一起电缆接头缺陷的多维度分析与解体验证

Multidimensional Analysis and Disassembly Verification of Cable Joint Defects

振荡波局部放电检测对电缆中间接头缺陷的检测十分有效。首先,通过一起电缆中间接头缺陷案例,对比了振荡波检测时长电缆首端、中间、末端位置的局放脉冲对的差异,得出了局放点向两个方向传播的脉冲波形幅值不相等的规律。其次,对其中一个中间接头进行了解体分析,发现存在应力锥搭接过盈等严重的施工质量问题,在解体的基础上分析了放电的原因。最后,对比分析振荡波局放检测与工频局放检测的试验结果后发现,此类缺陷,振荡波电压激发的放电次数明显少于工频电压,且在振荡波电压激发下,放电次数会随着振荡波电压的升高而增加,在工频电压激发下,放电量会随着电压的增加而增加。

PD detection in oscillation voltage is very effective for defects in cable joints. In the first, PD pulses from the head /middle/end of long cable were compared in the presence of an defect case, it was found that the amplitudes of PD pulses from PD position were different. In the second, one of cable joints with defect was dissected and it was found that there were construction quality problems such as stress cone dislocation, on the basis, the reason for PD was analyzed. In the end, after comparison of test results in the oscillation and 50 Hz voltage, it was found that, the number of PD in oscillation voltage was less than the number of PD in 50 Hz voltage and with the voltage increased, the number of PD in oscillation voltage increased apparently while the pC value of PD in 50 Hz voltage increased apparently.