Temperature gradient effect on the conductivity of an XLPE insulated polymeric power cable

Choo, W.; Chen, G.; Swingler, S.G.

doi:10.1109/icsd.2010.5568227

Cited by 8 publications

(4 citation statements)

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“…For P3a, for instance, we observe that σ DC is five‐fold higher at 90 °C compared to 70 °C (Figure S28, Supporting Information), an increase that is expected given the temperature‐dependence of charge conduction in high voltage insulation materials. [ 38,39 ]…”

Section: Resultsmentioning

confidence: 99%

“…For P3a, for instance, we observe that 𝜎 DC is five-fold higher at 90 °C compared to 70 °C (Figure S28, Supporting Information), an increase that is expected given the temperature-dependence of charge conduction in high voltage insulation materials. [38,39] Evidently, the selection of a judicious amount of IPCs in combination with tuning of the polymerization conditions results in materials that display a promising combination of thermomechanical and dielectric properties. The ionomers P2a and P4a, for example, offer a desirable combination of a low 𝜎 DC < 2•10 −14 S m −1 but high 𝜅 = 0.39 W m −1 K −1 , while the tensile storage modulus at 150 °C ranges from E′ ≈ 0.8 to 1.4 MPa, slightly less than reference XLPE (Table 2).…”

Section: Resultsmentioning

confidence: 99%

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Polyethylene Based Ionomers as High Voltage Insulation Materials

D'Auria

Pourrahimi

Favero

et al. 2023

Adv Funct Materials

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Polyethylene based ionomers are demonstrated to feature a thermo‐mechanical and dielectric property portfolio that is comparable to cross‐linked polyethylene (XLPE), which may enable the design of more sustainable high voltage direct‐current (HVDC) power cables, a crucial component of future electricity grids that seamlessly integrate renewable sources of energy. A new type of ionomer is obtained via high‐pressure/high‐temperature free radical copolymerization of ethylene in the presence of small amounts of ion‐pair comonomers comprising amine terminated methacrylates and methacrylic acid. The synthesized ionomers feature a crystallinity, melting temperature, rubber plateau modulus and thermal conductivity like XLPE but remain melt‐processable. Moreover, the preparation of the ionomers is free of byproducts, which readily yields a highly insulating material with a low dielectric loss tangent and a low direct‐current (DC) electrical conductivity of 1 to 6·10−14 S m−1 at 70 °C and an electric field of 30 kV mm−1. Evidently, the investigated ionomers represent a promising alternative to XLPE‐based high voltage insulation, which may permit to ease the production as well as end‐of‐use recycling of HVDC power cables by combining the advantages of thermoset and thermoplastic materials while avoiding the formation of byproducts.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Polyethylene Based Ionomers as High Voltage Insulation Materials

D'Auria

Pourrahimi

Favero

et al. 2023

Adv Funct Materials

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“…In the actual operation of the cable, due to the high temperature of the inner conductor, XLPE is actually working in a continuous gradient temperature [8]. The temperature gradient will change the conductivity, the electric field, and the charge transport characteristics; therefore, it will also change the electrical treeing characteristics [9][10][11]. Unfortunately, the effect of radical scavenger on electrical treeing characteristics under temperature gradient is still not clear.…”

Section: Introductionmentioning

confidence: 99%

Effect of radical scavenger on electrical tree in cross‐linked polyethylene with large harmonic superimposed DC voltage

Zhu

Hou

2022

High Voltage

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In this study, three kinds of radical scavenger Chimassorb 944, Tinuvin 622, and Tinuvin 770 are used to suppress the growth of electrical trees in cross‐linked polyethylene (XLPE) with transient superimposed voltage under the temperature gradient. The tree morphology, tree length, accumulated damage, and time to breakdown are used to investigate the effect of radical scavenger on the electrical treeing process. It is found that under the temperature gradient caused by the temperature rise on the high voltage side, only Tinuvin 622 can always suppress the electrical tree as the temperature gradient rises. Under the temperature gradient caused by the temperature rise on the ground side, the three radical scavengers can all suppress the electrical tree. The breakdown of electrical tree exhibits the strong DC polarity dependence. Meanwhile, energy levels of these three radical scavengers are calculated through quantum chemistry, and the results indicate that radical scavengers have greater electron affinity, smaller ionisation energy, and smaller energy gap than XLPE. According to the surface potential decay test results at 60°C, it is found that all three radical scavengers can introduce deep traps. The different performances of radical scavengers under different temperature gradients and voltages are determined by the trap distribution characteristics, the molecular structure and chemical reaction of the additives themselves. It is concluded that Tinuvin 622 has potential for use in high voltage direct current XLPE cable application.

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“…Key words: low-density polyethylene; nano-MMT; cooling methods; dielectric propeties 聚乙烯以其优异的电绝缘性能成为电气设备中应用极广泛的塑料产品 [1] 。为了提高设备运行的可靠性, 延长绝缘材料的使用寿命, 国内外相关学者尝试用不同方法改进聚合物绝缘性能, 其中采用无机纳米材料掺杂改善复合材料的电性能成为了人们关注的热点。已有的研究工作表明, 无机纳米材料的引入可以有效抑制聚乙烯绝缘中的电树枝和局部放电 [2][3][4] , 使复合材料电老化性能得到改善; 无机纳米材料还可改变聚合物体内陷阱能级的深度和密度, 从而影响复合材料的电导特性, 进而提高复合材料的介电强度和抑制空间电荷积聚的能力 [5][6][7][8] 。然而, 由于纳米复合材料结构及界面的复杂性, 影响其结构与性能的很多因素还有待进一步探讨。聚乙烯电缆在制备过程中必须经过冷却工艺, 冷却工艺的不同将对纳米复合材料的结晶行为产生一定影响 [9][10] , 其中结晶尺寸和结晶完整程度将影响复合材料的电导特性 [11] 。另外, 空间电荷的产生、运动和衰减不仅与外加电压有关 [12] , 与聚合物的结晶状态也有着密切关系, 因此研究制备试样时冷却方式对复合材料介电性能的影响具有一定的科学意义。本工作采用熔融插层法制备了经空气自然冷却、空气快速冷却、水冷却和油冷却的蒙脱土/低密度聚乙烯(MMT/LDPE)纳米复合材料, 对比研究了不同冷却方式对复合材料电导特性、击穿性能和空间电荷分布的影响。 (1) 式中, d 代表蒙脱土片层之间的平均距离; θ 为半衍射角; λ 为入射 X 射线的波长, λ 取值 0.154 nm; n 为衍射级数 [13] 。根据公式(1)的计算结果可知, 经表面修饰的纳米蒙脱土层间距从原来的 1.25 nm 增大到 2.39 nm 左右, 这表明 MMT 经表面修饰后片层间距 d 明显变大, 与 LDPE 基体的插层复合更为容易。从纳米复合材料 MMT/LDPE 的 XRD 图谱中可知, 在 3°~10°范围内基本看不到明显的峰值, 这说明纳米蒙脱土在低密度聚乙烯基体中已经剥离 [14] 。 2 FTIR patterns of MMT and MMT/LDPE specimens 之间形成了氢键, 氢键作用改变了基体材料的键力常数, 使其振动幅度有所变化, 吸收峰峰值降低 [16] 。…”

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Effects of Cooling Methods on Dielectric Properties of MMT/LDPE

Yu-Jia¹,

Zhang²,

Xue-Dong³

et al. 2015

Journal of Inorganic Materials

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The melting intercalation method was used to prepare montmorillonite/low density polyethylene (MMT/LDPE) nano-composites. Through natural air cooling, rapid air cooling, water cooling, and oil cooling methods, the effects of different preparation processes on the dielectric properties of the composites were studied. The MMT/LDPE composite materials were characterized by XRD, FTIR, AFM, PLM, DSC, and TSC test. All experimental results show that the surface modified nano-MMT particles have been exfoliated and uniformly disperse in polyethylene. Different cooling processes have influence on the crystallinity of the composites. The oil cooling sample has higher crystallization rate and smaller crystal size. The density and depth of trap in the composites with nano-MMT are increased, which effectively improves dielectric properties of the polymer. Space charge in the composites by oil cooling process is evidently inhibited under 20 kV/mm and 40 kV/mm field strength. The peak value of positive charge is decreased by 63.57% and 51.39% as compared with that of natural air cooling. The oil cooling sample shows the smallest conductivity, and the largest breakdown strength. In the frequency range of 1-10 5 Hz, the dielectric constant and dielectric loss angle tangent of other threetypes of rapid air cooling, water cooling and oil cooling samples de-

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Temperature gradient effect on the conductivity of an XLPE insulated polymeric power cable

Cited by 8 publications

References 4 publications

Polyethylene Based Ionomers as High Voltage Insulation Materials

Polyethylene Based Ionomers as High Voltage Insulation Materials

Effect of radical scavenger on electrical tree in cross‐linked polyethylene with large harmonic superimposed DC voltage

Effects of Cooling Methods on Dielectric Properties of MMT/LDPE

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