que opera en ambos modos en isla y conectados a la red. La arquitectura presentada es flexible y se podría utilizar para diferentes configuraciones de MG también en diferentes escenarios. Una fórmula general se presenta también para la estimación de la estrategia de funcionamiento óptimo, plan de optimización de costes y la reducción de la electricidad consumida combinado con respuesta de la demanda (DR). El problema propuesto se formula en combinación como un problema de optimización con restricciones no lineales para reducir al mínimo el costo relacionado con las fuentes de generación y la carga de respuesta, así como la reducción de MCP. Se formula como un problema de optimización no lineal que tiene la igualdad y limitaciones no igualdad. Varios métodos de optimización como la programación lineal mixta, fuente de pivote, la competencia imperialista, colmena artificial, enjambre de partículas, colonia de hormigas, algoritmos de búsqueda gravitacionales son utilizados para lograr objetivos específicos. El objetivo principal de esta tesis es el de validar experimentalmente el diseño de un sistema de gestión de energía en tiempo real para los MGs en ambos modos de funcionamiento adecuado para diferentes tamaños y tipos de recursos de generación y dispositivos de almacenamiento con estructura de plug- and-play. Como resultado, este sistema es capaz de adaptarse a los cambios en la generación y activos de almacenamiento, en tiempo real, y la entrega de órdenes de operación óptimas para los activos de forma rápida, el uso de un mercado local de energía (LEM) estructura basada en una sola cara o de doble cara subasta. El estudio está dirigido a exponer la operación óptima de micro- fuentes a, así como para disminuir el costo de producción de electricidad por día y por hora en tiempo real por delante de programación. Validación de resultados experimentales muestran la eficacia para un funcionamiento óptimo con el mínimo coste y capacidad plug- and-play en un MG.

  • Design, operation and control of novel electrical concepts for offshore wind power plants

     Prada Gil, Mikel De
    Defense's date: 2014-06-13
    Universitat Politècnica de Catalunya
    Theses

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    La energía eólica marina es un sector emergente que se encuentra en plena expansión. Cada vez existen más parques eólicos marinos, tanto en Europa como en el resto del mundo, principalmente debido a que en el mar el viento sopla con más intensidad y de una manera más constante que en tierra, lo cual posibilita obtener una mayor generación de energía eólica. Además, el hecho de que los parques eólicos marinos no padezcan tantas limitaciones de espacio permite poder instalar turbinas de mayor potencia y tamaño. Hoy en día, factores medioambientales y sociales están obligando a construir los parques eólicos marinos cada vez más alejados de la costa y se espera que esta tendencia continúe en los próximos años. Varios estudios han demostrado que a partir de una cierta distancia crítica entre el parque eólico y su punto de conexión a tierra (aproximadamente 55-70 km), la transmisión mediante alta tensión en corriente continua (ATCC) resulta una opción más interesante que a través de una transmisión en alta tensión de corriente alterna (ATCA), ya que las pérdidas en los cables se ven reducidas, así como los requerimientos de potencia reactiva. Esta tendencia hacia construir parques eólicos marinos cada vez mayores y a ubicarlos más alejados de la costa, supone el tener que resolver cierto retos técnicos, económicos y políticos a fin de poder ser más competitivos en el futuro en comparación con otras fuentes de generación de energía. Hoy en día, existe una importante preocupación por tratar de reducir el elevado coste actual de la energía para los proyectos de eólica marina a base de mejorar la fiabilidad y disponibilidad del sistema, reducir costes de operación y mantenimiento y/o incrementar la generación de energía.Esta tesis tiene como objetivo proponer conceptos eléctricos novedosos, aplicados a parques eólicos marinos, que resulten más rentables que los existentes actualmente. Asimismo, esta tesis pretende analizar la factibilidad, tanto técnica como económica, de dichos conceptos. Asuntos tales como el diseño, la optimización, el modelaje, la operación y el control son presentes en la tesis. El alcance del trabajo se focaliza en la red interna de un parque eólico y no se analiza, el sistema de transmisión ni su integración a la red. El primer concepto de parque eólico evaluado puede ser aplicado tanto en parques situados en tierra como en el mar, que tengan una red interna de CA en media tensión (MTCA) y un sistema de transmisión tanto ATCC o ATCA. Respecto al resto de configuraciones presentadas, éstas vienen motivadas por la presencia de la tecnología ATCC y su capacidad para desacoplar eléctricamente la red interna del parque eólico del sistema eléctrico de potencia situado en tierra. Así pues, la primera propuesta a analizar consiste en operar algunas máquinas concretas por debajo de su punto óptimo de operación a fin de poder reducir el efecto estela dentro del parque y poder así maximizar la potencia total extraída por el mismo. Los tres siguientes diseños de parque se fundamentan en la posibilidad que ofrece la tecnología ATCC de poder operar la red interna del parque a una frecuencia variable. Así pues, se propone estudiar la posibilidad de considerar parques eólicos donde se eliminan o se reducen los convertidores de cada turbina gracias a disponer del convertidor central situado en la subestación marina, el cual ejerce un control centralizado a todo el parque. Finalmente, el último concepto presentado en esta tesis analiza la posibilidad de considerar un parque eólico marino completamente en CC (transmisión y red interna del parque), a fin de poder reducir las pérdidas tanto en la red interna como en el cable de exportación.En términos generales se concluye que todos los conceptos propuestos a lo largo de esta tesis sugieren un gran potencial para poder ser aplicados en futuros parques eólicos marinos, ya que su coste de energía se ve reducido en comparación con los parques eólicos existentes hoy en día.

  • Probabilistic analysis to assess the impact of the charge of electric vehicles on distribution grids under normal operation  Open access

     Valsera Naranjo, Eduardo
    Defense's date: 2014-05-07
    Universitat Politècnica de Catalunya
    Theses

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    La incorporación de altos niveles a generación distribuida no despachable a pequeña escala está causando la transición de los tradicionales sistemas eléctricos de potencia 'verticales' a los sistemas de potencia 'operados horizontalmente', en donde dichas redes de distribución pueden contener tanto generación como consumos de carácter estocástico (p. ej. La recarga de vehículos eléctricos). Este hecho incrementa el número de variables estocásticas y las dependencias entre estas de forma considerable. Los análisis determinísticos no son suficientes para lidiar con estos nuevos factores y se necesita enfocar el problema de otro modo. Los análisis probabilísticos proporcionan una mejor manera de abordar la situación.Esta tesis describe el impacto de la recarga de vehículos eléctricos (para los cuales se ha usado un modelo detallado para las curvas de carga y descarga de sus baterías) en la red eléctrica. El método probabilístico Monte Carlo se ha aplicado a una red de equiparable a una red distribución española donde también se han considerado patrones de movilidad de vehículos (en este caso de la ciudad de Barcelona). Para llevar a cabo los análisis, en primer lugar se ha adaptado una red de estudio de IEEE con los parámetros de la red de distribución española. A continuación se ha modelado el comportamiento de las baterías de los vehículos eléctricos a partir de las características de baterías de modelos reales de vehículos eléctricos que ya están en el mercado. Finalmente, se han considerado diferentes estrategias de control en el momento de realizar la recarga de vehículos eléctricos.A partir de los datos obtenidos se han generado modelos estadísticos tanto para los consumos domésticos de la red como para la recarga de los vehículos eléctricos. Con dichos modelos se ha llevado a cabo un análisis Monte Carlo para estudiar los niveles de carga tanto de líneas como de transformadores. Los resultados obtenidos demuestran la importancia del correcto modelado de las baterías ya que se aumenta la precisión de los análisis. Adicionalmente, los patrones de movilidad de la zona a estudiar han demostrado ser clave en este tipo de estudio.

    The incorporation of high levels of small-scale non-dispatchable distributed generation is leading to the transition from the traditional 'vertical' power system structure to a 'horizontally-operated' power system, where the distribution networks contain both stochastic generation and load (such as electric vehicles recharging). This fact increases the number of stochastic inputs and dependence structures between them need to be considered. The deterministic analysis is not enough to cope with these issues and a new approach is needed. Probabilistic analysis provides a better approach. This PhD thesis describes the grid impact analysis of charging electric vehicles (EV) using charging curves with detailed battery modelling. A probabilistic method using Monte Carlo was applied to a typical Spanish distribution grid, also using mobility patterns of Barcelona. To carry out this analysis, firstly, an IEEE test system was adapted to a typical distribution grid configuration; secondly, the EV and its battery types were modeled taking into account the current vehicle market and the battery characteristics; and, finally, the recharge control strategies were taken in account. Once these main features were established, a statistical probabilistic model for the household electrical demand and for the EV charging parameters was determined. With these probabilistic models, the Monte Carlo analysis was performed within the established scenario in order to study the lines' and the transformers' loading levels. The results show that an accurate model for the battery gives a more precise estimation about the impact on the grid. Additionally, mobility patterns have been proved to be some of the most important key aspects for these type of studies.

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  • Control of a flywheel energy storage system for power smoothing in wind power plants

     Díaz González, Francisco; Bianchi, Fernando Daniel; Sumper, Andreas; Gomis Bellmunt, Oriol
    IEEE transactions on energy conversion
    Date of publication: 2014-03-01
    Journal article

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    This paper deals with the design and the experimental validation in scale-lab test benches of an energy management algorithm based on feedback control techniques for a flywheel energy storage device. The aim of the flywheel is to smooth the net power injected to the grid by a wind turbine or by a wind power plant. In particular, the objective is to compensate the power disturbances produced by the cycling torque disturbances of the wind turbines due to the airflow deviation through its tower section. This paper describes the control design, its tuning, as well as the description of the experimental setup, and the methods for the experimental validation of the proposed concepts. Results show that the fast wind power fluctuations can be mostly compensated through the flywheel support.

  • Flicker mitigation by reactive power control in wind farm with doubly fed induction generators

     Girbau Llistuella, Francesc; Sumper, Andreas; Díaz González, Francisco; Galceran Arellano, Samuel
    International journal of electrical power and energy systems
    Date of publication: 2014-02
    Journal article

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    This paper presents a novel wind farm control with the purpose to mitigate the flicker emission of doubly fed induction generators. The presented control strategy is implemented in a wind farm connected to a distribution grid with consumers. The control system is composed by two controllers in cascade, the wind farm control and the local wind turbine controller. The wind farm control adapts itself to the consumptions of the distribution network and generates the minimal reactive power which allows smoothing the fast variations of wind power output. In this sense, the wind farm control facilitates the integration of wind farm into weak power grids by exchanging reactive power with network. Moreover, the wind farm controller has to be stable, fast and robust and the wind farm dispatch function has to guarantees that the local wind turbine controller can exchange the reactive power set point with network. This controller has been developed with the simulation tool DigSilent PowerFactory v14.1. © 2013 Elsevier Ltd. All rights reserved.

  • Active power estimation of photovoltaic generators for distribution network planning based on correlation models

     Ramón Marín, Miquel; Sumper, Andreas; Villafafila Robles, Roberto; Bergas Jane, Joan Gabriel
    03605442
    Date of publication: 2014-01-01
    Journal article

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    For the last years, PV (photovoltaic) generation has been having an important impact on LV (low voltage) and MV (medium voltage) grids in Spain, due to the increasing number of installations. As power monitoring of the generation is in most cases not required, utilities are forced to make assumptions on PV power generation in order to perform network planning studies for both peak demand and contingency analysis. These assumptions increase errors committed during the analysis, as the number of PV installations increases. This paper presents a methodology for estimating PV active power generation values for planning purposes in MV and LV power systems, from historic generation data, based on the development of correlation models. This methodology is applied to three different examples, using predictors based on real registered data. The methodology was also applied in a typical grid study and it's error was determined. (C) 2013 Elsevier Ltd. All rights reserved.

  • Contribution of type-2 wind turbines to sub-synchronous resonance damping

     de Prada Gil, Mikel; Mancilla David, Fernando; Domínguez García, José Luis; Muljadi, Eduard B.; Singh, Mohit B.; Gomis Bellmunt, Oriol; Sumper, Andreas
    International journal of electrical power and energy systems
    Date of publication: 2014-02
    Journal article

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    The rapidly increasing level in wind power penetration is leading to a modification of power system dynamics. Transmission system operators are concerned about this, and are requiring wind farms to comply with some grid codes. For this reason, it is important to determine the grid support capabilities of wind farms, in order to fulfill all current and future requirements. The aim of this paper is to demonstrate that partial-variable speed wind turbines (WT) employing a wound rotor induction generator equipped with an controllable external resistor (so-called Type-2 WTs) are capable to damp Sub-Synchronous Resonance (SSR) occurring on close synchronous generators, when they are connected through a series compensated transmission lines to the main grid. The IEEE first benchmark model (IEEE-FBM) for SSR studies is adopted as test case and modified with an aggregated Type-2 WPP model connected to the system. A damping control algorithm based on adjusting the average value of the external rotor resistance via the control its chopper's duty cycle is presented and implemented using PSCAD/EMTDC software. Detailed computer simulations suggest effective contribution of Type-2 WT to damp SSR affecting synchronous generators. © 2013 Elsevier Ltd. All rights reserved.

  • Technical and economic assessment of offshore wind power plants based on variable frequency operation of clusters with a single power converter

     de Prada Gil, Mikel; Gomis Bellmunt, Oriol; Sumper, Andreas
    Applied energy
    Date of publication: 2014-07-15
    Journal article

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    The aim of this paper is to analyse, from the technical and economic point of view, the suitability of a proposed Offshore Wind Power Plant (OWPP) scheme based on removing the individual power converters of each wind turbine and connecting a turbine cluster (or an entire WPP) to a single large power converter (SLPC), by means of a centralised control. This proposed concept is specially worthwhile for HVDC interfaced offshore or remote WPPs where a common power converter (LCC or VSC) is required at the connection point of the wind farms. According to this approach, two WPP topologies are studied depending on whether the SLPC operates at variable or constant frequency (SLPC-VF or SLPC-CF). A detailed methodology to assess any WPP layout under any wind condition is presented and applied to a case study. In order to obtain accurate results, a wake model considering single, partial and multiple wakes within a WPP is considered. The implemented algorithm takes into account the steady-state and maintenance (preventive and corrective) energy losses, as well as investment and operation and maintenance (O&M) costs, to provide a precise technical and economic assessment of each WPP topology analysed. Due to the uncertainty of certain parameters, a sensitivity analysis varying the cost and efficiency of the individual power converters of each wind turbine, as well as the main economic indicators, has been performed. The results obtained suggests a good potential for the SLPC-VF scheme achieving a total cost saving of up to 6% compared to the conventional WPP topology, based on individual power converters connected to each turbine. Likewise, the effectiveness of implementing an optimum electrical frequency calculation algorithm for variable frequency operation within the WPP is demonstrated as a greater economic benefit can be realised for SLPC-VF instead of SLPC-CF scheme. (C) 2014 Elsevier Ltd. All rights reserved.

  • Participation of wind power plants in system frequency control: Review of grid code requirements and control methods

     Díaz González, Francisco; Hau, Melanie; Sumper, Andreas; Gomis Bellmunt, Oriol
    Renewable and sustainable energy reviews
    Date of publication: 2014-06-01
    Journal article

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    Active power reserves are needed for the proper operation of an electrical system. These reserves are continuously regulated in order to match the generation and consumption in the system and thus, to maintain a constant electrical frequency. They are usually provided by synchronized conventional generating units such as hydraulic or thermal power plants. With the progressive displacement of these generating plants by non-synchronized renewable-based power plants (e.g. wind and solar) the net level of synchronous power reserves in the system becomes reduced. Therefore, wind power plants are required, according to some European Grid Codes, to also provide power reserves like conventional generating units do. This paper focuses not only on the review of the requirements set by Grid Codes, but also on control methods of wind turbines for their participation in primary frequency control and synthetic inertia.

  • Contributions of Flywheel Systems in Wind Power Plants  Open access

     Díaz González, Francisco
    Defense's date: 2013-09-30
    Universitat Politècnica de Catalunya
    Theses

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    El progressiu desplaçament de plantes de generació convencionals per part de plantes de generació de tipus renovable, com els parcs eòlics, pot afectar el comportament i la planificació del sistema elèctric. Primer, l'estabilitat pot ser compromesa ja que el sistema elèctric resulta més vulnerable davant canvis abruptes provocats per les càrregues del sistema o desconnexions no programades de generadors. Això es degut a que les turbines eòliques no estan sincronitzades amb la freqüència elèctrica del sistema ja que la seva connexió és a través de convertidors electrònics de potència. Segon, degut a la gran variabilitat del vent, la potència elèctrica generada per les turbines eòliques no és constant ni controlable. En aquest sentit, la qualitat de la potència del parc eòlic es pot veure compromesa, ja que es poden detectar nivells apreciables d'harmònics i emissions de "flicker" degudes a les ràpides variacions de la potència generada pel parc eòlic.Per aquests motius, els operadors dels sistemes elèctrics fan gradualment més restrictius els requeriments de connexió dels parcs eòlics al sistema elèctric. Aquestes regulacions requereixen als parcs eòlics que es comportin en molts aspectes com plantes de generació convencional. Entre d'altres requeriments, els parcs eòlics han de proveir serveis auxiliars per a la operació del sistema elèctric com també el suport en el control dels nivells de voltatge i freqüència de la xarxa; oferir suport durant curtcircuits; i mantenir uns nivells mínims en la qualitat de la potència generada.Els sistemes d'emmagatzematge d'energia poden millorar la controlabilitat de la potència generada pels parcs eòlics i ajudar a aquests a proveir serveis auxiliars al sistema elèctric, afavorint així la seva integració a la xarxa. Aquesta tesi tracta l'aplicació en parcs eòlics dels sistemes d'emmagatzematge d'energia basats en volants d'inèrcia. La tesi introdueix les bases de diversos sistemes d'emmagatzematge i identifica les seves potencials aplicacions en parcs eòlics en base a una extensa revisió bibliogràfica. El treball continua amb la posta a punt d'un equipament de laboratori, que configura un sistema d'emmagatzematge d'energia basat en un volant d'inèrcia.Següents capítols de la tesi estudien l'aplicació dels volants d'inèrcia per a esmorteir el perfil fluctuant de la potència generada pels parcs eòlics. Els treballs es focalitzen en la definició dels criteris per a la operació òptima dels volants d'inèrcia per la seva aplicació d'esmorteir el perfil fluctuant de potencia eòlica, i també en el disseny i validació experimental dels algoritmes de control desenvolupats per governar el sistema d'emmagatzematge.Els capítols finals de la tesi tracten sobre el suport al control de freqüència per part dels parcs eòlics. S'ofereix una extensa revisió bibliogràfica respecte els requeriments indicats pels operadors del sistema elèctric en aquest sentit. A més, aquesta revisió cobreix els mètodes de control dels parcs eòlics i turbines eòliques per la seva participació en el suport al control de freqüència. Les conclusions extretes serveixen per proposar sistemes de control de parcs eòlics i de turbines eòliques per proveir el servei de control de freqüència. Aquest treball, també contempla la inclusió de volants d'inèrcia en els parcs eòlics.Dels resultats de la tesi se'n dedueix l'important potencial dels sistemes d'emmagatzematge d'energia per a afavorir la integració a la xarxa dels parcs eòlics. La controlabilitat de la potència dels volants d'inèrcia, afavoreix el seu ús per reduir la variabilitat de la potència generada pels parcs eòlics, millorant així la qualitat de potència del mateix. A més, els volants d'inèrcia poder ajudar als parcs eòlics a complir amb els requeriments per a la seva integració.

    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.

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    Deep offshore wind farm planning and cost calculation tools  Open access

     Perez, German; Lopez Mendia, Joseba; Val, Laura; Sumper, Andreas; Schuon, Frieder; de Prada Gil, Mikel; Aragües, Monica; Lopes, Helder; Ergun, Hakan; van Hertem, Dirk
    European Wind Energy Association Conference
    Presentation of work at congresses

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    In planning the installation and operation of wind turbines in the offshore environment, finding new technological solutions is a key element for the economic success of offshore wind projects and represents a completely new challenge compared to their onshore counterpart. The tendency is that wind turbines will continue growing larger and more powerful and will be installed further away and in deeper waters, leading to more complex infrastructures and greater challenges. There¿s a proven experience in the planning and front end engineering of fixed offshore wind farms. Promoters and engineering companies have tools for the costs calculation and wind farm planning, that support the decision making process for the investment. In deep offshore wind farms, there¿s still a lack of this type of tools due to the development stage of the technology: only two full scale prototypes installed. These tools can help in the optimization of the wind farm and costs reduction.

  • Type-2 wind turbine with additional sub-synchronous resonance damping

     de Prada Gil, Mikel; Domínguez García, José Luis; Mancilla David, Fernando; Muljadi, Eduard B.; Singh, Mohit B.; Gomis Bellmunt, Oriol; Sumper, Andreas
    IEEE Green Technologies Conference
    Presentation's date: 2013-04
    Presentation of work at congresses

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    Wind turbines (WTs) employing a wound rotor induction generator with adjustable external resistors are known as Type-2 WTs. This WT topology is available in USA since 2001. This WT is regulated by controlling its pitch angle and its external rotor resistor to operate as a variable slip WT. The slip range can reach up to 10% above synchronous speed. This paper demonstrates that with a proper control, Type-2 WTs are capable to damp out sub synchronous resonance (SSR) oscillations commonly found in series-compensated transmission lines. The size of wind power plant (WPP) has increased over the years and some WPP exceeds 500 MW. They can be treated as energy sources which can regulate the power delivered to the grid. In order to analyze the capability of Type-2 WPPs to damp power system oscillations, the IEEE first benchmark model for SSR studies is modified with an aggregated Type-2 WPP model connected to the system. An additional control loop is implemented to modulate the effective rotor resistance so that SSR oscillations can be damped. The models are implemented and simulated using PSCAD/EMTDC software platform.

  • Distribution system reconfiguration using genetic algorithm based on connected graphs

     Tomoiaga, Bodgan; Chindris, Mircea; Sumper, Andreas; Villafafila Robles, Roberto; Sudria Andreu, Antoni
    Electric power systems research
    Date of publication: 2013-11
    Journal article

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    The reconfiguration of a power distribution system, by exchanging the functional links between its elements, represents one of the most important procedures to improve the performance in the operation of a distribution system. The optimization through reconfiguration (or optimal reconfiguration) of a power distribution system is not a new problem but still represents a difficult one and is specified in some strategies for smart grids. The paper addresses this problem as a single objective one, where, as main criterion, active power losses have been chosen. There is no unique acceptance regarding which approach (based on heuristics, meta-heuristics, genetic algorithms, etc.) is the most proper to use in order to solve this problem. The most important thing is how the specific knowledge of the problem domain is used and modeled in the implementation. Moreover, the indices which can quantify the quality of a reconfiguration method consist in runtime and the obtained solution and these indices can be confirmed only by experimental results. In order to solve the problem (to search and find the optimal solution) an original genetic algorithm based on connected graphs is proposed. Comparative tests performed on some test systems demonstrated the accuracy and the promptness of the proposed algorithm. AbbreviationsPactive power lossesVinodes voltagesI ijelectric current through a branch ijijbinary variable representing the status of a tie line (0 - open, 1 - closed)nthe number of electric system nodespthe number of connected componentsXthe set of power system nodesEthe set of power system lines (branches).

  • Experimental validation of a real time energy management system for microgrids in islanded mode using a local day-ahead electricity market and MINLP

     Marzband, Mousa; Sumper, Andreas; Domínguez García, José Luis; Gumara Ferret, Ramon
    Energy conversion and management
    Date of publication: 2013-12
    Journal article

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    Energy management systems (EMS) are vital supervisory control tools used to optimally operate and schedule Microgrids (MG). In this paper, an EMS algorithm based on mixed-integer nonlinear programming (MINLP) is presented for MG in islanding mode considering different scenarios. A local energy market (LEM) is also proposed with in this EMS to obtain the cheapest price, maximizing the utilization of distributed energy resources. The proposed energy management is based on LEM and allows scheduling the MG generation with minimum information shared sent by generation units. Load demand management is carried out by demand response concept to improve reliability and efficiency as well as to reduce the total cost of energy (COE). Simulations are performed with real data to test the performance and accuracy of the proposed algorithm. The proposed algorithm is experimentally tested to evaluate processing speed as well as to validate the results obtained from the simulation setup on a real MG Testbed. The results of the EMS-MINLP based on LEM are compared with a conventional EMS based on LEM. Simulation and experimental results show the effectiveness of the proposed algorithm which provides a reduction of 15% in COE, in comparison with conventional EMS. © 2013 Elsevier Ltd. All rights reserved.

  • Energy management of flywheel-based energy storage device for wind power smoothing

     Díaz González, Francisco; Sumper, Andreas; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel
    Applied energy
    Date of publication: 2013-10
    Journal article

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    Power fluctuations of wind generators may affect power quality especially in weak or isolated grids. This paper proposes an energy management strategy for a flywheel-based energy storage device. The aim of the flywheel is to smooth the net power flow injected to the grid by a variable speed wind turbine. The design of the energy management strategy is conducted through several phases. First, a definition and determination of the optimal operation of the storage device is carried out through the formulation and deterministic solution of an optimization problem in GAMS. Based on this solution, an online energy management algorithm is proposed to achieve a close to optimal operation of the flywheel. This algorithm determines the set points of the torque control of the flywheel electrical machine. The proposed methodology is illustrated by simulations.

  • Modeling, control and experimental validation of a flywheel-based energy storage device

     Díaz González, Francisco; Sumper, Andreas; Gomis Bellmunt, Oriol; Villafafila Robles, Roberto
    EPE journal
    Date of publication: 2013-06
    Journal article

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    This work deals with the modeling, control and experimental validation of a flywheel-based energy storage device. The system is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine (PMSM). The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while an instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP's). The modeling and control system design has been validated after executing several experiments. Other characteristics such as the torque losses of the system as well as the system performance concerning energy rating, power rating and energy efficiency characteristics are determined experimentally.

  • Experimental evaluation of a real time energy management system for stand-alone microgrids in day-ahead markets

     Marzband, Mousa; Sumper, Andreas; Ruiz Álvarez, Albert; Domínguez García, José Luis; Tomoiaga, Bogdan
    Applied energy
    Date of publication: 2013-06-01
    Journal article

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    A Microgrid (MG) Energy Management System (EMS) is a vital supervisory control to make decisions regarding the best use of the electric power generation resources and storage devices within this MG. This paper presents an operational architecture for Real Time Operation (RTO) of an islanded MG. This architecture considers two different parts including Central Control Unit (CCU) and MG Testbed. CCU implements an EMS based on Local Energy Market (LEM) to control a MG. In order to reach this objective, this unit executes Day Ahead Scheduling (DAS) and Real Time Scheduling (RTS). Regarding DAS, a Modified Conventional EMS (MCEMS) based on LEM (MCEMS-LEM) algorithm has been proposed to find out hourly power set-points of Distributed Energy Resources (DERs) and customers. LEM is also presented in MCEMS-LEM to obtain the best purchasing price in Day-Ahead Market (DAM), as well as to maximize the utilization of existing DER. With regard to RTS, it must update and feedback the power set-points of DER by considering the results of DAS. The presented architecture is flexible and could be used for different configurations of MGs also in different scenarios. Simulations and experimental evaluations have been carried out using real data to test the performance and accuracy of the MG testbed. This paper aims to operate the MG in islanded mode, ensuring uninterruptable power supply services and reducing the global cost of generated power. Results demonstrate the effectiveness of the proposed algorithm and show a reduction in the generated power cost by almost 8.5%.

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    Pareto optimal reconfiguration of power distribution systems using a genetic algorithm based on NSGA-II  Open access

     Tomoiaga, Bogdan; Chindris, Mircea; Sumper, Andreas; Sudria Andreu, Antoni; Villafafila Robles, Roberto
    Energies
    Date of publication: 2013-03-06
    Journal article

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    Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important measures which can improve the operational performance of a distribution system. The authors propose an original method, aiming at achieving such optimization through the reconfiguration of distribution systems taking into account various criteria in a flexible and robust approach. The novelty of the method consists in: the criteria for optimization are evaluated on active power distribution systems (containing distributed generators connected directly to the main distribution system and microgrids operated in grid-connected mode); the original formulation (Pareto optimality) of the optimization problem and an original genetic algorithm (based on NSGA-II) to solve the problem in a non-prohibitive execution time. The comparative tests performed on test systems have demonstrated the accuracy and promptness of the proposed algorithm.

    Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important measures which can improve the operational performance of a distribution system. The authors propose an original method, aiming at achieving such optimization through the reconfiguration of distribution systems taking into account various criteria in a flexible and robust approach. The novelty of the method consists in: the criteria for optimization are evaluated on active power distribution systems (containing distributed generators connected directly to the main distribution system and microgrids operated in grid-connected mode); the original formulation (Pareto optimality) of the optimization problem and an original genetic algorithm (based on NSGA-II) to solve the problem in a non-prohibitive execution time. The comparative tests performed on test systems have demonstrated the accuracy and promptness of the proposed algorithm.

  • Modeling of second generation HTS cables for grid fault analysis applied to power system simulation

     Del-Rosario Calaf, Gerard; Lloberas Valls, Joaquim; Sumper, Andreas; Granados García, Xavier; Villafafila Robles, Roberto
    IEEE transactions on applied superconductivity
    Date of publication: 2013
    Journal article

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  • The optimization of microgrids operation through a heuristic energy management algorithm

     Tomoiaga, Bogdan; Chindris, Mircea; Sumper, Andreas; Marzband, Mousa
    Advanced Engineering Forum
    Date of publication: 2013
    Journal article

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  • Monitoring power quality in microgrids based on disturbances propagation algorithms

     Miron, Anca; Chindris, Mircea; Sumper, Andreas
    Advanced Engineering Forum
    Date of publication: 2013-06
    Journal article

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  • Economic cost analysis of stand-alone hybrid microgrids with minimum COE using HOMER

     Marzband, Mousa; Khaneh Zarrin, Reza; Sumper, Andreas; Baghramian, Alfred
    Majlesi Journal of Energy Management
    Date of publication: 2013
    Journal article

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  • Cables and lines

     Pezzini, Paola; Sumper, Andreas
    Date of publication: 2012-04
    Book chapter

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  • Industrial heating processes

     Chindris, Mircea; Sumper, Andreas
    Date of publication: 2012-04
    Book chapter

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  • Dynamic model of an HTS cable for power grid simulation

     Del-Rosario Calaf, Gerard; Sumper, Andreas; Granados García, Xavier; Sudria Andreu, Antoni; Villafafila Robles, Roberto
    Physics Procedia
    Date of publication: 2012
    Journal article

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  • Tendencias en el desarrollo de las smart grids

     Sumper, Andreas
    Automática e instrumentación
    Date of publication: 2012-09
    Journal article

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  • Optimum voltage control for loss minimization in HVDC multi-terminal transmission systems for large offshore wind farms

     Aragües Peñalba, Mónica; Egea Alvarez, Agustí; Gomis Bellmunt, Oriol; Sumper, Andreas
    Electric power systems research
    Date of publication: 2012-08
    Journal article

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  • Aportaciones al modelado de la generación fotovoltaica para la planificación de la red de distribución  Open access

     Ramon Marin, Miguel Angel
    Defense's date: 2012-11-08
    Department of Electrical Engineering, Universitat Politècnica de Catalunya
    Theses

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    In this thesis it have been explained the problems that the electric distribution companies in Spain have to plan and operate their power networks, having no detailed measurements of instant active power of a large number of non-programmable generators connected to them. The main objective is to reduce errors and difficulties that this lack of information generates. It has been analyzed the specific case of photovoltaic generators (PV), representing at the end of 2011, a 94.6 % of the special regime generators connected to the power networks in Spain, and have an average power of 72 kW per plant at the end of 2011. This means that are mainly connected to the distribution network, so we study the specific issues regarding the planning of the distribution network. It is defined that prediction models of solar irradiance are divided into parametric and decomposition. The ASHRAE parametric model prediction of solar irradiance is described, checking that its instant error levels are not negligible when compared with real data, since it does not include components that provide greater instant solar irradiance variability, such as atmospheric phenomena. It has been described a model based on the usability for the prediction of instantaneous power of PV generation, which is based on an hourly rate of sunlight (Kt) to transfer the extraterrestrial solar irradiation to a horizontal surface on Earth ¿s surface. It has been seen that the definition of the statistical function that defines Kt, makes the difference between the different models based on usability. It has been developed a proposed solution, which allows the development of models using predictors measured at the Earth¿s s urface, which incorporate the variability of atmos pheric phenomena. It has been evaluated the available data for the distribution companies, as well as specified the conditions necessary to develop specific models to be applied in distribution network planning. The proposed solution consists in a systematic methodology for developing models, based on historical data, which provides a response to a wide range of applications for distribution network analysis. It has been shown that the geographic scope of validity of the developed models exceeds the average needs for distribution network planning. It have been developed three case studies, where application of the methodology has been developed, based on real data of a distribution network in the province of Lleida, Spain. Also, it has been found that the models needed for photovoltaic plants with solar follower are different from those needed for photovoltaic plants without follower, because they need to be developed from different predictors. Contributions have been developed based on examples of application of the developed models to network analysis, based on another set of real data from the distribution network in Lleida, corresponding to a medium voltage line (25 kV). Based on this example it have been described the possible options when applying the methodology, as well as several different situations, drawing conclusions. Furthermore, it have been evaluated the possible seasonality of the models, and therefore, the contribution that would get from the development of specific models for each quarter, against the development of a single model for the prediction of the whole year. Barcelon

    Mediante la presente tesis se ha planteado la problemática existente en las empresas de distribución en España, que han de planificar y operar sus redes eléctricas sin disponer de medidas de potencia activa instantánea de un alto número de generadores fotovoltaicos conectados a las mismas, con el objetivo principal de reducir los posibles errores y dificultades que dicha falta de información genera. Se ha estudiado el caso concreto de los generadores fotovoltaicos, que representan al cierre del año 2011 el 94,6% de los generadores en régimen especial conectados en las redes eléctricas en España, y que al contar con una potencia media por instalación de 72 kW al cierre del año 2011, están mayoritariamente conectados a la red de distribución, por lo que se estudian las problemáticas especificas en cuanto a la planificación de dicha red. Con el fin de predecir la producción fotovoltaica de una forma indirecta, ya que no se dispone de la totalidad de los datos necesarios directamente, se precisan modelos basados en los predictores disponibles, como la irradiancia solar. Se ha definido que los modelos de predicción de la irradiancia solar se dividen en paramétricos y de descomposición. Se ha descrito el modelo paramétrico ASHRAE de predicción de la irradiancia solar, comprobando que obtiene unos niveles de error que no son despreciables al compararlos con datos reales, dado que no incorpora los componentes que aportan mayor variabilidad a dicha irradiancia solar instantánea, como son los fenómenos atmosféricos. Se ha descrito un modelo de descomposición basado en la utilizabilidad, para la predicción de la potencia instantánea de generación de una planta fotovoltaica, que se basa en un índice horario de claridad solar (Kt) para trasladar la irradiación solar extraterrestre a una superficie horizontal en la superficie terrestre. Se ha podido ver que es la definición de la función estadística que define a Kt, lo que marca la diferencia entre los diferentes modelos basados en la utilizabilidad. Por tanto, los modelos existentes o bien no consideran los fenómenos que tienen lugar en la superficie terrestre, o bien los consideran de forma estadística para largos períodos. Se ha desarrollado una propuesta de solución que permite el desarrollo de modelos utilizando predictores medidos en la superficie terrestre, los cuales incorporan la variabilidad de los fenómenos atmosféricos. Se incorpora en la elaboración de dicha solución la evaluación de los datos disponibles en el entorno de las compañías distribuidoras, así como la especificación de los condicionantes necesarios en el modelado especifico a desarrollar para su utilización en la planificación de la red de distribución. La propuesta de solución consiste en una metodología sistemática de desarrollo de modelos, a partir del tratamiento estadístico de datos reales históricos, que permite dar una respuesta a una amplia gama de aplicaciones de análisis de la red de distribución. Se ha demostrado que el ámbito geográfico de validez de los modelos supera ampliamente las necesidades medias específicas para su utilización en la planificación de la red de distribución. Se han desarrollado ejemplos reales de aplicación de la metodología desarrollada, basados en datos reales de la red de distribución en la provincia de Lleida, en España. Con ellos se ha podido comprobar que los modelos necesarios para plantas fotovoltaicas con seguidor son diferentes de los necesarios para plantas fotovoltaicas sin seguidor, pues necesitan desarrollarse a partir de predictores diferentes. Se han desarrollado aportaciones en base a ejemplos de aplicación de los modelos desarrollados al análisis de red, basados en otra serie de datos reales de la red de distribución en Lleida, correspondientes a una línea de distribución en media tensión (25 kV). En base a dicho ejemplo se han descrito las posibles opciones a la hora de la aplicación de la metodología, así como se han analizado diversas casuísticas que se pueden presentar, extrayendo conclusiones. Así mismo, se ha evaluado la posible estacionalidad de los modelos, y por tanto, la aportación que conllevaría el desarrollo de modelos específicos para cada trimestre del año, frente al desarrollo de un único modelo para la predicción de todo el año. También se han presentado ejemplos de aplicación de los modelos a la resolución de un caso mediante un flujo de cargas.

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    Modeling and validation of a flywheel energy storage lab-setup  Open access

     Díaz González, Francisco; Sumper, Andreas; Gomis Bellmunt, Oriol; Villafafila Robles, Roberto
    IEEE PES Innovative Smart Grid Technologies
    Presentation of work at congresses

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    This work deals with the modeling, control and experimental validation of a flywheel test bench which is part of IREC's lab-scale microgrid. The storage device has been designed as a proof of concept. It is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine. The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while the instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP's). The modeling and control system design has been validated after executing several experiments.

    This work deals with the modeling, control and experimental validation of a flywheel test bench which is part of IREC’s lab-scale microgrid. The storage device has been designed as a proof of concept. It is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine. The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while the instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP’s). The modeling and control system design has been validated after executing several experiments.

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    Requirements for EV charge stations with photovoltaic generation and storage  Open access

     Cairó, Ignasi; Sumper, Andreas
    IEEE Innovative Smart Grid Technologies Conference Europe
    Presentation of work at congresses

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    With the increase in electric mobility, public and private charge facilities will be required to provide solutions adjusted to the actual needs and requirements. A new methodology for dimensioning charge stations for electric vehicles (EVs) is presented in this paper. Such proposal is based on the Markov chains, and uses as output rates, the capabilities of the charge station in providing energy from the sun through photovoltaic generation, stored energy in local batteries and also as a back-up the power grid. A numerical result is also presented for a better understanding of the process.

    With the increase in electric mobility, public and private charge facilities will be required to provide solutions adjusted to the actual needs and requirements. A new methodology for dimensioning charge stations for electric vehicles (EVs) is presented in this paper. Such proposal is based on the Markov chains, and uses as output rates, the capabilities of the charge station in providing energy from the sun through photovoltaic generation, stored energy in local batteries and also as a back-up the power grid. A numerical result is also presented for a better understanding of the process.

    Postprint (author’s final draft)

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    Power system stabiliser capability of offshore wind power plants  Open access

     Domínguez García, José Luis; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas; Sudria Andreu, Antoni
    European Wind Energy Conference & Exhibition
    Presentation's date: 2012-04
    Presentation of work at congresses

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    Nowadays, wind power generation is being located offshore because of its higher wind speed at lower height and larger installation zones in comparison with onshore technologies. Recently, the concept of wind power plant has been introduced as a result of the increment of wind power penetration in power systems. Transmission system operators are requiring wind power generation to help to power system with some ancillary services such as fault ride through or power system stabiliser capability. Therefore, it is important to study power system stabiliser capability of wind power plants. In this paper, a comparison of various power system stabiliser schemes is presented. The effect of the distance from the shore tie-line to the offshore wind farm on the controller response is also evaluated. These studies show that offshore wind power plants have promising power system stabiliser capability even using local input signals.

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    Energy management system of hybrid microgrid with energy storage  Open access

     Marzband, Mousa; Sumper, Andreas; Chindris, Mircea; Tomoiaga, Bogdan
    World Energy Systems Conference
    Presentation's date: 2012-06-28
    Presentation of work at congresses

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    The economic scheduling of the generation units is playing a significant role in the energy management of the hybrid stand alone microgrid. Energy storage is an increasingly important part of the renewable energy sector because of the need to store power during peak production times for use in off-peak periods. This paper describes an energy management system (EMS) for an islanded microgrid (MG) comprising wind energy conversion system (WECS),photovoltaic (PV), energy storage (ES) system, and microturbine (MT) for calculating the battery charging price (BCP) factor. To reach this objective, firstly the battery system has been modeled using the presented equations then various scenarios is applied by technically limited such as the power, voltage and current applied to charge and discharge of the battery.

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    Dimensioning electric charging posts for PEV  Open access

     Cairó, Ignasi; Cruz, Miguel; Sumper, Andreas
    International Conference on Electricity Distribution
    Presentation's date: 2012-05-29
    Presentation of work at congresses

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    This paper represents a new analysis method for the estimation of the required charging infrastructure for the electric vehicles (EV’s). The study is based on a real metropolitan area, taking real data from transport habits, and a prediction of certain degree of penetration of EV’s. To cope with this analysis, is the application of powerful tools, used for example in telecommunication systems such as Markov chains, and applied here into EV’s necessities and charging stations infrastructures. This theory is applied in a real example to provide more insight on how can be applied in real circumstances.

  • Modeling and control of a pitch-controlled variable-speed wind turbine driven by a DFIG with frequency control support in PSS/E

     de Prada Gil, Mikel; Sumper, Andreas; Gomis Bellmunt, Oriol
    IEEE conference on Power Electronics and Machines in Wind Applications
    Presentation's date: 2012-07
    Presentation of work at congresses

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  • Sistemas de transporte para grandes centrales eólicas marinas

     Gomis Bellmunt, Oriol; Montesinos Miracle, Daniel; Boix Aragonès, Oriol; Sumper, Andreas; Junyent Ferré, Adrià
    Participation in a competitive project

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  • PSS controller for wind power generation systems

     Domínguez García, José Luis; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas
    International journal of modern physics B
    Date of publication: 2012
    Journal article

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  • Power oscillation damping supported by wind power: A review

     Domínguez García, José Luis; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas
    Renewable and sustainable energy reviews
    Date of publication: 2012-09-03
    Journal article

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    Probabilistic method to assess the impact of charging of electric vehicles on distribution grids  Open access

     Valsera-Naranjo, Eduardo; Sumper, Andreas; Villafafila Robles, Roberto; Martínez Vicente, David
    Energies
    Date of publication: 2012-05-18
    Journal article

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    This paper describes a grid impact analysis of charging electric vehicles (EV) using charging curves with detailed battery modelling. A probabilistic method using Monte Carlo was applied to a typical Spanish distribution grid, also using mobility patterns of Barcelona. To carry out this analysis, firstly, an IEEE test system was adapted to a typical distribution grid configuration; secondly, the EV and its battery types were modeled taking into account the current vehicle market and the battery characteristics; and, finally, the recharge control strategies were taken into account. Once these main features were established, a statistical probabilistic model for the household electrical demand and for the EV charging parameters was determined. Finally, with these probabilistic models, the Monte Carlo analysis was performed within the established scenario in order to study the lines’ and the transformers’ loading levels. The results show that an accurate model for the battery gives a more precise estimation about the impact on the grid. Additionally, mobility patterns have been proved to be some of the most important key aspects for these type of studies.

  • A review of energy storage technologies for wind power applications

     Díaz González, Francisco; Sumper, Andreas; Gomis Bellmunt, Oriol; Villafafila Robles, Roberto
    Renewable and sustainable energy reviews
    Date of publication: 2012-05
    Journal article

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  • Power generation efficiency analysis of offshore wind farms connected to a SLPC (single large power converter) operated with variable frequencies considering wake effects

     de Prada Gil, Mikel; Gomis Bellmunt, Oriol; Sumper, Andreas; Bergas Jane, Joan Gabriel
    Energy
    Date of publication: 2012-01
    Journal article

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  • Control of a wind farm based on synchronous generators with a central HVDC-VSC converter

     Gomis Bellmunt, Oriol; Junyent Ferré, Adrià; Sumper, Andreas; Bergas Jane, Joan Gabriel
    IEEE transactions on power systems
    Date of publication: 2011-08
    Journal article

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  • Reactive power dispatch in wind farms using particle swarm optimization technique and feasible solutions search

     Martinez Rojas, Marcela; Sumper, Andreas; Gomis Bellmunt, Oriol; Sudria Andreu, Antoni
    Applied energy
    Date of publication: 2011-12
    Journal article

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    In this paper, an optimization method for the reactive power dispatch in wind farms (WF) is presented. Particle swarm optimization (PSO), combined with a feasible solution search (FSSPSO) is applied in order to optimize the reactive power dispatch, taking into consideration the reactive power requirement at point of common coupling (PCC), while active power losses are minimized in a WF. The reactive power requirement at PCC is included as a restriction problem and is dealt with feasible solution search. Finally an individual set point, particular for each wind turbine (WT), is found. The algorithm is tested in a WF with 12 WTs, taking into consideration different control options and different active power output levels.

  • Dynamic simulation of HTSC cables with a conventional simulation program

     Gelabert-Serra, Miquel Jeroni; Granados García, Xavier; Sumper, Andreas; Sudria Andreu, Antoni; Rull Duran, Joan
    IEEE transactions on applied superconductivity
    Date of publication: 2011-06
    Journal article

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  • Life-cycle assessment of a photovoltaic system in Catalonia (Spain)

     Sumper, Andreas; Robledo García, Mercedes; Villafafila Robles, Roberto; Bergas Jane, Joan Gabriel; Andrés-Peiró, Juan
    Renewable and sustainable energy reviews
    Date of publication: 2011-10
    Journal article

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  • Modeling and simulation of the fixed speed wind power generation system for grid studies

     Marzband, Mousa; Sumper, Andreas; Gomis Bellmunt, Oriol; Sudria Andreu, Antoni; Chindris, Mircea
    International Conference on Electrical Power Quality and Utilisation
    Presentation's date: 2011-10-17
    Presentation of work at congresses

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    Power system stabilizer control for wind power to enhance power system stability  Open access

     Domínguez García, José Luis; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas
    International Scientific Conference on Physics and Control
    Presentation's date: 2011-09-05
    Presentation of work at congresses

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    The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation modes. The proposed stabilizer is evaluated by simulation using DigSilent PowerFactory

  • Protection system remote laboratory

     Martinez Perez, Raul; Villafafila Robles, Roberto; Lloret Gallego, Pau; Egea Alvarez, Agustí; Sumper, Andreas; Silos Sanchez, Angel
    Electrical Power Quality and Utilisation
    Presentation's date: 2011-10-17
    Presentation of work at congresses

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  • A utility connected microgrid based on power emulators

     Gomis Bellmunt, Oriol; Sumper, Andreas; Colet Subirachs, Alba; Ruiz Alvarez, Albert; Alvarez Cuevas-Figuerola, Felipe; Sudria Andreu, Antoni
    IEEE Power & Energy Society General Meeting
    Presentation's date: 2011-07
    Presentation of work at congresses

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