scholarly journals Research on Mechanical, Physicochemical and Electrical Properties of XLPE-Insulated Cables under Electrical-Thermal Aging

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Dongxin He ◽  
Tao Zhang ◽  
Meng Ma ◽  
Wenjie Gong ◽  
Wei Wang ◽  
...  
Keyword(s):  
Power Systems ◽  
Aging Time ◽  
Degradation Mechanism ◽  
Dielectric Strength ◽  
Breakdown Field ◽  
Insulation Material ◽  
Oxidation Induction Time ◽  
Cable Insulation ◽  
Characteristic Index ◽  
Xlpe Cable

The stabilization of cross-linked polyethylene (XLPE) cables is crucial to the safe working of power systems. In order to investigate the aging characteristics of cable insulation in the process of operation, 10 kV XLPE cables were electrically-thermally aged at an AC voltage of 26.1 kV and three temperatures: 103°C, 114°C, and 135°C. Cable samples at five aging stages were cut into slices and tested to determine their mechanical, physicochemical properties and dielectric strength. The changes in these properties were analyzed in terms of aging time. The mechanical strength and oxidation induction time have the same changing trend of decrease, because the chemical bonds of the cable insulation material are fractured when the XLPE cable is aged. The AC space charge presented a trend of gradual accumulation with aging time. The breakdown field strength after AC voltage application decreases monotonically with aging time, which could be a characteristic index to evaluate the degradation degree of the cable insulation. This research contributes to the comprehension of degradation mechanism and discovery of aging assessment criteria, which is of great significance in assessments of insulation properties and fault detection on power cables.

scholarly journals Study on the Structure and Dielectric Properties of Zeolite/LDPE Nanocomposite under Thermal Aging

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2108
Author(s):  
Bai Han ◽  
Chuqi Yin ◽  
Jiaxin Chang ◽  
Yu Pang ◽  
Penghao Lv ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Aging Time ◽  
Thermal Aging ◽  
Aging Treatment ◽  
Dielectric Strength ◽  
Breakdown Field ◽  
Scanning Calorimetry ◽  
Aging Resistance ◽  
The Stability ◽  
Breakdown Field Strength

Nanodoping is an effective way to improve the dielectric properties and the aging resistance of polyethylene. Nano-zeolite has a nano-level porous structure and larger specific surface area than ordinary nano-inorganic oxide, which can be used to improve dielectric properties of low-density polyethylene (LDPE) nanocomposite. The zeolite/LDPE nanocomposites were prepared and subjected to thermal aging treatment to obtain samples with different aging time. Using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the differential scanning calorimetry (DSC) test to study the microscopic and structure characteristics, it was found that nano-zeolite doping can effectively reduce the thermal aging damage to the internal structure of the nanocomposite; carbonyl and hydroxyl decreased significantly during the thermal aging time, and the crystallinity effectively improved. Nano-zeolite doping significantly improved the morphology and strengthened the aging resistance of the nanocomposite. In the dielectric strength test, it was found that nanodoping can effectively improve the direct current (DC) and alternating current (AC) breakdown field strength and the stability after the thermal aging. The dielectric constant of nanocomposite can be reduced, and the dielectric loss had no obvious change during the aging process. Moreover, the zeolite/LDPE nanocomposite with the doping concentration of 1 wt % had the best performance, for the nano-zeolite was better dispersed.

scholarly journals Assessment of dielectric strength and partial discharges patterns in nanocomposites insulation of single-core power cables

2021 ◽  
Vol 11 (04) ◽  
pp. 2150022
Author(s):  
Ahmed Thabet ◽  
M. Fouad
Keyword(s):  
Dielectric Strength ◽  
Partial Discharges ◽  
Power Cable ◽  
Insulation Material ◽  
Power Cables ◽  
Cable Insulation ◽  
Electrical Stress ◽  
Different Shapes ◽  
Work Done ◽  
New Strategies

Nanoparticles succeeded to enhance the dielectric properties of industrial insulation but the presence of voids inside the power cable insulation still leads to formation high electrical stress inside power cable insulation material and collapse. In this paper, the dielectric strength of new design nanocomposites has been deduced as experimental work done to clarify the benefit of filling nanoparticles with different patterns inside dielectrics. Also, it has been studied the effect of electrical stress distribution in presence of air, water and copper impurities with different shapes (cylinder, sphere and ellipse) inside insulation of single core. In simulation model, it has been used finite element method (FEM) for estimating the electrostatic field distribution in power cable insulation. It has been applied new strategies of nanotechnology techniques for designing innovative polyvinyl chloride insulation materials by using nanocomposites and multi-nanocomposites. Finally, this research succeeded to remedy different partial discharges (PD) patterns according to using certain types and concentrations of nanoparticles.

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