scholarly journals Enhanced High-Temperature DC Dielectric Performance of Crosslinked Polyethylene with a Polystyrene Pinning Structure

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1234 ◽  
Author(s):  
Liang Cao ◽  
Lisheng Zhong ◽  
Yinge Li ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
Direct Current ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Crosslinking Agent ◽  
Special Design ◽  
Insulation Materials ◽  
High Voltage Direct Current ◽  
Dielectric Performance ◽  
Test Temperature Range

In this paper, we propose a method on improving direct current (DC) dielectric performance by designing a polystyrene (PS) pinning crosslinked polyethylene (XLPE) for the application of insulation materials on high voltage direct current (HVDC) extruded cable. Electrical experimental results show that the addition of PS (1–5 phr, parts per hundreds of resin) can significantly reduce DC conductivity and increase DC breakdown strength of XLPE in the test temperature range of 30–90 °C. Microstructure investigation shows PS distributed as particles could participate in the formation of a crosslinking network with the help of a crosslinking agent, thus forming a polymer pinning structure at the interface between XLPE and PS. It is believed that such a special design strengthens the structure of XLPE, which leads to the improved DC dielectric performance at elevated temperatures. Our findings may contribute a new solution for developing HVDC cable insulation materials.

scholarly journals Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1922 ◽  
Author(s):  
Lunzhi Li ◽  
Lisheng Zhong ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
Man Xu
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Insulation Material ◽  
Cable Insulation ◽  
Polyethylene Blends

There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability.

Space charge phenomena in oil-paper insulation materials under high voltage direct current

2009 ◽  
Vol 67 (2-3) ◽  
pp. 417-421 ◽  
Author(s):  
Yuanxiang Zhou ◽  
Yunshan Wang ◽  
Guangfan Li ◽  
Ninghua Wang ◽  
Yingyan Liu ◽  
...  
Keyword(s):  
Space Charge ◽  
High Voltage ◽  
Direct Current ◽  
Insulation Materials ◽  
High Voltage Direct Current ◽  
Paper Insulation

scholarly journals Improving the Thermal Stability of Hydrophobic Associative Polymer Aqueous Solution Using a “Triple-Protection” Strategy

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 949 ◽  
Author(s):  
Bo Yang ◽  
Jincheng Mao ◽  
Jinzhou Zhao ◽  
Yang Shao ◽  
Yang Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Polymer Network ◽  
Crosslinking Agent ◽  
Water Soluble ◽  
Fluid Viscosity ◽  
Fracturing Fluid ◽  
Temperature Resistance ◽  
Protection Strategy

Because of their high viscoelasticity, Hydrophobic Associative Water-Soluble Polymers (HAWSPs) have been widely used in many industrial fields, especially in oilfield flooding and fracturing. However, one major problem which limits the wide applications of HAWSPs is their weak resistance to high temperatures. Once the temperature increases over 100 °C, the viscosity of the fracturing fluid decreases rapidly, because high temperatures reduce fluid viscosity by oxidizing the polyacrylamide chains and weakening the association of hydrophobic groups. To improve the high temperature resistance of one HAWSP, a triple-protection strategy was developed. First, rigid N-vinyl-2-pyrrolidone moiety was introduced into the polymer chains. Second, an environmentally-friendly deoxidizer, carbohydrazide, was selected to prevent polymer oxidization by scavenging dissolved oxygen. Results showed that both the rigid groups and the deoxidizer improved the temperature resistance of the polymer and helped it maintain high viscosity under high temperature and shear rate. Using these two protection strategies, the resistant temperature of the polymer could reach 160 °C. However, the polymer network still got severely damaged at further elevated temperatures. Therefore, as the third protection strategy, the pre-added high temperature responsive crosslinking agent was applied to form new networks at elevated temperatures. The results have shown that the optimized polymer solution as a kind of fracturing fluid showed good temperature resistance up to 200 °C.

scholarly journals Crosslinking Dependence of Direct Current Breakdown Performance for XLPE-PS Composites at Different Temperatures

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 219
Author(s):  
Liang Cao ◽  
Lisheng Zhong ◽  
Yinge Li ◽  
Jinghui Gao ◽  
George Chen
Keyword(s):  
Elastic Modulus ◽  
Relaxation Process ◽  
Direct Current ◽  
Loss Tangent ◽  
Breakdown Strength ◽  
Crosslinking Agent ◽  
Temperature Stability ◽  
Peak Temperature ◽  
Increasing Trend ◽  
Different Temperatures

In this paper, crosslinked polyethylene-polystyrene (XLPE-PS) composites with different degrees of crosslinking were fabricated by using different crosslinking agent contents and their direct current (DC) breakdown performance at 30~90 °C was investigated. Results show that with the increase of the degree of crosslinking, the crystallinity of XLPE-PS composites decreases gradually, but their DC breakdown strength demonstrates an increasing trend at 30~90 °C and the enhancement also increases with the rise of temperature. And as the degree of crosslinking increases, the elastic modulus of XLPE-PS composites is reduced and the loss tangent peak temperature decreases but the peak shifts to a lower value, which reveals the suppression of the relaxation process for crystallites. It is believed that high DC breakdown strength with good temperature stability for XLPE-PS composites with a larger degree of crosslinking is attributable to the presence of PS and suppression in the formation of crystallites due to crosslinking.

scholarly journals Enhanced Electrical Properties of Polyethylene-Graft-Polystyrene/LDPE Composites

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 124 ◽  
Author(s):  
Shuwei Song ◽  
Hong Zhao ◽  
Zhanhai Yao ◽  
Zhiyu Yan ◽  
Jiaming Yang ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Direct Current ◽  
Density Functional ◽  
Breakdown Strength ◽  
Density Functional Theory Calculation ◽  
Low Density Polyethylene ◽  
Low Density ◽  
High Voltage Direct Current ◽  
Current Characteristics ◽  
Ldpe Composites

Nanocomposite dielectrics show a great potential application in high voltage direct current cables for their obvious improvements in electrical properties. In the present manuscript, nanocomposite composed of low-density polyethylene and nanoscale polystyrene particles is studied by using low-density polyethylene grafted with polystyrene molecule. Fourier-transform infrared spectra reveal successful grafting of the polystyrene molecule onto the low-density polyethylene chain and the scanning electron microscope image shows the homogeneously dispersed nanoscale polystyrene particles. The presence of the polystyrene nanoparticles obviously improves the dielectric properties, such as the direct current breakdown strength and space charge inhibition. The conductivity and thermally stimulated current characteristics imply the deep traps in the composite increase obviously. Density functional theory calculation reveals that the grafted polystyrene can accommodate both shallow and deep electron carriers, and the depth of the hole traps are as deep as 2.07 eV.

Irradiation Induced Crosslinking in “Green” Polylactic-Acid (PLA) Polymers for Enhanced Strength and Elevated Temperature Applications

2020 ◽  
Author(s):  
W. Jiang ◽  
A. Bakken ◽  
R. P. Taleyarkhan
Keyword(s):  
High Temperature ◽  
Polylactic Acid ◽  
Chemical Engineering ◽  
Elevated Temperatures ◽  
Crosslinking Agent ◽  
Industrial Applications ◽  
Significant Loss ◽  
Crystalline Form ◽  
Photon Irradiation ◽  
Gamma Irradiated

Abstract This paper presents interdisciplinary (nuclear-mechanical-materials-chemical) engineering technology and results pertaining to use of ionization radiation for tailoring “green”, renewable corn-soy based amorphous and crystalline form polymers for use as low-to-high temperature adhesives. Both amorphous and crystalline form polymer forms of such the Polylactic-Acid (PLA) polymer were studied with and without photon irradiation, alongside with and without cross-linking agent. In order to study and enhance the high-temperature application of PLA as a novel, multi-purpose adhesive, small concentrations of the crosslinking agent triallyl isocyanurate (TAIC) were included into molten amorphous and semi-crystalline PLA cast as glue sticks, followed with Co-60 gamma-irradiation. Bond strength variations were studied in tensile mode at room temperature using the resulting adhesive in between two steel dowels (head-to-head bonded) as well as via shear strength testing at elevated temperatures (50–120°C) under a set pre-load of 222 N. It was found that gamma irradiated samples with TAIC exhibited noticeably improved bonding strength, and importantly, such strength can potentially prevail towards 100°C. These are exciting results which offer potential for application for building construction and safety enhancements especially under fires and similar accidents. Samples without TAIC exhibited significant loss of strength past 90°C. The full paper will discuss details of apparatus, modeling and simulation of irradiation dose delivery, testing protocols results, and future enhancements via hybrid neutron-photon-electron irradiation for utility in variety of industrial applications.

Design Sensitivity Analysis Applied to High Temperature/High Voltage Direct Current Power Systems

2008 ◽  
Vol 44 (6) ◽  
pp. 1490-1493 ◽  
Author(s):  
J. Braunstein ◽  
Hyeong-Seok Kim ◽  
Hyang-Beom Lee ◽  
Tae-Kyung Chung ◽  
Un-Chul Moon
Keyword(s):  
Sensitivity Analysis ◽  
High Temperature ◽  
Power Systems ◽  
High Voltage ◽  
Direct Current ◽  
Design Sensitivity ◽  
Design Sensitivity Analysis ◽  
High Voltage Direct Current
Sign in / Sign up

Export Citation Format

Share Document