Ultrasonic characteristics of XLPE/SIR insulation under thermal aging condition for high-voltage cables and their correlation with insulation performance

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-09-23 DOI:10.1016/j.polymdegradstab.2025.111689

Renyou Li , Hantao Wei , Yuanwei Zhu , Shengtao Li , Yanhui Wei , Guochang Li

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引用次数: 0

Abstract

The aging state of insulating materials in power equipment directly affects the reliability and service life of its operation. Therefore, accurately identifying the degree of material aging is crucial for preventing equipment failures and ensuring the safety of the power grid. The electrical properties, physical and chemical properties, mechanical properties and ultrasonic characteristics of cable insulation Cross-linked polyethylene (XLPE) and silicone rubber (SIR) under thermal aging conditions were studied, and the correlation characteristics between the ultrasonic characteristics caused by aging and the electrical properties were explored. Furthermore, the intrinsic connection between the changes in the microstructure of materials and the degradation of their macroscopic properties was revealed through molecular dynamics simulation. Through molecular dynamics simulation, the intrinsic relationship between the microscopic structure changes of the material and the degradation of its macroscopic properties was revealed. The experimental results show that when XLPE is thermally aged at 135 °C (in air) and SIR at 175 °C (in air), the dielectric constant values of both materials gradually increase with the increase of aging time. After 1008 h, the dielectric constant of XLPE and SIR increased by 12.7 % and 31.7 % respectively. Under the same aging time, the volume resistivity of XLPE decreases from 1.8 × 10¹⁴ Ω·m to 2.1 × 10¹³ Ω·m, while the volume resistivity of SIR decreases from 1.71 × 10¹³ Ω·m to 6.79 × 10¹² Ω·m. The elongation at break and tensile strength of XLPE and SIR gradually decreased. The ultrasonic velocity of XLPE decreases from 2200 m/s to 1953.8 m/s, while that of SIR increases from 911.3 m/s to 1021.2 m/s. Simulation results show that the free volume and mean square displacement of XLPE increase after aging, while those of SIR decrease, which affect the change in sound velocity. The band gap width of the two materials decreases after aging, and the density of states changed, resulting in a decline in insulation performance. The ultrasonic sound velocity is significantly correlated with the aging degree of the material, and can be used as an effective indicator for evaluating the aging status of XLPE and SIR. This study establishes the correlation between ultrasonic characteristics and insulation performance during the aging process of materials through microstructure changes, providing a theoretical basis for on-site non-destructive testing of the thermal aging state of high-voltage cables.

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高压电缆热老化条件下XLPE/SIR绝缘的超声特性及其与绝缘性能的关系

电力设备中绝缘材料的老化状态直接影响其运行的可靠性和使用寿命。因此，准确识别材料老化程度对于防止设备故障、保障电网安全至关重要。研究了交联聚乙烯（XLPE）和硅橡胶（SIR）在热老化条件下的电性能、理化性能、力学性能和超声特性，探讨了老化引起的超声特性与电性能之间的相关特性。此外，通过分子动力学模拟揭示了材料微观结构的变化与其宏观性能的退化之间的内在联系。通过分子动力学模拟，揭示了材料微观结构变化与其宏观性能退化之间的内在关系。实验结果表明：当XLPE在135℃（空气中）和SIR在175℃（空气中）热时效时，两种材料的介电常数值随着时效时间的增加而逐渐增大。1008 h后，XLPE和SIR的介电常数分别提高了12.7%和31.7%。在相同老化时间下，XLPE的体积电阻率从1.8 × 1014 Ω·m下降到2.1 × 1013 Ω·m， SIR的体积电阻率从1.71 × 1013 Ω·m下降到6.79 × 1012 Ω·m。XLPE和SIR的断裂伸长率和抗拉强度逐渐降低。XLPE的超声速度从2200 m/s减小到1953.8 m/s， SIR的超声速度从911.3 m/s增大到1021.2 m/s。仿真结果表明，老化后XLPE的自由体积和均方位移增大，SIR的自由体积和均方位移减小，影响声速的变化。老化后两种材料的带隙宽度减小，状态密度发生变化，导致绝缘性能下降。超声声速与材料老化程度显著相关，可作为评价XLPE和SIR老化状态的有效指标。本研究通过微观结构变化建立材料老化过程中超声特性与绝缘性能的相关性，为高压电缆热老化状态的现场无损检测提供理论依据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.