国产与进口高压电缆交联聚乙烯绝缘耐热老化性能对比分析

Comparative analysis on heat ageing resistance of domestic and imported XLPE insulation for high voltage cables

对国产与进口两种220 kV电缆交联聚乙烯(XLPE)绝缘在90℃和135℃进行加速热老化试验,探究不同温度和不同时间的热老化条件对XLPE绝缘理化性能、力学性能和电气性能的影响规律,评估国产和进口XLPE绝缘的热老化寿命。结果表明:热老化引发的氧化反应导致XLPE试样中羰基峰的出现,老化温度越高,羰基峰越明显。老化后,XLPE试样的交联程度增加,破坏了结晶区的晶体结构,使结晶度下降,导致力学性能总体上出现了劣化。老化试样的分子链发生了断裂、降解,在电场作用下载流子运动加剧,致使交流电气强度下降。热老化寿命评估表明,国产XLPE绝缘料的热老化寿命大于进口XLPE绝缘料。综合对比各项性能表明,国产XLPE绝缘料与进口XLPE绝缘料水平相当。

The domestic and imported 220 kV cross-linked polyethylene(XLPE)cable insulation were carried out accelerated thermal ageing tests at 90℃and 135℃,and the effects of thermal ageing with different temperature and different time on the physical and chemical properties,mechanical properties,and electrical properties of XLPE insulation were investigated.The thermal ageing life of domestic and imported XLPE insulation were evaluated.The results show that the oxidation reaction induced by thermal ageing leads to the appearance of carbonyl peak in the XLPE sample,and the higher the ageing temperature,the more obvious the carbonyl peak.After ageing,the cross-linking degree of XLPE samples increases,which damages the crystal structure in the crystallization zone and decreases the crystallinity,resulting in the overall deterioration of mechanical properties.The molecular chain of the aged sample is broken and degraded,and the movement of carrier is intensified under the action of electric field,resulting in the decline of AC electric strength.The thermal ageing life evaluation shows that the thermal ageing life of domestic XLPE insulation material is greater than that of imported XLPE insualtion material.The comprehensive comparison of various properties shows that the level of domestic XLPE insulation material is equivalent to that of imported XLPE insulation material.