220 kV XLPE绝缘材料长期老化性能及寿命评价

Long-term Aging Performances and Life Evaluation of 220 kV XLPE Insulation Materials

高压电力电缆用交联聚乙烯(XLPE)绝缘材料的长期老化性能决定电缆的运行可靠性和工作寿命,为了评价220 kV国产XLPE绝缘材料长期工作可靠性,文中以进口220 kV XLPE电缆绝缘料作参照,系统地对比研究了国产220 kV试制电缆料在长期电、热老化特性上的差异。针对两款220 kV交流电缆绝缘料,首先开展了长期热氧老化实验,并采用力学性能测试、红外光谱和差示扫描量热法(DSC)对材料热氧老化行为进行了表征。之后针对片状试样开展了恒压电老化寿命测试,根据老化寿命理论模型,分别获得了两款220 kV XLPE绝缘材料的热氧老化和电老化寿命。热氧老化测试结果表明:国产试制料的氧化速率较慢,但结晶性能和机械性能较差,以机械性能降至初值的30%为绝缘失效标准,进口料与国产试制料的热氧老化寿命分别为32.85年和29.14年,国产试制料整体耐热氧老化性能稍逊于进口料。恒压长期电老化测试结果表明:进口商用料与国产试制料电老化寿命n指数分别为16.84和17.03,国产试制料的整体耐电老化性能相对稍优;国产220 kV电缆绝缘材料的长期老化性能已经达到与进口同级材料接近水平。

The long-term aging performance of cross-linked polyethylene(XLPE)insulation material for high-voltage power cables will determine the operating reliability and working life of cables.This work aims to evaluate the long-term working reliability of the domestic 220 kV XLPE insulation material.An imported 220 kV XLPE cable insulation materi-al was taken as a reference,and the electrical and thermal aging characteristics of domesticaly trial-produced 220 kV cable material were comparatively studied.For the two 220 kV AC cable insulation materials,the long-term ther-mal-oxidative aging tests were carried out,and the mechanical properties,infrared spectroscopy and differential scanning calorimetry(DSC)were used to characterize the thermal-oxidative aging behavior of the materials.Then the constant stress electrical aging tests were carried out using sheet samples.According to the aging life theoretical model,the ther-mal-oxidative aging and electrical aging lives of the two 220 kV XLPE insulating materials were evaluated.The thermal-oxidative aging test results show that the oxidation rate of domestic trial-produced material is slower,however,its crystallization and mechanical property are relatively inferior.If when the mechanical property is dropped to 30%of the initial value is set as the insulation failure criterion,the thermal-oxidative aging life of imported and domestic materials are 32.85 years and 29.14 years,respectively.The thermal-oxidative aging resistance of domestic trial-produced material is slightly inferior to that of imported material.The constant stress long-term electrical aging test results show that the n indexes of electrical aging life for imported material and domestic trial-produced material are 16.84 and 17.03,respec-tively.The electrical aging resistance of the domestic trial-produced material is relatively better.The long-term aging performances of domestic 220 kV cable insulation material have reached the level close to that of imported materials.