1,720,967 research outputs found
Concept Design of a module for reversible HVDC submarine deep-water sea electrodes
No full textOver the last years many HVDC (High Voltage Direct Current) links are being studied, commissioned and built. Among the constraints, one of the most important is the corrosion risk analysis of surrounding submerged/buried metallic structures. If the coastal area is rich of metallic structures, corrosion risk may be unacceptable, and the electrode must be located at greater distance offshore. As seawater at the selected location may be considerably deep, many issues about maintenance and mechanical resistance must be considered, and related problems must be solved. We developed a modular electrode able to cope efficiently with all such requirements
Influence of surge arresters on the statistical evaluation of lightning performance of distribution lines
No full textThe statistical assessment of the lightning-performances of distribution lines must take into account the presence of protection devices such as surge arresters and shielding wire/neutral groundings. Indeed, the presence of those devices does modify the indirect lightning-response of the line. A statistical investigation based on the Monte Carlo method is carried out on a distribution line with realistic configuration, aimed at assessing the indirect lightning-performance of the line. Accurate models are used to evaluate the lightning performance of the line equipped with surge arresters, in order to estimate the effects of arresters spacing and characteristics. A preprocessing procedure based on the simplified Rusck formula for a first evaluation of the lightning-induced voltages of the randomly generated events is implemented in order to reduce the computational time
Demand Side Activities for Improving Power Quality Awareness of Industrial Customers in a Competitive Electricity Market
No full textDemand side activities for improving power quality awareness of industrial customers in a competitive electricity market
No full textThe paper illustrates some activities that are being part of an Italian research program of public interest called “Ricerca di Sistema” investigating the main power quality (PQ) aspects at industrial customers across Italy. In particular two main activities are illustrated in detail: a) a questionnaire based survey aimed at building a knowledge base on industrial power quality with particular concern to the possible origins of power supply anomalies and the possible costs that are typically involved; b) a knowledge-based software tool aimed to support industrial customers in evaluating PQ disturbances impact on their processes
Lightning-Induced Voltages on Overhead Distribution Lines: Theoretical and Experimental Investigation of related Problems and their Impact on Power Quality
No full textRecent power quality studies have been focused on the source-identification of voltage disturbances at distribution network busses. This paper describes a method aimed at correlating indirect-lightning events with power systems relay operations, associated with voltage dips. The proposed method, based on the coordinated use of the Italian lightning location system CESI-SIRF, the Italian monitoring system of protection manoeuvres CESI-SAM, and the availability of an advanced simulation tool for the accurate simulation of lightning-induced voltages on complex power networks, namely the LIOV-EMTP code, is applied to the real case of an Italian distribution system.
The LIOV-EMTP code is also employed along with a statistical procedure based on the Monte Carlo method to carry out a statistical analysis aimed at assessing the lightning performance of a typical Italian distribution line
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
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