含针尖缺陷的XLPE电缆绝缘击穿行为的频率依赖特性研究

Frequency Dependence Characteristic Study of Breakdown Behavior of XLPE Cable Insulation with Needle Defect

研究了在20～300 Hz 频率范围内含针尖缺陷的电缆绝缘试样在变频电压和阻尼振荡波电压作用下的击穿特性,变频击穿采用连续升压和逐级升压两种方式.结果表明：连续升压下的变频击穿电压、逐级升压下的变频击穿电压和阻尼振荡波击穿电压分别在240 Hz、80 Hz 和170 Hz 附近出现最大值.电压形式和电场频率对含针尖缺陷电缆绝缘击穿特性的影响来源于空间电荷的注入及分布特性的差别,这种差别不仅导致击穿电压的不同,还导致击穿的微观路径产生显著变化.

The breakdown characteristic of XLPE cable insulation with needle defect in the range of 20-300 Hz was studied under the effect of variable-frequency voltage and damped oscillation wave voltagerespectively, in which the variable-frequency voltage used continuous rising mode and step by step risingmode. The results show that the breakdown voltage maximum under the continuous rising mode, step bystep rising mode and damped oscillation wave voltage appears at 240 Hz, 100 Hz and 200 Hzrespectively. The effects of voltage form and electric field frequency on the breakdown characteristic ofXLPE insulation are from the injection and distribution of space charge, which lead to the obviouschange of breakdown path.