RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS

Introduction. The presence of free moisture in power cables leading to the formation of tree structures - water treeing, which originate in the amorphous phase polyethylene and are a major cause of degradation of the polymer insulation. They represent the damage of the polymer size from several micr...

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Autores principales:	G.V. Bezprozvannych, A.G. Kyessayev
Formato:	article
Lenguaje:	EN RU UK
Publicado:	National Technical University "Kharkiv Polytechnic Institute" 2016
Materias:	water treeing moisturizing cables solid and foamed polyethylene insulation dielectric loss tangent water clusters relaxation peaks Electrical engineering. Electronics. Nuclear engineering TK1-9971
Acceso en línea:	https://doaj.org/article/d18b71cf09364851baddd055f3e4e3c7
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spelling	oai:doaj.org-article:d18b71cf09364851baddd055f3e4e3c72021-12-02T17:56:19ZRELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS10.20998/2074-272X.2016.2.072074-272X2309-3404https://doaj.org/article/d18b71cf09364851baddd055f3e4e3c72016-05-01T00:00:00Zhttp://eie.khpi.edu.ua/article/view/2074-272X.2016.2.07/64347https://doaj.org/toc/2074-272Xhttps://doaj.org/toc/2309-3404Introduction. The presence of free moisture in power cables leading to the formation of tree structures - water treeing, which originate in the amorphous phase polyethylene and are a major cause of degradation of the polymer insulation. They represent the damage of the polymer size from several microns to 1 mm, developing technology for insulation defects under the combined action of the electric field and the moisture diffusing from the environment. Water treeing destroys the polymer chain, resulting in the formation of microcavities filled with moisture. The dynamics of water treeing and subtle properties largely depend on the composition, morphology of the polymer insulation, chemical nature of the defect, in which they originate. Due to the force of gravity in the water formed typical only for her region with locally ordered structure - clusters, which cause loss of relaxation. Purpose. Features presence of relaxation losses in high-frequency range in polyethylene insulation during aging in high humidity conditions of samples power and RF cables. Methodology. Samples of the power cable for the voltage of 35 kV with a cross-linked polyethylene insulation radial water-blocking protection from moisture and radio-frequency coaxial cable with thermoplastic insulation for 1440 hours in a humidity of 100%. The dielectric loss tangent measured resonance method before and after aging. Originality. Experimentally found evidence of the existence in the polymer cable insulation free water in the form of areas with locally ordered structure - clusters. It is found that the solid polyethylene insulation in the frequency dependence of dielectric loss tangent maximum relaxation shown one at 10 MHz in the initial state, and there are two additional frequency range 500 kHz - 5 MHz after moistening. For cross-linked polyethylene insulation characteristic of large width Δf of the frequency spectrum in which the observed relaxation losses. It is obvious that the width of each of the relaxation maxima is associated with characteristic fractal cluster size. It is important that the hydrated solid and foamed polyethylene insulation to show individuality, typical only for water clusters which are detected by high-frequency dipole relaxation peaks dielectric loss tangent. There is a positive correlation between the bandwidth Δf of relaxation maxima and the rate of decrease of insulation resistance by applying a high DC voltage. Practical value. Establishing a correlation between the bandwidth of relaxation maxima and the rate of decrease in the insulation resistance test objects in the laboratory makes it possible to diagnose the presence of free moisture in the power and RF cables by measuring the insulation resistance in exploitation.G.V. BezprozvannychA.G. KyessayevNational Technical University "Kharkiv Polytechnic Institute"articlewater treeingmoisturizing cablessolid and foamed polyethylene insulationdielectric loss tangentwater clustersrelaxation peaksElectrical engineering. Electronics. Nuclear engineeringTK1-9971ENRUUKElectrical engineering & Electromechanics, Iss 2, Pp 38-42 (2016)
institution	DOAJ
collection	DOAJ
language	EN RU UK
topic	water treeing moisturizing cables solid and foamed polyethylene insulation dielectric loss tangent water clusters relaxation peaks Electrical engineering. Electronics. Nuclear engineering TK1-9971
spellingShingle	water treeing moisturizing cables solid and foamed polyethylene insulation dielectric loss tangent water clusters relaxation peaks Electrical engineering. Electronics. Nuclear engineering TK1-9971 G.V. Bezprozvannych A.G. Kyessayev RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
description	Introduction. The presence of free moisture in power cables leading to the formation of tree structures - water treeing, which originate in the amorphous phase polyethylene and are a major cause of degradation of the polymer insulation. They represent the damage of the polymer size from several microns to 1 mm, developing technology for insulation defects under the combined action of the electric field and the moisture diffusing from the environment. Water treeing destroys the polymer chain, resulting in the formation of microcavities filled with moisture. The dynamics of water treeing and subtle properties largely depend on the composition, morphology of the polymer insulation, chemical nature of the defect, in which they originate. Due to the force of gravity in the water formed typical only for her region with locally ordered structure - clusters, which cause loss of relaxation. Purpose. Features presence of relaxation losses in high-frequency range in polyethylene insulation during aging in high humidity conditions of samples power and RF cables. Methodology. Samples of the power cable for the voltage of 35 kV with a cross-linked polyethylene insulation radial water-blocking protection from moisture and radio-frequency coaxial cable with thermoplastic insulation for 1440 hours in a humidity of 100%. The dielectric loss tangent measured resonance method before and after aging. Originality. Experimentally found evidence of the existence in the polymer cable insulation free water in the form of areas with locally ordered structure - clusters. It is found that the solid polyethylene insulation in the frequency dependence of dielectric loss tangent maximum relaxation shown one at 10 MHz in the initial state, and there are two additional frequency range 500 kHz - 5 MHz after moistening. For cross-linked polyethylene insulation characteristic of large width Δf of the frequency spectrum in which the observed relaxation losses. It is obvious that the width of each of the relaxation maxima is associated with characteristic fractal cluster size. It is important that the hydrated solid and foamed polyethylene insulation to show individuality, typical only for water clusters which are detected by high-frequency dipole relaxation peaks dielectric loss tangent. There is a positive correlation between the bandwidth Δf of relaxation maxima and the rate of decrease of insulation resistance by applying a high DC voltage. Practical value. Establishing a correlation between the bandwidth of relaxation maxima and the rate of decrease in the insulation resistance test objects in the laboratory makes it possible to diagnose the presence of free moisture in the power and RF cables by measuring the insulation resistance in exploitation.
format	article
author	G.V. Bezprozvannych A.G. Kyessayev
author_facet	G.V. Bezprozvannych A.G. Kyessayev
author_sort	G.V. Bezprozvannych
title	RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
title_short	RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
title_full	RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
title_fullStr	RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
title_full_unstemmed	RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS
title_sort	relaxations losses in polyethylene insulation of coaxial cable structure during aging in high humidity conditions
publisher	National Technical University "Kharkiv Polytechnic Institute"
publishDate	2016
url	https://doaj.org/article/d18b71cf09364851baddd055f3e4e3c7
work_keys_str_mv	AT gvbezprozvannych relaxationslossesinpolyethyleneinsulationofcoaxialcablestructureduringaginginhighhumidityconditions AT agkyessayev relaxationslossesinpolyethyleneinsulationofcoaxialcablestructureduringaginginhighhumidityconditions
_version_	1718379074287566848

RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS

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