Glass Fiber Reinforced Plastic (GFRP) is usually employed as the insulator material of superconducting cable terminal, owing to its excellent mechanical properties and insulation strength at cryogenic temperature. However, in the presence of a void defect, both the insulation life span and mechanical strength of GFRP decrease significantly at superconducting temperature conditions. In this paper, efforts have been made to investigate the degradation process of GFRP at cryogenic temperature and give insight into its degradation mechanism. By comparing PD activities at 278.7 K, 223 K and 153 K in initial phase of aging, it is found that PDs are inclined to be inhibited at lower temperature. Experiments indicate that the deposited charge accumulation and mechanical properties degradation, instead of chemical aging and PD energy, play a crucial part in dielectric degradation. At cryogenic temperatures, the local heat accumulation brought by PDs increases the material internal mechanical stress, and the accumulation of deposited charges causes instantaneous energy release. On the basis of the decrease of the mechanical properties of the material, the crack expands rapidly, which leads to the dielectric failure of the material. In conclusion, the degradation of GFRP at cryogenic temperature is the result of the combined effects of deposited charge accumulation and mechanical properties decline.

中文翻译：

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尝试了解具有空洞缺陷的GFRP绝缘子在低温下的降解过程

玻璃纤维增​​强塑料（GFRP）由于其优异的机械性能和低温绝缘强度，通常被用作超导电缆终端的绝缘材料。然而，在存在空隙缺陷的情况下，GFRP 的绝缘寿命和机械强度在超导温度条件下均显着降低。在本文中，已努力研究 GFRP 在低温下的降解过程并深入了解其降解机制。通过比较老化初期278.7 K、223 K和153 K下的PD活性，发现PDs在较低温度下倾向于被抑制。实验表明，沉积的电荷积累和机械性能退化，而不是化学老化和 PD 能量，在介电退化中起关键作用。在低温下，PDs带来的局部热量积累增加了材料内部机械应力，沉积电荷的积累导致瞬时能量释放。在材料力学性能下降的基础上，裂纹迅速扩大，导致材料介电失效。总之，GFRP在低温下的降解是沉积电荷积累和力学性能下降共同作用的结果。在材料力学性能下降的基础上，裂纹迅速扩大，导致材料介电失效。总之，GFRP在低温下的降解是沉积电荷积累和力学性能下降共同作用的结果。在材料力学性能下降的基础上，裂纹迅速扩大，导致材料介电失效。总之，GFRP在低温下的降解是沉积电荷积累和力学性能下降共同作用的结果。