Search results for "Discharges"

Space Charges and Partial Discharges Simultaneous Measurements under DC Stress

2016

In the field of HVDC, the main causes of insulation aging are due to the space charge and PD phenomena. In particular, the purpose of the present work is to verify a possibility to measure simultaneously the space charge and the PDs under DC stress in order to evaluate the correlation between both phenomena. The space charge was measured by using a modified PEA cell and PDs were measured by using a novel wireless sensor system. The space charge profile and the PD pulses carried out simultaneously have been reported and discussed.

Critical issues in the PD testing methodology for XLPE-insulated MV cables: An experimental case

2017

This paper describes some critical issues arising during the partial discharge (PD) testing of a 500m delivery length of an XLPE-insulated MV cable. At first, conventional PD measurements were performed on the whole length by using a standard acquisition system; PDs activity was detected, but the system allowed the operator to localize the PDs only on a length of 70 m. A visual inspection of this section highlighted the presence of an excoriation in the outer sheet. Aiming at a more accurate pin-pointing of the defect, more measurements were carried out in the proximity of the outer defect using a portable PD detection system. These measurements showed PDs activity, whose source was located…

Estimating ion confinement times from beam current transients in conventional and charge breeder ECRIS

2019

International audience; Cumulative ion confinement times are probed by measuring decaying ion current transients in pulsed material injection mode. The method is applied in a charge breeder and conventional ECRIS yielding mutually corroborative results. The cumulative confinement time estimates vary from approximately 2 ms–60 ms with a clear dependence on the ion charge-to-mass ratio—higher charges having longer residence times. The long cumulative confinement times are proposed as a partial explanation to recently observed unexpectedly high ion temperatures. The results are relevant for rare ion beam (RIB) production as the confinement time and the lifetime of stable isotopes can be used f…

Latency of interictal epileptiform discharges in long-term EEG recordings in epilepsy patients.

2015

AbstractPurposeTo assess the latency of interictal epileptiform discharges (IED) and seizures in long-term EEG recordings of patients with epilepsy.MethodIED latency was measured in 210 consecutive patients (mean (SD) age 38.6±13.9 years) with active epilepsy and the relationship to clinical variables was analyzed retrospectively. Median duration of EEG recording was 101.5h (95% confidence interval [CI] 92 to 117h).ResultsIEDs were absent in 45 (21.4%) and present in 165 (78.6%) patients who had a longer duration (p<0.001) and early onset (p<0.01) of epilepsy and more often had IEDs in prior standard EEGs (p<0.01), a structural etiology (OR 2.4, CI: 2.1–2.7), or temporal lobe epilepsy (OR 9…

International Legal Approaches to Waste Water Discharges

2002

Este capítulo se dedica al estudio de los distintos enfoques jurídicos seguidos en el Derecho Internacional del Medio Ambiente sobre las descargas de aguas residuales. Comienza analizando los enfoques jurídicos fragmentarios iniciales sobre las descargas de aguas residuales, principalmente en la Antártida y el Océano Austral, en algunos mares regionales (especialmente, el Mediterráneo) y el caso particular de las descargas de basuras procedentes de buques. No obstante, dedico la parte principal de este capítulo al enfoque global que sobre esta cuestión clave de la contaminación marina se inició en 1995, así como a su aplicación jurídica global, regional y nacional. This chapter is devoted t…

Global Frequency and Geographical Distribution of Nighttime Streamer Corona Discharges (BLUEs) in Thunderclouds

2021

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Marine Discharges of Offshore Produced Water: the North-East Atlantic Management Strategy

2002

Este capítulo contiene un estudio de Derecho internacional del medio ambiente sobre las normas y estrategias para prevenir y eliminar la contaminación resultante de hidrocarburos y otras substancias causadas por las descargas de agua de producción costa afuera en el mar. Debemos tener en cuenta que no existe ni un solo tratado internacional de ámbito mundial relativo a la contaminación por descargas de hidrocarburos contenidas en las aguas de producción generadas en las instalaciones costa afuera. De hecho, sólo hay una región marina donde existen normas jurídicas y estrategias para hacer frente a este problema de contaminación. La región marina es el Atlántico nordeste y la norma en cuesti…

Electrical Aging Tests on Enameled Wire Exposed to Gamma Irradiation

2011

A set of indicators for arc faults detection based on low frequency harmonic analysis

2016

In this paper a novel set of indicators is presented for arc faults detection in electrical circuits. The indicators are defined starting from an experimental characterization of the arc fault phenomenon and the study of the arcing current in several test conditions, which were chosen in accordance with the UL 1699 Standard requirements. The proposed parameters are measured by means of a high resolution low frequency spectral analysis of the arcing current, which allows to achieve a good spectral resolution even with short observation windows.

A portable instrument for the location and identification of defects generating PD

2011

A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…