scholarly journals Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1333
Author(s):  
Xiangjin Guo ◽  
Zhaoliang Xing ◽  
Shiyi Zhao ◽  
Yingchao Cui ◽  
Guochang Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Space Charge ◽  
Direct Current ◽  
Breakdown Strength ◽  
Charge Carrier Mobility ◽  
Charge Accumulation ◽  
Polyethylene Matrix ◽  
Uniform Size ◽  
Α Al2o3 ◽  
Surface Modified

This paper describes the effects of α-Al2O3 nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al2O3 nanocomposites. The α-Al2O3 nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al2O3 nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al2O3 nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 × 10−13 S/m to 1.04 × 10−13 S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al2O3 nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al2O3 nanocomposites.

Titanium oxide nanoparticle increases shallow traps to suppress space charge accumulation in polypropylene dielectrics

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 48720-48727 ◽  
Author(s):  
Yao Zhou ◽  
Jun Hu ◽  
Bin Dang ◽  
Jinliang He
Keyword(s):  
Charge Carrier ◽  
Space Charge ◽  
Titanium Oxide ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Charge Accumulation ◽  
Oxide Nanoparticle ◽  
Surface Modified ◽  
Shallow Traps

Introduction of surface modified nano-TiO2 increases shallow traps and enhances charge carrier mobility so as to suppress space charge accumulation.

scholarly journals Improved Direct Current Electrical Properties of Crosslinked Polyethylene Modified with the Polar Group Compound

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1624 ◽  
Author(s):  
Chengcheng Zhang ◽  
Jianxin Chang ◽  
Hongyu Zhang ◽  
Chunyang Li ◽  
Hong Zhao
Keyword(s):  
Electrical Properties ◽  
Space Charge ◽  
Functional Groups ◽  
Direct Current ◽  
Breakdown Strength ◽  
Photoelectron Spectra ◽  
Polar Group ◽  
Charge Accumulation ◽  
Scanning Calorimetry ◽  
Polar Functional Groups

To suppress space charge accumulation and improve direct current (DC) electrical properties of insulation materials, crosslinked polyethylene modified with 2-(4-benzoyl-3-hydroxyphenoxy) ethyl acrylate (XLPE/BHEA) containing polar functional groups was prepared by melt blending. The gel content, thermal elongation, tensile strength, elongation at break, elasticity modulus, differential scanning calorimetry (DSC) and X-ray photoelectron spectra (XPS) measurement results demonstrated that the BHEA could slightly enhance the crosslinking of polyethylene (PE) and affect the mechanical properties and crystallization of XLPE, and the BHEA molecule was not easy to precipitate from XLPE after the crosslinking process. XLPE modified with 3.0 phr (parts per hundreds by weight) BHEA could effectively suppress space charge accumulation, reduce DC conduction and improve DC breakdown strength of XLPE at a higher temperature. Deeper traps were introduced in XLPE/BHEA composites due to the polar functional groups in BHEA, which could raise the potential charge injection barrier and reduce the charge carrier number and mobility to suppress space charge accumulation and reduce the conduction current density.

scholarly journals Acetylated SEBS Enhanced DC Insulation Performances of Polyethylene

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1033 ◽  
Author(s):  
Wei Dong ◽  
Xuan Wang ◽  
Zaixing Jiang ◽  
Bo Tian ◽  
Yuguang Liu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Field Strength ◽  
Space Charge ◽  
Aromatic Compounds ◽  
Breakdown Strength ◽  
Charge Accumulation ◽  
New Approach ◽  
Functional Units ◽  
Poly Ethylene ◽  
Accumulation Characteristics

Acetophenone can significantly improve the dielectric properties of polyethylene (PE) insulation materials. However, it easily migrates from the PE due to its poor compatibility with the material, which limits its application. In this paper, the functional units of acetophenone were modified in polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) by an acetylation reaction, and SEBS was used as the carrier to inhibit the migration of acetophenone. The number of functional units in the acetylated SEBS (Ac-SEBS) was measured by 1H NMR and the effect of the acetylation degree of SEBS on its compatibility with PE was studied. Meanwhile, the effects of Ac-SEBS on PE’s direct current (DC) breakdown strength and space charge accumulation characteristics were investigated. It is demonstrated that Ac-SEBS can significantly improve the field strength of the DC breakdown and inhibit the accumulation of space charge in the PE matrix. This work provides a new approach for the application of aromatic compounds as voltage stabilizers in DC insulation cable materials.

scholarly journals Enhanced Insulation Performances of Crosslinked Polyethylene Modified by Chemically Grafting Chloroacetic Acid Allyl Ester

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 592 ◽  
Author(s):  
Xin-Dong Zhao ◽  
Wei-Feng Sun ◽  
Hong Zhao
Keyword(s):  
Space Charge ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Chloroacetic Acid ◽  
Dielectric Materials ◽  
Electrical Insulation ◽  
Polar Group ◽  
Charge Accumulation ◽  
Allyl Ester ◽  
Electrical Insulation Properties

Modified crosslinked polyethylene (XLPE) with appreciably enhanced DC electrical insulation properties has been developed by chemical modification of grafting chloroacetic acid allyl ester (CAAE), exploring the trapping mechanism of charge transport inhibition. The bound state traps deriving from grafted molecule are analyzed by first-principles calculations, in combination with the electrical DC conductivity and dielectric breakdown strength experiments to study the underlying mechanism of improving the electrical insulation properties. In contrast to pure XLPE, the XLPE-graft-CAAE represents significantly suppressed space charge accumulation, increased breakdown strength, and reduced conductivity. The substantial deep traps are generated in XLPE-graft-CAAE molecules by polar group of grafted CAAE and accordingly decrease charge mobility and raise charge injection barrier, consequently suppressing space charge accumulation and charge carrier transport. The well agreement of experiments and quantum mechanics calculations suggests a prospective material modification strategy for achieving high-voltage polymer dielectric materials without nanotechnology difficulties as for nanodielectrics.

scholarly journals Dielectric and Thermal Conductivity of Epoxy Resin Impregnated Nano-h-BN Modified Insulating Paper

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1359 ◽  
Author(s):  
Hongda Yang ◽  
Qingguo Chen ◽  
Xinyu Wang ◽  
Minghe Chi ◽  
Heqian Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Space Charge ◽  
Epoxy Resin ◽  
Direct Current ◽  
Heat Conductivity ◽  
Power Transmission ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Insulating Paper

Epoxy resin-impregnated insulation paper (RIP) composites are used as the inner insulation of dry condenser bushing in the ultra-high voltage direct current (UHVDC) power transmission system. To improve the dielectric properties and heat conductivity of RIP, hexagonal boron nitride (h-BN) nano-flakes are added to the insulation paper at concentrations of 0–50 wt % before impregnation with pure epoxy resin. X-ray diffraction (XRD), scanning electron microscopy (SEM) observations, thermal conductivity as well as the typical dielectric properties of direct current (DC) volume conductivity. DC breakdown strength and space charge characteristics were obtained. The maximum of nano-h-BN modified heat conductivity reach 0.478 W/(m·K), increased by 139% compared with unmodified RIP. The DC breakdown electric field strength of the nano-h-BN modified RIP does not reduce much. The conductivity of nano-h-BN modified is less sensitive to temperature. As well, the space charge is suppressed when the content is 50 wt %. Therefore, the nano-h-BN modified RIP is potentially useful in practical dry DC bushing application.

scholarly journals Enhanced Thermal Conductivity and Dielectric Properties of h-BN/LDPE Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4738
Author(s):  
Lijuan He ◽  
Junji Zeng ◽  
Yuewu Huang ◽  
Xiong Yang ◽  
Dawei Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Space Charge ◽  
Direct Current ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Electrical Equipment ◽  
Electrical Performance ◽  
Suppression Effect ◽  
Thermally Conductive ◽  
Ldpe Composites

Low-density polyethylene (LDPE), as an excellent dielectric insulating material, is widely used in electrical equipment insulation, whereas its low thermal conductivity limits its further development and application. Hexagonal boron nitride (h-BN) filler was introduced into LDPE to tailor the properties of LDPE to make it more suitable for high-voltage direct current (HVDC) cable insulation application. We employed melt blending to prepare h-BN/LDPE thermally conductive composite insulation materials with different contents. We focused on investigating the micromorphology and structure, thermal properties, and electrical properties of h-BN/LDPE composites, and explained the space charge characteristics. The scanning electron microscope (SEM) results indicate that the h-BN filler has good dispersibility in the LDPE at a low loading (less than 3 phr (3 g of micron h-BN particles filled in 100g of LDPE)), as well as no heterogeneous phase formation. The results of thermal conductivity analysis show that the introduction of h-BN filler can significantly improve the thermal conductivity of composites. The thermal conductivity of the composite samples with 10 phr h-BN particles is as high as 0.51 W/(m·K), which is 57% higher than that of pure LDPE. The electrical performance illustrates that h-BN filler doping can significantly inhibit space charge injection and reduce space charge accumulation in LDPE. The interface effect between h-BN and the substrate reduces the carrier mobility, thereby suppressing the injection of charges of the same polarity and increasing the direct-current (DC) breakdown strength. h-BN/LDPE composite doped with 3 phr h-BN particles has excellent space charge suppression effect and high DC breakdown strength, which is 14.3% higher than that of pure LDPE.

scholarly journals Influence of Nanocomposites of LDPE Doped with Nano-MgO by Different Preparing Methods on Its Dielectric Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Wenlong Zhang ◽  
Yajie Dai ◽  
Hong Zhao ◽  
Lidong Zhong
Keyword(s):  
Space Charge ◽  
Applied Field ◽  
Breakdown Strength ◽  
Volume Resistivity ◽  
Charge Accumulation ◽  
Preparation Methods ◽  
Heating Method ◽  
Microwave Assisted ◽  
Microwave Assisted Method ◽  
Better Than

LDPE doped with nano-MgO can effectively suppress the space charge accumulation in the nanocomposite under DC applied field, and this suppression was affected greatly by the prepared nano-MgO particles. In this paper, the influence of nanocomposite of LDPE doped with nano-MgO by using different preparation methods on their space charge, and volume resistivity as well as DC breakdown strength was researched. The results showed that size of nano-MgO prepared by the traditional heating method was about 22.74 nm, while being only about 12.76 nm by the microwave-assisted method. When the nano-MgO content in the composite was 2 wt% by weight, the space charge accumulation in this composite was obviously reduced; meanwhile both the volume resistivity and DC breakdown strength were enhanced. When nano-MgO was prepared by the microwave-assisted method, the electric properties of its LDPE nanocomposite were obviously better than those of nano-MgO prepared by traditional heating method.

scholarly journals Functionalization of Silica Nanoparticles to Improve Crosslinking Degree, Insulation Performance and Space Charge Characteristics of UV-initiated XLPE

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3794
Author(s):  
Yu-Wei Fu ◽  
Yong-Qi Zhang ◽  
Wei-Feng Sun ◽  
Xuan Wang
Keyword(s):  
Space Charge ◽  
Silica Nanoparticles ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
High Dispersion ◽  
Polyethylene Matrix ◽  
Crosslinking Degree ◽  
Developed Surface ◽  
High Efficient ◽  
Insulation Performance

In order to inhibit the outward-migrations of photo-initiator molecules in the ultraviolet-initiated crosslinking process and simultaneously improve the crosslinking degree and dielectric properties of crosslinked polyethylene (XLPE) materials, we have specifically developed surface-modified-SiO2/XLPE nanocomposites with the silica nanofillers that have been functionalized through chemical surface modifications. With the sulfur-containing silanes and 3-mercaptopropyl trimethoxy silane (MPTMS), the functional monomers of auxiliary crosslinker triallyl isocyanurate (TAIC) have been successfully grafted on the silica surface through thiol–ene click chemistry reactions. The grafted functional groups are verified by molecular characterizations of Fourier transform infrared spectra and nuclear magnetic resonance hydrogen spectra. Scanning electronic microscopy (SEM) indicates that the functionalized silica nanoparticles have been filled into polyethylene matrix with remarkably increased dispersivity compared with the neat silica nanoparticles. Under ultraviolet (UV) irradiation, the high efficient crosslinking reactions of polyethylene molecules are facilitated by the auxiliary crosslinkers that have been grafted onto the surfaces of silica nanofillers in polyethylene matrix. With the UV-initiated crosslinking technique, the crosslinking degree, insulation performance, and space charge characteristics of SiO2/XLPE nanocomposites are investigated in comparison with the XLPE material. Due to the combined effects of the high dispersion of nanofillers and the polar-groups of TAIC grafted on the surfaces of SiO2 nanofillers, the functionlized-SiO2/XLPE nanocomposite with an appropriate filling content represents the most preferable crosslinking degree with multiple improvements in the space charge characteristics and direct current dielectric breakdown strength. Simultaneously employing nanodielectric technology and functional-group surface modification, this study promises a modification strategy for developing XLPE nanocomposites with high mechanical and dielectric performances.

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