1,720,960 research outputs found
Valutazioni sulla stabilità di frequenza e sui requisiti di inerzia e potenza di cortocircuito nel sistema elettrico italiano: modelli e strumenti integrati
Full text linkThe energy transition involves a widespread adoption of renewable generation and the simultaneous reduction of thermoelectric generation. This implies a decrease in the resources for frequency regulation, inertia and short-circuit power, to be compensated by other resources and solutions. Adequacy assessment of the flexibility resources for power system stability is therefore essential. The report presents three
activities about this topic.
The first activity concerns the updating of a tool aimed at the mono-zone (based on one-busbar equivalent) adequacy assessment of resources for conventional (“slow”: primary, secondary and tertiary) frequency regulation and for short-circuit power provision. The tool has been updated for multizonal analyses of the active power reserve and has been prepared for multizonal developments concerning the short-circuit power. The application to a 2030 national scenario has shown potential criticalities in the fulfilment of secondary and tertiary reserve requirements, related to the scarcity of thermoelectric generation on the basis of significant decarbonization assumptions.
The second activity concerns the evolution of the “SeTA” procedure (Innovative Services: Automatic Tuning) for the optimization of ultra-fast frequency regulation services. A new iterative approach has been implemented to improve the accuracy in identifying equivalent output-error models of the electrical system which are used for sizing the necessary regulating quantities. The new approach considers, already in the identification phase, the contribution of innovative regulations. Application to a 2030 Sardinian scenario highlights that fast-primary regulation is essential. A contribution of synthetic inertia proves necessary in case of non-implementation of the three new synchronous compensators that are indeed planned.
The third activity concerns the definition of specifications for a platform dedicated to the integrated analysis of slow and ultra-fast frequency regulation resources. Considering the developments achieved in the calculation procedures described above, automating the acquisition of the market simulation results, preliminary to the flexibility analyses, is deemed a priority
Grid-Forming Operation of the HVDC Tyrrhenian Link-East for Improved Frequency Transients
No full textThe paper examines the possibility of operating the VSC (Voltage Source Converter)-based HVDC (High Voltage Direct Current) Tyrrhenian Link-East with grid-forming capabil-ities. The investigations are focused on the frequency transients, and on the possible contribution which can be provided by the Tyrrhenian Link-East to the system. This infrastructure has a strategic importance, and it is designed to support the energy transition enabling a greater integration of renewable energy sources. The dynamic analysis is performed on a simplified 10-bus simulation model of the continental Italian transmission system linked to an equivalent Sicilian network, and it examines different types of contingencies. The results preliminarily suggest that the Tyrrhenian Link-East can effectively contribute to the frequency control of the system, and that the grid-forming capability represents a valid opportunity for the operation of the VSC-HVDC converters of the link
Power system dynamic analysis in future energy scenarios with high penetration of renewable energy sources — case study: Sicilian electrical grid
No full textIn the near future, Sicily will undergo an unprecedented penetration of renewable sources in its electricity generation mix. In response to these developments, several grid enhancement initiatives have been planned, including HVDC infrastructure and interconnections with foreign systems. This paper presents the results of dynamic studies on 2030 energy scenarios developed by the Italian institute Ricerca Sistema Energetico (RSE). These studies consider severe contingencies and evaluate various combinations of regulating resources, both traditional and innovative, including Grid Forming control. The results indicate that relying solely on traditional regulation during contingencies leads to instability, emphasizing the urgent need to involve all available resources in the power system's regulation mechanisms. Among the most interesting findings is the case of the Grid Forming control applied to the Tyrrhenian Link: even in the absence of regulation from the renewable sources present on the island, this approach successfully keeps the frequency drift within the permissible 1.5 Hz range. This demonstrates the significant strategic value of the infrastructure when deployed to provide dynamic support to the power system
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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