基于核磁共振的XLPE电缆绝缘热老化试验研究

Heat Aging Test Research of XLPE Cable Insulation Based on NMR

摘要: 随着交联聚乙烯电缆在电力系统中的广泛应用，其老化行为成为电力系统长期安全运行的瓶颈，迫切需要我们研究其老化规律和机理。交联聚乙烯尽管具有较好的耐热性能和电性能。但在实际运行中长期处于高温下而发生化学变化，使得绝缘材料的物理性能和电气性能发生改变。本文按照IEC60287标准对XLPE绝缘材料进行热老化试验，利用核磁共振分析仪，选取共振峰积分面积和纵向弛豫时间为反应绝缘老化程度的特征量，对绝缘材料分子结构进行分析，得到更直观的老化程度结果；同时利用差示扫描量热分析技术对不同热老化程度的绝缘材料进行了热性能分析，提出了以玻璃转化温度、结晶度、结晶速率为指标的热性能分析技术。

Abstract: XLPE cables are widely used in the power system; the aging behavior of XLPE cable insulation be-comes the bottleneck of long-term safe operation of the power system. The urgent need is to study the law and mechanism of aging. Although the XLPE has good heat resistance and electrical prop-erties, in actual long-term operations, cables are always under high temperature, physical and electrical properties of the insulating material are slowly changed. This article did the heat aging test of XLPE insulation material according to IEC 60287 Standard. With the help of nuclear magnetic resonance analyzer, the resonance peak integration area and longitudinal relaxation time are selected as the feature quantities to characterize the degree of aging of the insulation. The molecular structure of the insulation material is analyzed to obtain a more intuitive aging results while taking advantage of differential scanning calorimetry analysis of the different thermal aging of insulation material thermal performance analysis, determined the glass transition temperature, crystallinity and crystallization rate as index of thermal performance analysis techniques.