22 research outputs found
Etude des decharges partielles et leurs influences sur l'apparition des arborescenes dans la couche isolante des cables haute tension
Get PDFParameters that influence the partial discharges occurrence in cavity defect within electrical cable insulation
No full textThe electrical cable reliability is largely linked to the state of its insulation, which can be threatened by the partial discharges (PDs) activity. This phenomenon is localized in defects created within insulation during the manufacture process and the cable installation. The cavity defect is among the most known defects within the insulating material filled with different gases and having various forms. Under electrical stress, the PDs occur and lead with time to a cable failure. The PDs simulation in cavity defect within cable insulation has became an important tool for a complementary understanding of the experimental task. The plasma model has been considered in last decade as an alternative to describe physically and chemically the PDs mechanism versus the other models such as the capacitance, conductance model. Using plasma model our work aims to simulate the PDs in cavity defect within cable insulation by showing the parameters influence such as the type of gas contained in the cavity, the voltage magnitude and frequency imposed on the insulation on their occurrence through its occurrence mechanisms. This helps to assess the PDs severity on the insulation system to carry out its diagnosis and therefore to have an effective reliability of cable
Simple matrix representations of the orthogonal polynomials for a rational spectral density on the unit circle
Get PDFIn this note, by using a discrete analog of a projection formula introduced by A. Seghier in 1978, we calculate the orthogonal polynomials on the unit circle for a rational spectral density having no zeros there, and derive simple matrix representations of themselves, their squared norms, and the Verblunsky coefficients. (C) 2018 Elsevier Inc. All rights reserved
Study of the influence of an electromagnetic field close to a high-voltage line on the human being
No full textInduction machine diagnosis of the broken rotor bars based on air-gap magnetic flux density
No full textDynamic Analysis of the Simultaneous Mixed Eccentricity and Broken Rotor Bars in Induction Machine Based on Magnetic Field Diagnosis
No full textDefects rotor identification by magnetic spectrum analyzing in a squirrel-cage asynchronous machine
No full textPrediction the AC Breakdown Voltage in Point/Plane Air Gaps with Barrier Using Design of Experiments
No full textInternational audienceBreakdown voltage characteristics of air gaps considered a random process we have investigated how to find relevant statistical different leading to breakdown or with standing during an impulse voltage test under the same condition for a plane high voltage electrode and a grounded electrode configuration.In the present paper methods of the modelling and prediction of the AC breakdown voltage in point-plane air gaps are investigated. An analysis based on experiments design method has been developed with indicates that. Measurements to contain some relevant information test at early stages in reduced time frame investigation were done on a point-plane with barrier varying in position and size. The barrier used was mounted vertically between the electrodes.The use of methodology of experiments design is one of this methods and present an original idea in high voltage prediction problems several factors were considered,namely the distance between electrodes and different parameters of the barrier such us is dimension and his holes.The experimental results are compared with results from numerical simulations. We firstly present the principals of this model then we apply it to the study of barrier effect.A good agreement has been found between the computed and experimental result
Experimental model investigation of the corrosion of buried steel pipelines with cathodic protection near high voltage power lines
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