Search results for "cables"
showing 10 items of 27 documents
Paesaggi digitali: le manifestazioni spaziali delle tecnologie dell’informazione e della comunicazione
2020
The paper aims to investigate the evolution of the relationship between digital technologies and physical reality, through observing the main spatial manifestations of digital information and communication technologies. In the last decades, the flow of digital information began to materialize itself in a very physical infrastructure made of transcontinental cables and data centers. The analysis revealed the growing environmental and geopolitical implications of digital technologies.
Influence of axial force and corrosion on failure of prestressed concrete structures considering M-V interaction
2021
Abstract Existing prestressed concrete structures suffer from degradation of prestressing for two main reasons: a defect of the sheath infills (cement grout) of bonded tendons, and corrosion of steel strands. These two causes, often concomitant, lead to a reduction over time of the effectiveness of initial prestressing, in addition to the ordinary tension losses due to concrete shrinkage and creep, and to steel relaxation. In many cases a consequence of bad grouting in bonded tendons is that the structure shows an intermediate behavior between that of external prestressing and that of internal bonded prestressing. This, added to damage to wires due to corrosion, makes it essential for the d…
Effect of Heat Exchange Transient Conditions with Moving Water-Air Interface on Space Charge Accumulation in Undersea HVdc Cables
2021
The accumulation of space charge inside the dielectric layer of an HVdc cable is one of the most important issue to be considered in the design stage and during the operating conditions. The separation of space charge is due to several factors including the dependence on temperature of the electrical conductivity of the insulation and the establishment of a thermal gradient under load conditions. This article is focused on the investigation of the effect of an axial heat transmission on the space charge and electric field distributions in an HVdc cable. In order to assess the impact of this phenomenon, a case study involving a cable immersed partly in water and partly in air has been simula…
ANTARES: The first undersea neutrino telescope
2011
The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. © 2011 Elsevier B.V. All rights reserved.
Safety Concerns on Ground Fault Application Transfer Phenomenon in HV Installations
2007
When a fault to ground occurs in HV/MV substations supplied by a combined overhead-cable line, most of the fault current can be transferred and injected into the soil several kilometers far away from the fault location. This phenomenon is called "fault application transfer" and mostly concerns transition stations, where cables are connected to the overhead line. If the transition station is a dead-end steel pole structure, usually accessible to the general public, the local ground electrode could be inadequate to maintain ground potential rise within safety limits. Hence, dangerous touch and step voltages may appear at exposed locations. In the paper results of various computer simulations …
Laboratori de Química Física II
2020
El document forma part dels materials docents programats mitjançant l'ajut del Servei de Política Lingüística de la Universitat de València El “Laboratori de química física II” és una assignatura obligatòria que s’imparteix en el segon quatrimestre durant el tercer curs del grau en Química. És un laboratori que fa èmfasi en l’experimentació en termodinàmica química d’interfases, espectroscòpia, electroquímica, fotoquímica, química quàntica i cinètica química. En el laboratori s’apliquen diverses tècniques instrumentals a l’estudi de sistemes d’interès quimicofísic i s’utilitzen ordinadors per a l’estudi d’àtoms i molècules.
Concrete arch bridges erected by suspended cantilever method vs cable–stayed bridges
2011
A Model for Assessing the Magnitude and Distribution of Sheath Currents in Medium and High-Voltage Cable Lines
2020
In this article, the authors discuss a simulation model to study the effect of cross-bonding of metallic sheaths, and/or nonmagnetic armors, of single-core medium- and high-voltage cables in the same circuit. In single-core cables, the resistive losses due to the induced circulating currents in cable sheaths or armors cause an increase of the cable temperature, which therefore reduces its ampacity. This is a serious issue affecting the distribution and transmission lines. In addition, the risk of electric shock due to induced voltages may be present if a person is in contact with the armor/sheath at its unbounded end. For these reasons, special bonding techniques of metal sheaths are employ…
Sécurité juridique et relations commerciales internationales
2006
Colloque des 26 et 27 octobre 2006; National audience
PCB-Based Planar Inductive Loops for Partial Discharges Detection in Power Cables
2022
Partial discharge (PD) diagnosis tests, including detecting, locating, and identifying, are used to trace defects or faults and assess the degree of aging in order to monitor the insulation condition of medium- and high-voltage power cables. In this context, an experimental evaluation of three different printed circuit board (PCB)-based inductive sensor topologies, with spiral, non-spiral, and meander shapes, is performed. The aim is to assess their capabilities for PD detection along a transmission power cable. First, simulation and experimental characterization are carried out to determine the equivalent electrical circuit and the quality factor of the three sensors. PD activity was studi…