1,692 research outputs found
Excelencia en la Gestión Pública vs Privada: un análisis de perfiles a través de los sistemas de Reconocimiento EFQM
Con motivo de la situación actual que vemos a diario en las noticias sobre irregularidades, fraude, corrupción y mala gestión de los recursos económicos públicos, se plantea este trabajo.
El presente estudio nos embarca en el análisis de la gestión del sector público, a través de un examen profundo sobre la calidad, el Modelo EFQM y la comparativa de los perfiles del sector público y privado en materia de calidad y sus características propias. Por último, se finaliza con el análisis de las empresas que cuentan con Reconocimientos de excelencia en el sector público por comunidades autónomas, por sectores de actividad y por niveles de excelencia y su comparación con el sector privado.Universidad de Sevilla. Grado en Finanzas y Contabilida
Nature based-solutions for water reuse: 20 years of performance evaluation of a full-scale constructed wetland system
Water reuse is becoming an important tool in water resource management in regions with recurrent droughts and water shortages, such as the Mediterranean. However, there are still obstacles preventing the multiple application of water reuse projects, such as social acceptability and financial problems. In this context, the use of green infrastructure such as constructed wetlands in combination with conventional mechanical treatments could represent a very practical alternative. In this article, we present the evaluation of the performance and the water quality obtained by a combined system over a long period of 2 decades. The water reuse system is located in Granollers, Barcelona, Spain, and consists of 3 elements: wetland, mechanical reclamation plant and distribution network. The entire system produces >10,000 m3 annually for garden irrigation, and street and sewerage cleaning, and there are plans for a substantial increase of this water reclaimed flow in the next years. The effluent meets the water reuse standards set by the water regional authority for pH, electrical conductivity, TSS, E. coli, Legionella and Nematodes eggs, either as average or as 90th percentiles. Turbidity standard is met as average but not as 90th percentile (being 10.7 NTU, while the limit 10 NTU). The combination of the green infrastructure, represented by the wetland, and the conventional mechanical system, represented by the reclamation plant, results in excellent water quality suitable for the irrigation of public gardens and the cleaning of streets. The integration of both elements increases the reliability of the system and contributes to the social acceptance of water reuse. This work presents long-term and complete evidence at a full-scale of the contribution and benefits of nature-based solutions to sustainable water management.Peer ReviewedPostprint (published version
Demand and Storage Management in a Prosumer Nanogrid Based on Energy Forecasting
Energy efficiency and consumers' role in the energy system are among the strategic research topics in power systems these days. Smart grids (SG) and, specifically, microgrids, are key tools for these purposes. This paper presents a three-stage strategy for energy management in a prosumer nanogrid. Firstly, energy monitoring is performed and time-space compression is applied as a tool for forecasting energy resources and power quality (PQ) indices; secondly, demand is managed, taking advantage of smart appliances (SA) to reduce the electricity bill; finally, energy storage systems (ESS) are also managed to better match the forecasted generation of each prosumer. Results show how these strategies can be coordinated to contribute to energy management in the prosumer nanogrid. A simulation test is included, which proves how effectively the prosumers' power converters track the power setpoints obtained from the proposed strategy.Spanish Agencia Estatal de Investigacion ; Fondo Europeo de Desarrollo Regional
Energy management strategy to coordinate batteries and ultracapacitors of a hybrid energy storage system in a residential prosumer installation
Publicado en 2017 International Young Engineers Forum (YEF-ECE), Almada (Portugal), pp. 30-35, doi: 10.1109/YEF-ECE.2017.7935636En los últimos años, los sistemas de energía han experimentado un gran desarrollo como consecuencia de la aparición de la generación distribuida. Las fuentes de energía renovables, los usuarios activos y los vehículos eléctricos juegan un papel fundamental en los sistemas de energía, lo que supone un nuevo tema de investigación. En este escenario, la figura del prosumidor ha ganado relevancia debido a las múltiples ventajas que pueden aportar para mejorar el comportamiento de los sistemas de energía y lograr ahorros de energía y costos. En particular, se presta especial atención a los conjuntos fotovoltaicos (PV) integrados en edificios residenciales con sistemas de almacenamiento de energía (ESS), como baterías o ultracondensadores (UC) o incluso una combinación de ambos en un sistema de almacenamiento de energía híbrido (HESS). Este artículo presenta una estrategia de gestión de energía para intercambiar energía entre las baterías y las UC que forman un HESS instalado con una matriz FV en una vivienda de prosumidores para mantener su banco de UC disponible para satisfacer los requisitos de energía durante el mayor tiempo posible.In recent years, power systems have experimented a great development as a consequence of the apparition of the distributed generation. Renewable energy sources, active users and electric vehicles play a fundamental role in power systems, which has supposed a new topic research. In this scenario, the figure of prosumer has gained relevance due to the multiple advantages that they can contribute to improve the behavior of power systems and to achieve energy and cost savings. In particular, special attention is focus on photovoltaic (PV) arrays integrated in residential buildings with energy storage systems (ESSs), such as batteries or ultracapacitors (UCs) or even a combination of both in a hybrid energy storage system (HESS). This paper presents an energy management strategy to Exchange energy between the batteries and the UCs that form a HESS installed with a PV array in a prosumer dwell in order to maintain its UC bank available to support the energy requirements during the most time possible
Comprehensive study of the benefits of integrating a sharing energy strategy between prosumers
Publicado en IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, Beijing, 2017, pp. 3609-3614, doi: 10.1109/IECON.2017.8216612La actualización de los sistemas de energía en los últimos años debido a la proliferación de la generación distribuida con fuentes de energía renovables, usuarios activos y vehículos eléctricos se ha convertido en un desafío. En este nuevo escenario, los prosumidores juegan un papel importante para amortiguar la curva de consumo y, por lo tanto, contribuir a los requisitos de la red. Los conjuntos fotovoltaicos (PV) integrados en edificios residenciales atraen una atención especial, ya que pueden complementarse con sistemas de almacenamiento de energía (ESS), como baterías o ultracondensadores (UC) o incluso una combinación de ambos, con el objetivo de lograr que los clientes puedan administrar su energía. Las razones anteriores justifican la necesidad de un sistema de gestión de energía (EMS) que coordine el funcionamiento de los dispositivos de almacenamiento de energía de manera optimizada, ya que son caros. En este documento, se propone un sistema de control integral para intercambiar energía entre los dispositivos de almacenamiento híbridos (baterías y UC) de dos viviendas con instalaciones fotovoltaicas con el fin de aumentar la disponibilidad de sus ESS y soportar los requisitos de energía durante el mayor tiempo posible, optimizando tamaños y costos, y evitando la saturación.The upgrade of power systems in the last years due to the proliferation of distributed generation with renewable energy sources, active users and electric vehicles has become a challenge. In this new scenario, prosumers play an important role in order to buffer the consumption curve and, therefore, contributing to the grid requirements. Special attention is attracted by photovoltaic (PV) arrays integrated in residential buildings, because they can be complemented with energy storage systems (ESSs), such as batteries or ultracapacitors (UCs) or even a combination of both, with the aim to achieve that customers could manage their energy. The above reasons justify the need of an energy management system (EMS) that coordinates the operation of the energy storage devices in an optimized way, as they are expensive. In this paper, a comprehensive control system is proposed to exchange energy between the hybrid storage devices (batteries and UCs) of two dwells with PV installations in order to increase the availability of their ESSs and support the energy requirements during the most time possible, optimizing sizes and costs and avoiding saturation.peerReviewe
Active, Reactive and Harmonic Control for Distributed Energy Micro-Storage Systems in Smart Communities Homes
This paper aims to provide control strategies for distributed micro-storage energy systems at the residential level to contribute to smart grid goals. A simulation model of an energy storage system (ESS) charger has been implemented to test these proposed control strategies. The smart community energy management system (SCEMS), acting as an aggregator of resources in the community according to the expected demand and production, sends to each individual home the active and reactive power set-points. Besides, in case the ESS has available capacity, once the SCEMS requirements are satisfied, it is used to absorb the harmonic current components demanded by the household circuitry. It allows a local improvement in the power quality of the demanded current, and thus contributes to the global power quality consumption of the community. Simulation results showing the operation of a local ESS at a home in a Smart Community are presented to validate the proposed control strategies
Improved forecasting-based battery energy management strategy for prosumer systems
Publicado en IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society, Washington D. C., 2018, pp. 6077-6082, doi: 10.1109/IECON.2018.8592892Este trabajo presenta una estrategia de gestión de energía basada en la programación de la operación de la batería en sistemas prosumidores según los datos de pronóstico disponibles con 24 horas de anticipación. El método propuesto busca alcanzar un compromiso beneficioso entre los prosumidores y los operadores de la red de distribución, independientemente del contexto económico específico o las regulaciones técnicas. Se lleva a cabo una mejora para hacer frente a la imprecisión del pronóstico. Los resultados demuestran que ofrece buenas propiedades con respecto a la gestión de energía, con una estimación de reserva de energía almacenada, preservación de la vida útil de la batería y mejora del autoconsumo y la autosuficiencia.This work presents an energy management strategy based on scheduling battery operation in prosumer systems, according to forecast data available 24 hours in advance. The proposed method seeks to reach a beneficial compromise between prosumers and distribution grid operators, independently of specific economic context or technical regulations. An improvement to deal with forecast inaccuracy is carried out. Results demonstrate that it offers good properties regarding energy management, with a stored energy reserve estimation, battery lifetime preservation and self-consumption and selfsufficiency enhancement.peerReviewe
Improvements on the carrier-based control method for a three-level T-type, quasi-impedance-source inverter
The boost feature that characterizes Z-source and quasi-Z-source converters is usually achieved by means of a proper insertion of short-circuit states in the full DC-link. In this work, a novel pulse width modulation carrier-based strategy for a three-phase, three-level T-type, quasi-Z-source inverter is introduced, based on the addition of alternate short-circuits in the two halves of the DC-link bus. This technique achieves better performance, less electromagnetic interference, and lower harmonic distortion of the output line-to-line voltage compared to the traditional methods based on the full DC-link shoot-through. At the same time, generating the switching states is to easy implement.
The proposed strategy permits the use of electronic devices with lower blocking voltage capability, thus improving converter reliability, size, and cost. The new method may be implemented in another multilevel inverter with an impedance-source network as well. A comprehensive simulation study is performed in order to validate the adopted method, with different inverter input voltages, which
is taken as representative of a photovoltaic array. Comparisons are conducted with conventional strategy insertions using the same topology in order to show the improvements achieved.• Junta de Extremadura (Regional Government), Spain. Programa de Becas de Movilidad para Personal Docente e Investigador de la Comunidad Autónoma de Extremadura 2018, por el fondo para el grupo de investigación (GR18087) y el proyecto regional (IB18067).
• Agencia Estatal de Investigación (AEI) y Fondo Europeo de Desarrollo Regional (FEDER) españoles, bajo el Proyecto TEC2016-77632-C3-1-R (AEI / FEDER, UE), y a través de FCT bajo los contratos UID / CEC / 50021/2019 , Pest-E / EEI / LA0021 / 2014 y UID / Multi / 00308/2019.peerReviewe
A smart power electronic multiconverter for the residential sector
El futuro de la red incluye la generación distribuida y las tecnologías de red inteligente. Los sistemas de gestión del lado de la demanda (DSM) también serán esenciales para lograr un alto nivel de confiabilidad y robustez en los sistemas de energía. Para hacer eso, es necesario expandir la Infraestructura de medición avanzada (AMI) y los Sistemas de gestión de energía (EMS). La dirección de la tendencia es hacia la creación de centros de recursos energéticos, como el concepto de comunidad inteligente. Este documento presenta un sistema multiconvertidor inteligente para el sector residencial / vivienda con un Sistema de Almacenamiento de Energía Híbrido (HESS) que consta de supercapacitador y batería, y con integración de fuente de energía fotovoltaica (PV) local. El dispositivo funciona como una unidad de energía distribuida ubicada en cada casa de la comunidad, recibiendo puntos de ajuste de energía activos proporcionados por una comunidad inteligente EMS. Este SGA central es responsable de administrar los flujos de energía activa entre la red eléctrica, las fuentes de energía renovables, los equipos de almacenamiento y las cargas existentes en la comunidad. El multiconvertidor propuesto es responsable de cumplir con los puntos de referencia de potencia activa de referencia con la calidad de potencia adecuada; garantizando que los módulos fotovoltaicos locales funcionen con un algoritmo de seguimiento del punto de máxima potencia (MPPT); y prolongando la vida útil de la batería gracias a un funcionamiento cooperativo del HESS. Se ha desarrollado un modelo de simulación para mostrar el funcionamiento detallado del sistema. Finalmente, se implementó un prototipo de la plataforma de multiconversores y se realizaron algunas pruebas experimentales para validarlo.The future of the grid includes distributed generation and smart grid technologies. Demand Side Management (DSM) systems will also be essential to achieve a high level of reliability and robustness in power systems. To do that, expanding the Advanced Metering Infrastructure (AMI) and Energy Management Systems (EMS) are necessary. The trend direction is towards the creation of energy resource hubs, such as the smart community concept. This paper presents a smart multiconverter system for residential/housing sector with a Hybrid Energy Storage System (HESS) consisting of supercapacitor and battery, and with local photovoltaic (PV) energy source integration. The device works as a distributed energy unit located in each house of the community, receiving active power set-points provided by a smart community EMS. This central EMS is responsible for managing the active energy flows between the electricity grid, renewable energy sources, storage equipment and loads existing in the community. The proposed multiconverter is responsible for complying with the reference active power set-points with proper power quality; guaranteeing that the local PV modules operate with a Maximum Power Point Tracking (MPPT) algorithm; and extending the lifetime of the battery thanks to a cooperative operation of the HESS. A simulation model has been developed in order to show the detailed operation of the system. Finally, a prototype of the multiconverter platform has been implemented and some experimental tests have been carried out to validate it.Ministerio de Economía y Competitividad (España) y Fondos FEDER: Proyecto TEC2013-47316-C3-3-PpeerReviewe
Secondary Control for Storage Power Converters in Isolated Nanogrids to Allow Peer-to-Peer Power Sharing
It is usual in literature that power sharing among grid-forming sources of an isolated microgrid obeys their energy rating, instead of economic agreements between stakeholders, and circulating energy among them is usually avoided. However, these energy interchanges make strong sense and classical power sharing methods must be reformulated in the context of prosumer-based microgrids. This paper proposes a secondary control method for a prosumer-based low-voltage nanogrid that allows for energy interchange between prosumers, where storage systems, together with PV generators, are the controllable grid-forming sources. A power flow technique adapted to islanded microgrids is used for secondary control algorithm and the whole hierarchical control strategy for the prosumer converter is simulated and validated. This hierarchical control consists of three stages: tertiary control plans the energy interchange among prosumers, secondary obtains different voltage and power setpoints for each of the grid-forming sources, and, finally, primary control guarantees stable voltage and frequency values within the nanogrid with droop rules. Inner control loops for the power converter are also defined to track setpoints and assure stable performance. Simulation tests are carried out, which prove the stability of the proposed methods and the accuracy of the setpoint tracking
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