XLPE电缆绝缘加速热老化特性

Accelerated Thermal Ageing Characteristics of XLPE Cable Insulation

为探究长期运行环境下XLPE电缆绝缘的老化特性,在实验室条件下对电缆绝缘材料进行加速热老化实验,通过红外光谱、氧化诱导时间及频域介电响应测试,比较分析老化前后XLPE电缆绝缘的理化特性、电气特性变化规律。结果表明:红外光谱中的羰基峰值可用于定性分析XLPE绝缘材料的老化程度;XLPE绝缘高温下的降解随着老化时间的延长愈加严重,氧化诱导时间不断缩短;XPLE材料介质损耗因数频谱曲线的最小值tanδmin与材料老化程度相关且与测试温度无关,因此tanδmin可作为评估XLPE绝缘老化情况的特征量。

In order to study the thermal ageing characteristics of XLPE cable insulation in long-term operation environment,accelerated thermal ageing experiments were conducted on cable insulation materials in laboratory,and the physical,chemical,and electrical properties of XLPE cable insulation before and after ageing were analyzed by infrared spectrum test,oxidation induction time test,and frequency domain dielectric response test.The results show that the peak value of carbonyl group in infrared spectrum can be used to analyze the ageing degree of XLPE insulation qualitatively.With the increase of ageing time,the degradation of XLPE insulation at high temperature becomes more and more serious,and the oxidation induction time decreases continuously.The minimum value(tanδmin)of dielectric loss factor spectrum curve is related to the ageing degree of XLPE materials and unrelated to the test temperature,therefore the tanδmincan be used as a characteristic parameter to evaluate the ageing state of XLPE insulation.