323,061 research outputs found
Grid-Listening and Grid-Ringing: Alternative Concepts for Grid-Following and Grid-Forming within Power Systems Frequency Transients
No full textThe paper introduces the concepts of grid-listening and grid-ringing as alternative ways to interpret the classes of converter control commonly known as grid-following and grid-forming. The intrinsic nature of these two controls define their interaction within the frequency transients in power systems, and in particular with the disturbance propagation and the synchronization process. The grid-following interacts with the oscillations in the system just detecting them: for that, it can be regarded as grid-listening. The grid-forming interacts with the power-frequency oscillations contributing to them: for that, it can be regarded as grid-ringing. This conceptual revisiting is illustrated with a representative system, and further discussed with some examples on a benchmark power syste
Il rilievo della Dichiarazione universale dei diritti umani nella definizione del diritto alla libertà e alla sicurezza personale
No full textThe right to liberty and security of person is enshrined in Article 3 of the Universal Declaration. The drafters clearly attached great importance
to this right. Not only did they include it in one of the first provisions of the Declaration alongside the right to life, but they also decided to expressly prohibit arbitrary deprivations of liberty in a separate provision (Article 9). This chapter investigates the influence that the Universal Declaration has had on the development and interpretation of the numerous treaty-based rules that now establish the right(s) at hand, as well as on the (debated) emergence of relevant customary international rules, by focusing on the Declaration itself and its travaux préparatoires. The aim is to ascertain how the drafting of the Universal Declaration has influenced the definition of this right internationally and whether the definitional issues that emerged at the time still inform the current debate on personal liberty and security
Responsabilità per violazioni dei diritti umani derivanti dalla cooperazione tra organizzazioni internazionali: spunti di riflessione in materia di attribuzione
No full textCOMPARISON OF POWER QUALITY IMPACT OF DIFFERENT PHOTOVOLTAIC INVERTERS: THE VIEWPOINT OF THE GRID
No full textThis paper presents the results of an
experimental analysis performed with the aim of
evaluating the effect of many photovoltaic plants on
power quality of the grid. Several parameters as
voltage and current distortion, flicker, voltage
variations at fundamental frequency and power factor
have been observed. The measured values have been
compared with the limits reported in the standards
and, when possibiIe, their dependence on the
characteristics of the grid in terms of its impedance has
been pointed out
'It was the best of times, it was the worst of times': A tale of detention in time of emergency
No full textSmart grids: the next future of electrical distribution systems
No full textCurrently, the design and operation criteria for electrical distribution networks are fastly changing due to some factors; among these, the progressive penetration of Distributed Generation(DG) is destined to cause deep changes in the existing networks, no longer considered as passive terminations of the whole electrical system. Moreover, the increasing application of Information
Communication Technologies (ICT) will allow the implementation of the so called “smart grids”, determining new interesting scenarios. In the paper the problems and the potential benefits of DG, the possible new electrical distribution system models and the major research projects on smart grids are faced and reported
Il sistema della generazione distribuita. Problematiche di connessione al sistema elettrico.
No full textNegli ultimi anni, grazie anche ai processi di liberalizzazione del mercato dell’energia
elettrica, si è assistito ad uno sviluppo della cosiddetta generazione distribuita, soprattutto
da fonte rinnovabile, il che pone non poche problematiche tra loro interconnesse di carattere sia
tecnico che normativo, economico ed ambientale. In questo lavoro dopo avere brevemente
illustrato i benefici potenziali dovuti all’introduzione di sistemi di generazione distribuita, si
considera il suo impatto sulle reti elettriche di alta, media e bassa tensione analizzando le
principali problematiche inerenti alla pianificazione, progettazione e gestione delle stesse
Fire risk assessment and cable selection for enduser substations
No full textThis paper examines the issues related to fire risk assessment in end-users substations. Fires in substations may be caused by electrical faults, overvoltages, lack of maintenance, etc. It is crucial that fires be confined within the substation, and not propagate into the adjacent environment, where their effects may put at risk personnel, as well as other properties. To reduce this risk of propagation, the choice of cables and the related wiring methods are crucial; in addition, the characteristics of cable chases that route cables from the substation to adjacent rooms is very important. IEEE and IEC fire protection standards for end-user substations are herein discussed, with emphasis on the criteria used to properly select cables for their specific conditions of use and to limit the risk of fires
Electrostatic synchronous generator model of an Inverter-Based Distributed Generators
No full textIn this paper, the idea of modelling the Inverter-Based Distributed Generators by using the concept of Electrostatic synchronous machines is discussed. A mathematical model of the inverter has been established which depends on the dc bus voltage, modulation index and frequency of the system. Two mathematical models have been developed: a small signal model and a steady-state model. These mathematical models will be helpful in studying the stability of a microgrid; especially when studying the transient stability performance of on-grid operation of converter-based distributed generator with multi-machine microgrid. Simulation results using Matlab/Simulink are carried out
- …
