1,721,085 research outputs found
Guest Editorial Special Section 'Advances in Lightning Modeling, Computation, and Measurement'
No full textVehicle-to-Home Service via Electric Vehicle Energy Storage Virtual Partitioning
No full textThe need for a change in view of a sustainable energy transition is introducing novel challenges in many fields such as power production, transmission, distribution and utilization. On the user side, defining new strategies to reach energy neutrality and sustainability is an important step in this process. This paper proposes a novel Virtual Partitioning Algorithm (VPA) for Electric Vehicles (EVs) energy storage system to provide vehicles-to-home (V2H) services in a novel and effective manner. The VPA will improve the environmental and economic performance of prosumers with residential photovoltaic or other renewable energy systems by exploiting the energy storage availability of EVs in an effective way. The VPA for V2H services is applied to realistic residential single-family and multi-family housing test cases using real measured data. Results highlight the positive impact of the proposed approach both from an economic and energy sustainability point of view
Can Frequency Be Used to Achieve Communication-Less Primary Control in Photovoltaic-Storage Islanded Microgrids?
No full textIn the new energy scenario Renewable Energy Sources are playing a central role especially if energy islands are concerned. In particular, energy islands without synchronous generation, for example photovoltaic storage, are of major interest if one aims at a sustainable transition of these systems. In this Microgrid structure Grid-Forming and Grid-Feeding inverters need to be properly managed in order to cope with the features usually provided by the main power grid, i.e. frequency and voltage regulation. This paper wants to provide an analytical demonstration that even in no-inertia islands, the system frequency is still a suitable signal to provide frequency regulation and thus to guarantee the power balance and primary frequency regulation without any need of additional communication among generating units
Electric Vehicle Battery Virtual Partitioning Algorithm for Residential Vehicle-to-Home Service
No full textThe current trend of electrification and transition to a sustainable and resilient electricity energy scenario is introducing new challenges and necessary improvements on the generation, transmission, distribution and end-user side. These changes require introducing novel solutions to exploit at maximum the potentials of the ongoing electrification of several sectors, especially at customer level. This paper proposes a novel Virtual Partitioning Algorithm (VPA) dedicated to vehicles-to-home (V2H) service provided by private Electric Vehicles (EVs). The VPA will allow improving the environmental and economic performance of prosumers that have residential photovoltaic plants without the need of installing dedicated flexibility devices, e.g. battery energy storage systems (ST), or integrating existing storage units to expand the overall capacity without additional costs. This will help moving in the direction of a more sustainable energy scenario for buildings and energy systems also in the frame of novel configuration such as renewable energy communities. The proposed solution has been tested in a realistic residential setup with real data and the results highlighted the benefits from both the system integration and economic side
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Design and Implementation of a Variable Synthetic Inertia Controller for Wind Turbine Generators
No full textThe increasing penetration of Renewable Energy Sources (RES) and, more in general, of converter connected power generation is progressively reducing the overall inertia of the electricity system introducing new challenges in the network Frequency Support (FS). Therefore, FS strategies for RES are becoming an important aspect to be developed in order to ensure the secure operation of the electricity power grid. The aim of the present article is to propose an innovative approach for the inertial emulation of Wind Turbine Generators (WTGs) in order to ensure a positive effect on the system frequency avoiding unstable operations of the WTG and reducing the negative impact of the rotor speed recovery on the secondary frequency drop. Moreover, the paper provides a detailed definition of the triggering logics adopted to activate and deactivate the FS making it suitable for implementation in available industrial controllers. The proposed controller is firstly tested on a simplified configuration to show its enhanced performances with respect to previously developed approaches. Then, simulations are carried out in a more realistic network to assess the positive impact of the controller on the system frequency. Results highlighted a 40% reduction of the system Rate of Change of Frequency while the frequency deviation at the transient nadir is improved by 35%
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