scholarly journals Influence of Oxygen Diffusion on Thermal Ageing of Cross-Linked Polyethylene Cable Insulation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2056 ◽  
Author(s):  
Yuanyuan Zhang ◽  
Zongke Hou ◽  
Kangning Wu ◽  
Shihang Wang ◽  
Jianying Li ◽  
...  
Keyword(s):  
Oxygen Diffusion ◽  
Ageing Time ◽  
Oxidation Kinetic ◽  
Surface Region ◽  
Thermal Ageing ◽  
Cable Insulation ◽  
Carbonyl Index ◽  
Xlpe Cable ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Degradation Degree

Thermal ageing of cross-linked polyethylene (XLPE) cable insulation is an important issue threatening the safe operation of power cables. In this paper, thermal ageing of XLPE was carried out at 160 °C in air for 240 h. The influence of oxygen diffusion on thermal ageing of XLPE was investigated by Ultraviolet–visible spectrophotometer (UV–Vis), tensile testing, and Fourier transformed infrared spectroscopy (FTIR). It was observed that the degradation degree not only depended on ageing time but also on sample positions. The thermally aged samples were more oxidized in the surface region, presented a darker color, more carbon atoms appeared in the conjugate cluster, had smaller elongation at break and tensile strength, and a larger carbonyl index. As ageing time increased, the non-uniform oxidation of the XLPE samples became more prominent. The degree of non-uniform oxidation caused by oxygen diffusion was quantitatively studied by first order oxidation kinetic. The calculated results demonstrated that carbonyl index measured by FTIR was more sensitive to non-uniform oxidation with a shape parameter in the range of 1–2. The result shown in this paper is helpful for interpreting and predicting the non-uniform ageing behavior of high voltage XLPE cables.

Effect of Thermal Ageing on Physico-Chemical and Electrical Properties of EHVDC XLPE Cable Insulation

2021 ◽  
Vol 28 (3) ◽  
pp. 1012-1019
Author(s):  
Fan-Bo Meng ◽  
Xiangrong Chen ◽  
Chao Dai ◽  
Mengtian Zhang ◽  
Ashish Paramane ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Thermal Ageing ◽  
Cable Insulation ◽  
Xlpe Cable ◽  
Physico Chemical

Ageing Assessment of XLPE Cable Insulation by Residual Antioxidant Content

2020 ◽  
Vol 27 (6) ◽  
pp. 1795-1802
Author(s):  
Yuanyuan Zhang ◽  
Shengtao Li ◽  
Jian Gao ◽  
Shihang Wang ◽  
Kangning Wu ◽  
...  
Keyword(s):  
Cable Insulation ◽  
Xlpe Cable ◽  
Antioxidant Content

scholarly journals Mechanical Response of Al-1.09Mg2Si Alloy under Varying Mould and Thermal Ageing Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
O. I. Sekunowo ◽  
G. I. Lawal ◽  
S. O. Adeosun
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Ambient Temperature ◽  
Mechanical Response ◽  
Ageing Time ◽  
Thermal Ageing ◽  
Alloy Ingot ◽  
Solution Treated ◽  
Crucible Furnace

Samples of the 6063 (Al-1.09Mg2Si) alloy ingot were melted in a crucible furnace and cast in metal and sand moulds, respectively. Standard tensile, hardness, and microstructural test specimens were prepared from cast samples, solution treated at 520∘C, soaked for 6 hrs, and immediately quenched at ambient temperature in a trough containing water to assume a supersaturated structure. The quenched specimens were then thermally aged at 175∘C for 3–7 hrs. Results show that at different ageing time, varied fractions of precipitates and intermetallics evolved in the specimens’ matrices which affect the resulting mechanical properties. The metal mould specimens aged for four hours (MTA-4) exhibited superior ultimate tensile strength of 247.8 MPa; microhardness, 68.5 HV; elongation, 28.2% . It is concluded that the extent of improvement in mechanical properties depends on the fractions, coherence, and distribution of precipitates along with the type of intermetallics developed in the alloy during ageing process.

Effect of Electrical Aging on the Trap Parameter of HVAC XLPE Cable Insulation

2014 ◽  
Vol 672-674 ◽  
pp. 769-772
Author(s):  
Wei Wei Li ◽  
Qiang Shi ◽  
Chi Wu
Keyword(s):  
Crystallization Process ◽  
Melt Crystallization ◽  
Depolarization Current ◽  
Cable Insulation ◽  
Trap Charge ◽  
Xlpe Cable ◽  
Trap Parameter ◽  
Start Up ◽  
Electrical Aging ◽  
Two Peaks

The effect of electrical aging on the trap parameter of HVAC XLPE cable insulation was investigated in this work. Thermally Stimulated Current (TSC) was used to measure depolarization current. The variation of trap parameter was calculated by means of start-up method based on the Gaussian fitting curve of TSC data. It was found that, the activation energy and the amount of trap charge obtained from TSC peak at 243K and 348K were increased after electrical aging, which may be benefit to characterize the degree of aging. The amount of trap charge in the two peaks increases as the increase of oxide dipole after electrical aging. And charge trapped described by the TSC peak at melting temperature increased after aging. It is considered that the increase of charge in the TSC peak can be attributed to the release of trap charge in the melt crystallization process, which corresponds to the α relaxation process in XLPE insulation.

Development of a Portable XLPE Cable Insulation Detection Device

2014 ◽  
Vol 960-961 ◽  
pp. 881-884
Author(s):  
Xiao Guang Xi ◽  
Yu Yan Man ◽  
Chi Zhang ◽  
Ming Lei Wu ◽  
Yan Wei Dong ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Electromagnetic Wave ◽  
Electromagnetic Coupling ◽  
Partial Discharge ◽  
Power Cables ◽  
Cable Insulation ◽  
Xlpe Cable ◽  
Insulation Status

In this article, a portable XLPE cable insulation detection device is introduced. Such a device utilizes electromagnetic coupling, UHF electromagnetic wave and acoustic emission to detect partial discharge signals in power cables. By analyzing the partial discharge signals and cable temperatures, the insulation status of XLPE power cables is judged.

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