Search results for " grid"

Cascaded H-Bridges Multielvel Inverters: grid connected advanced applications

Power electronics is going to increase in the modern electrical systems. It is well known that the use of power electronics allows the management and the control of the energy flow, obtaining voltage and current waveforms suitable for electrical loads. In this scenario, multilevel power converters are finding increased attention in industry and academia as one of the promising choices of electronic conversion thanks to their features and many different application fields with high power and medium voltage. Moreover, they are fundamental in interfacing electric grid to high power renewable energy systems (i.e. PV, Wind farm, Biomass, Fuel Cell etc.). Nowadays, the research is focused on the …

Adding semantics to cloud computing to enhance service discovery and access

2012

Cloud computing is a technological paradigm that permits to offer computing services over the Internet. This new service model is closely related to previous, well-known distributed computing initiatives such as Web services and grid computing. In the current socio-economic climate, the affordability of cloud computing has gained it popularity among today's innovations. Under these circumstances, more and more cloud services become available. Consequently, it is becoming more and more difficult for service consumers to find and access those cloud services that fulfill their requirements. In this work, a cloud computing ontology is proposed that facilitates a semantic identification, discove…

Construcción de una tipología rural/urbana para los municipios españoles

2016

[ES] Este artículo pretende establecer criterios para delimitar de modo riguroso qué es lo que constituye un territorio rural o urbano, dadas las limitaciones de las metodologías tradicionales. En segundo lugar, se propone una tipología rural/urbana a escala municipal para España tomando en consideración tres criterios: la demografía —combinando densidades con umbrales mínimos de población— la información sobre coberturas y usos del suelo y el grado de accesibilidad desde el mundo rural a las ciudades. El resultado es el establecimiento de seis tipos distintos de municipios.

On the uniform sampling of CIELAB color space and the number of discernible colors

2013

This paper presents a useful algorithmic strategy to sample uniformly the CIELAB color space based on close packed hexagonal grid. This sampling scheme has been used successfully in different research works from computational color science to color image processing. The main objective of this paper is to demonstrate the relevance and the accuracy of the hexagonal grid sampling method applied to the CIELAB color space. The second objective of this paper is to show that the number of color samples computed depends on the application and on the color gamut boundary considered. As demonstration, we use this sampling to support a discussion on the number of discernible colors related to a JND.

Experimental investigation on the effectiveness of basalt-fibre strengthening systems for confining masonry elements

L’impiego di materiali compositi per il rinforzo di colonne in muratura è diventato una pratica ampiamente diffusa nel corso degli ultimi decenni. Questa tecnica, che consiste generalmente nell’applicazione di materiali polimerici fibrorinforzati (Fibre Reinforced Polymer-FRP), ha mostrato buone potenzialità, essendo in grado di garantire notevoli incrementi di resistenza e duttilità dell’elemento rinforzato, grazie ad un’azione di confinamento passivo. Tuttavia, l’impiego di compositi a matrice polimerica presenta alcuni limiti legati soprattutto alle prestazioni delle resine epossidiche, che a causa della loro natura sintetica danno luogo a problemi di compatibilità con il supporto murari…

Creating a semantically-enhanced cloud services environment through ontology evolution

2014

Currently, the availability of Web resources has grown enormously to the point that whatever a user needs at a given moment can potentially be found on the Internet. These resources are not limited to data items anymore, functionality delivered through some sort of service architectural model is also offered on the Internet. In the last few years, cloud computing has emerged as one of the most popular computing models to provide services over the Internet. However, as the number of available cloud services increases, the problem of service discovery and selection arises. Experience indicates that semantic technologies can provide the basis for enhanced and more precise search processes. In …

A new low cost power line communication solution for smart grid monitoring and management

2018

Modern smart grids require the improvement of measurement and communication infrastructures of distribution networks, at both medium voltage (MV) and low voltage (LV) levels. Distributed sensing and measurement systems are needed to provide all necessary data for grid monitoring, control and management, as well as for the implementation of a number of smart functionalities, such as remote control of distributed generators (DGs), real time analysis of power flows, automatic meter reading (AMR), demand side management (DSM), grid automation and so on [1]-[6]. Acquired network data include typical electrical network quantities and status variables (such as powers, voltages, currents, switches …

On the Interconnections of HV–MV Stations to Global Grounding Systems

2019

The interconnection of grounding systems of HV-MV stations via the armors of medium voltage cables, is herein analyzed to verify the effects on touch voltages in ground-fault conditions. The major contributions of this paper are two: the analysis of the impact of an HV ground-fault on a global grounding system (GGS), and the analysis of the parameters that may affect safety due to the interconnection between HV-MV stations and the GGS. The authors have analyzed cases when the connection of an HV-MV station to a GGS improves safety, and then may introduce hazards under ground-fault conditions. Two main issues are herein discussed: 1) the transfer of dangerous voltages to substations, due to …

Teletraffic Engineering for Direct Load Control in Smart Grids

2018

International audience; The traditional paradigm for power grid operation is to continuously adapt energy production to demand. This paradigm is challenged by the increasing penetration of renewable sources, that are more variable and less predictable. An alternative approach is the direct load control of some inherently flexible electric loads to shape the demand. Direct control of deferrable loads presents analogies with flow admission control in telecommunication networks: a request for network resources (bandwidth or energy) can be delayed on the basis of the current network status in order to guarantee some performance metrics. In this paper we go beyond such an analogy, showing that u…

A review of thermochemical energy storage systems for power grid support

2020

Power systems in the future are expected to be characterized by an increasing penetration of renewable energy sources systems. To achieve the ambitious goals of the “clean energy transition”, energy storage is a key factor, needed in power system design and operation as well as power-to-heat, allowing more flexibility linking the power networks and the heating/cooling demands. Thermochemical systems coupled to power-to-heat are receiving an increasing attention due to their better performance in comparison with sensible and latent heat storage technologies, in particular, in terms of storage time dynamics and energy density. In this work, a comprehensive review of the state of art of theore…