直流与交流交联聚乙烯电缆料绝缘特性的差异及其机理分析

Difference in Insulation Characteristics and Mechanism Between AC and DC XLPE Cable's Material

为研究交、直流电缆料绝缘特性的差异及其相关机理,对比测试了不同温度下交、直流电缆料的空间电荷和介电性能等主要绝缘特性,并通过红外光谱分析了造成差异的机理。研究结果表明:相比较交流电缆料,直流电缆料的空间电荷性能更优异、直流场下的击穿分散性更小但短时击穿场强稍低、杂质离子电导更少;红外光谱分析发现交、直流电缆料中羰基含量不同,而羰基含量表征了主链的完整程度和极性基团的含量,因此认为交直、流电缆料主链的完整程度和极性基团的含量是影响其绝缘性能差异的主要原因。

In order to understand the difference between DC and AC cable materials in their insulation characteristics, we comparatively measured the space charge and electrical properties of DC and AC materials, and analyzed the reasons of causing the difference by some tests and FTIR. The results show that, compared with AC cable materials, DC cable ma- terial has better space charge distribution, smaller dispersion but slightly lower voltage of breakdown in DC fields, and less impurity ion conductance. FTIR results show that the amount of carboxide in DC cable materials is different from that of AC cable materials. Since the amount of carboxide is an index of the integrity of main chains and the concentration of polar groups, we find that the two are the main reason for the difference in electrical properties between DC and AC cable materials.