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Effect of Cooling Medium on LDPE Dielectric Properties

Polyethylene, with its excellent mechanical and dielectric properties is used as an insulator for high-voltage direct current (HVDC) transmission. In ultra-high-voltage direct current (UHVDC) transmission, the ageing of insulation materials caused by space charge under high DC voltage becomes seriou...

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Autores principales: Cheng, Yujia, Yu, Guang, Duan, Zhuohua
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838216/
https://www.ncbi.nlm.nih.gov/pubmed/35160415
http://dx.doi.org/10.3390/polym14030425
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author Cheng, Yujia
Yu, Guang
Duan, Zhuohua
author_facet Cheng, Yujia
Yu, Guang
Duan, Zhuohua
author_sort Cheng, Yujia
collection PubMed
description Polyethylene, with its excellent mechanical and dielectric properties is used as an insulator for high-voltage direct current (HVDC) transmission. In ultra-high-voltage direct current (UHVDC) transmission, the ageing of insulation materials caused by space charge under high DC voltage becomes serious. Therefore, restraining the space charge and improving the dielectric properties of HVDC cables is important. In this study, low-density polyethylene (LDPE) was used as the raw material and combined with cooling media in a vulcanizing press. A polarizing microscope was used to observe the samples’ crystal morphologies. The space charge accumulation and dispersion were detected using pulsed electro-acoustic. Additionally, dielectric properties such as electrical conductivity and dielectric frequency spectrum were tested. The grain size in the air-cooled LDPE samples was found to be large and unevenly dispersed. However, the grain sizes in the water and oil cooling LDPE samples were small. The mean charge density of the oil cooling samples was the lowest. Under a short circuit measurement, more space charges were found in the natural and rapid air cooling samples. The mean charge densities of these two samples were high, with a fast decay rate. With an 8 and 50 kV/mm electric field strength, the oil cooling samples’ conductivity was the highest and lowest, respectively.
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spelling pubmed-88382162022-02-13 Effect of Cooling Medium on LDPE Dielectric Properties Cheng, Yujia Yu, Guang Duan, Zhuohua Polymers (Basel) Article Polyethylene, with its excellent mechanical and dielectric properties is used as an insulator for high-voltage direct current (HVDC) transmission. In ultra-high-voltage direct current (UHVDC) transmission, the ageing of insulation materials caused by space charge under high DC voltage becomes serious. Therefore, restraining the space charge and improving the dielectric properties of HVDC cables is important. In this study, low-density polyethylene (LDPE) was used as the raw material and combined with cooling media in a vulcanizing press. A polarizing microscope was used to observe the samples’ crystal morphologies. The space charge accumulation and dispersion were detected using pulsed electro-acoustic. Additionally, dielectric properties such as electrical conductivity and dielectric frequency spectrum were tested. The grain size in the air-cooled LDPE samples was found to be large and unevenly dispersed. However, the grain sizes in the water and oil cooling LDPE samples were small. The mean charge density of the oil cooling samples was the lowest. Under a short circuit measurement, more space charges were found in the natural and rapid air cooling samples. The mean charge densities of these two samples were high, with a fast decay rate. With an 8 and 50 kV/mm electric field strength, the oil cooling samples’ conductivity was the highest and lowest, respectively. MDPI 2022-01-21 /pmc/articles/PMC8838216/ /pubmed/35160415 http://dx.doi.org/10.3390/polym14030425 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Cheng, Yujia
Yu, Guang
Duan, Zhuohua
Effect of Cooling Medium on LDPE Dielectric Properties
title Effect of Cooling Medium on LDPE Dielectric Properties
title_full Effect of Cooling Medium on LDPE Dielectric Properties
title_fullStr Effect of Cooling Medium on LDPE Dielectric Properties
title_full_unstemmed Effect of Cooling Medium on LDPE Dielectric Properties
title_short Effect of Cooling Medium on LDPE Dielectric Properties
title_sort effect of cooling medium on ldpe dielectric properties
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838216/
https://www.ncbi.nlm.nih.gov/pubmed/35160415
http://dx.doi.org/10.3390/polym14030425
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