1,721,021 research outputs found
Impact analysis of PV and PEV integration with a non-synthetic european LV test system
No full textIn this paper, the reasons behind the necessity for accurate and reliable test systems for network analysis are addressed, and the almost total absence of representative models for the European LV network is considered. Further, the possibility to exploit non-synthetic electric and geographical data, to build real networks is debated, along with a thorough demonstration of the potential in the work by Koirala et al. to prove the versatility of the tool - which also allows modular implementation of synthetic data - an altered version of the Non-Synthetic European Low Voltage Test System is developed. Distributed photovoltaic (PV) generation and plug-in electric vehicle (PEV) representative loads are integrated in a daily time series power flow analysis for different penetration levels. The results obtained from the stress test comply with the assertions of prior studies, with some exceptions. A moderated PV implementation - up to around 40% of the base energy absorption - is possible for appropriate voltage management, and widely improves the energy conditions, whilst PEV contributions to the load cannot be reduced because of mismatch. Furthermore, the research demonstrates that LV network capability to accommodate PV penetration is inversely proportional to PEV contribution to the load. To facilitate penetration, the implementation of regulation controls within the grid should be evaluated. Finally, concerns regarding power and voltage daily rate of change in the presence of high PV and PEV penetration are raised
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
Integration of Process-Side Energy Storage and Active Distribution Networks: Technical and Economical Optimisation
No full textThis paper is primarily aimed at demonstrating how
energy tariffs with a significant price difference between
day and night can make energy storage systems more
profitable for an active customer. An optimisation
procedure, based on the “energy hub” concept, has been
devised and applied for a coordinated operation of local
generation and process-side electric and thermal
storages. The optimized integrated management of these
systems enables an efficient use of primary sources,
largely resorting to co-generation (CHP) and an optimal
use of production and storage devices. Different case
studies show how supply and distribution tariffs can
influence the cost-effective operation of a CHP system,
assuming the presence of various kinds of process-side
storages
Centralized OPF in Unbalanced Multi-Phase Neutral Equipped Distribution Networks Hosting ZIP Loads
Full text linkOptimal Dispatch of PV Inverters in Multi-Phase Low Voltage Active Distribution Networks
No full textA novel optimal PhotoVoltaic (PV) inverter dispatch scheme is proposed in this paper which combines the active power curtailment and reactive power control schemes in order to simultaneously determine the optimal active and reactive power set points of residential PVs. The non-convexity of resultant AC optimal power flow model, caused by the inherent power balance constraints and selective inclusion of PV systems through binary variables, is handled by leveraging the cheap semi-definiteprogramming and sparsity-promoting-regularization approaches. The application of proposed methodology on a low-voltage test distribution network shows that recurrent technical issues of these networks such as voltage rise and voltage unbalance can be successfully mitigated as well as significant reduction in active power losses can also be achieved
Convexified OPF in Multiphase Low Voltage Radial Distribution Networks including Neutral Conductor
No full textThe pilot projects for the development of Smart Grids [I progetti pilota per lo sviluppo delle Smart Grids]
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