1,720,989 research outputs found
Operating envelopes of the Malta-Sicily 245 KV-50 HZ cable
No full textThe Malta-Sicily 245 kV-50 Hz interconnector will be the longest HVAC cable in the world, delivering up to 225 MW over a single 3-core cable. Reactive power support to the Maltese network is also possible, using a variable, asymmetric shunt compensation scheme. © 2012 IEEE
Frequency domain studies for the Malta-Sicily interconnector
No full textVery long HV and EHV submarine ac cable lines can be an effective solution for bulk power transmission systems at distances up to 100 km, as demonstrated by several recent projects like the Malta-Sicily and the Mallorca-Ibiza interconnections. However the introduction of very long HV cable system can cause significant interaction between the existing network and the cable system itself. Most recent literature focuses about two main issues:
• Switching transients, mainly due to the distributed nature of the line.
• Low-order harmonic resonances, mainly due to the interaction of the cable capacitance with the (inductive) network impedance.
Even if the first issue could be counteracted by proper selection of line-end surge arresters (SAs), the latter could result in temporary overvoltages, typically as a consequence of switching manoeuvres, especially troublesome to above mentioned SAs. The relative weakness of one or both interconnected networks, in terms of short circuit current, exacerbates the above issues; very long cable lines connecting weak nodes (such as offshore windfarms or small isolated networks) should thus be investigated by means of time and frequency domain studies, also due to the current lack of information about operating results of similar projects, most of which are presently under construction.
The paper deals with the detailed frequency domain studies for the 118 km Malta-Sicily line, which will be the longest 245 kV cable in the world
EHV ac interconnection for a GW-size offshore wind-farm cluster: preliminary sizing
No full textThe recent availability of XLPE-insulated, 400 kV-50 Hz submarine cables, in single- or three-core construction, suggests to investigate the ac shore connection of GW-sized offshore wind-farm (OWF) clusters. The paper discusses some basic features of a 200 km long 400 kV-50 Hz cable system, connecting to the grid three large OWFs with 2 GW total capacity. After selecting suitable cables based on their active power transfer capacity, a shunt compensation plan for the resulting system is proposed, taking into account maximum exploitation of the longest cable stretch as well as no-load system operation. A simple but effective approximate algorithm for the optimal exploitation of the cable system by OWF voltage control is proposed; simulations show the viability of the interconnector and of the proposed algorithm for several different loading conditions. Results evidence good steady-state performances, with small reactive surplus and, notably, full-load losses not exceeding 3%
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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