基于IRC和电热加速老化试验的XLPE电缆绝缘性能研究

Research on XLPE Cable Insulation Performance Based on IRC and Electrothermal Accelerated Aging Test

为了研究66 kV XLPE电力电缆的绝缘性能,文中采用自主设计的加速老化试验平台,同时对三根样品电缆分别进行两个阶段的电老化、热老化以及电热联合老化.利用等温松弛电流法(IRC)分别对加速老化前后的样品电缆进行试验,分析老化因子的改变,研究电缆的绝缘性能变化.试验结果表明:经过两个阶段的加速老化试验,电老化样品老化因子分别增加3.70%和4.21%,而热老化样品老化因子分别增加4.82%和23.42%,说明电应力和热应力在影响绝缘老化性能中,热应力的“贡献”更大,且温度越高,热应力起到的作用越大;电热联合双应力作用下的样品老化因子分别增加13.04%和37.50%,电热联合作用下老化因子变化远大于单一应力作用的样品老化因子变化,说明电、热两种应力存在某种协同作用,联合作用会加快电缆绝缘劣化.

In order to study the insulation aging performance of 66kV XLPE power cable,this paper adopts the self-designed accelerated aging test platform,and simultaneously performs two stages of electrical aging,heat aging and electric aging combined aging on three sample cables.The sample cable after accelerated aging was tested by isothermal relaxation current method(IRC),and the change of aging factor was analyzed to study the insulation performance change of the cable.The test results show that the accelerated test of the two stages,the aging factor of the electric aging sample increased by 3.70%and 4.21%,respectively,while the aging factor of the heat aging sample increased by 4.82%and 23.42%,respectively,indicating that the electrical stress and thermal stress affect the insulation aging performance.The"contribution"of thermal stress is greater,and the higher the temperature,the greater the effect of thermal stress;the aging factor of the sample under the action of electrothermal combined with double stress increases by 13.04%and 37.5%,respectively,and the change of aging factor is much greater than the single stress The change of the aging factor of the sample indicates that there is a synergistic effect between the electric and thermal stresses,and the combined action will accelerate the deterioration of the cable insulation.