1,721,017 research outputs found
Integration of distributed generation in the power system
No full text"The integration of new sources of energy like wind power, solar-power, small-scale generation, or combined heat and power in the power grid is something that impacts a lot of stakeholders: network companies (both distribution and transmission), the owners and operators of the DG units, other end-users of the power grid (including normal consumers like you and me) and not in the least policy makers and regulators. There is a lot of misunderstanding about the impact of DG on the power grid, with one side (including mainly some but certainly not all, network companies) claiming that the lights will go out soon, whereas the other side (including some DG operators and large parks of the general public) claiming that there is nothing to worry about and that it's all a conspiracy of the large production companies that want to protect their own interests and keep the electricity price high. The authors are of the strong opinion that this is NOT the way one should approach such an important subject as the integration of new, more environmentally friendly, sources of energy in the power grid. With this book the authors aim to bring some clarity to the debate allowing all stakeholders together to move to a solution. This book will introduce systematic and transparent methods for quantifying the impact of DG on the power grid"--"Gives a power-system viewpoint contrary to the energy viewpoint presented in many other books on DG Emphasis on systematic and transparent calculation methods allowing a quantification of the amount of DG that can be integrated at a certain location of the grid or in the grid as a whole Provides an overview of the different energy sources, with emphasis on windpower, solar power and CHP (Combined Heat & Power) Provides a general overview of the different methods available to allow more DG to be connected to the grid, ranging from classical methods like building more lines, to advanced methods like power-electronics control, and even future methods like smartgrids and microgrids"-
Understanding power quality problems voltage sags and interruptions
No full text"Power quality problems have increasingly become a substantial concern over the last decade, but surprisingly few analytical techniques have been developed to overcome these disturbances in system-equipment interactions. Now in this comprehensive book, power engineers and students can find the theoretical background necessary for understanding how to analyze, predict, and mitigate the two most severe power disturbances: voltage sags and interruptions. This is the first book to offer in-depth analysis of voltage sags and interruptions and to show how to apply mathematical techniques for practical solutions to these disturbances. From UNDERSTANDING AND SOLVING POWER QUALITY PROBLEMS you will gain important insights into . Various types of power quality phenomena and power quality standards. Current methods for power system reliability evaluation. Origins of voltage sags and interruptions. Essential analysis of voltage sags for characterization and prediction of equipment behavior and stochastic prediction. Mitigation methods against voltage sags and interruptions" An Instructor Support FTP site is available from the Wiley editorial department: ftp://ftp.ieee.org/uploads/press/bollen Sponsored by: IEEE Power Electronics Society, IEEE Industry Applications Society, IEEE Power Engineering Societ
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
Overload and overvoltage in low-voltage and medium-voltage networks due to renewable energy — Some illustrative case studies
No full textThis paper presents the use of curtailment to allowmore wind or solar power to be connected to a distributionnetwork when overcurrent or overvoltage set a limit. For fourcase studies, all based on measurements, the gain in producedenergy is calculated. It is shown that the curtailment method hasa large impact on this gain. The paper further discusses details ofthe curtailment algorithm and the communication needs as wellas some further applications of curtailment.</p
A Stochastic Aggregate Harmonic Load Model
No full textThis article presents a stochastic aggregate harmonic load model that can be used to accurately replicate the stochastic behavior of the network impedance downstream of a point of aggregation. The method has been applied to three low voltage networks and the results show that it is able to accurately represent their stochastic behavior while significantly reducing the computational burden compared to modelling the downstream network in detail.</p
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