基于多种检测手段的高压电缆头绝缘放电诊断分析

Analysis on Insulation Discharge Diagnosis in High-voltage Cable Head Based on Multiple Detection Methods

高压电缆头制作由于结构封闭、部件复杂以及电场均匀度要求高,一直是一个难题。在利用红外精确测温、超声波和高频电流局放检测法的基础上,创新性地引入了X射线吸收衬度成像技术对电力电缆头进行无损检测。通过多种检测手段综合诊断及解体论证,对一起35 kV单芯高压电力电缆头绝缘放电案例进行了详细分析。分析结果表明:X射线吸收衬度成像技术能够有效辅助查找高压电缆头在制作或使用中老化产生的孔洞、裂缝等缺陷;多种检测方式相互验证,可以提高缺陷定性分析的准确率。文中率先将X射线吸收衬度成像技术应用于工程现场,实现通过图形查找高压电缆头故障缺陷,提高电力电缆故障诊断直观性和可靠性。

The manufacturing process of high-voltage cable head has always been a difficult problem due to the enclosed structure,complex components and high requirements of electric field uniformity.On the basis of infrared temperature measurement,ultrasonic and high-frequency current testing,X-ray absorption-contrast imaging technology is introduced to carry out the nondestructive testing for power cable head.Through the comprehensive diagnosis of various methods and disassembly,an insulation discharge case of a 35 kV single-core high-voltage cable head is analyzed in detail.The analysis results show that X-ray absorption-contrast imaging technology can effectively help to determine defects such as holes and cracks which are formed in manufacturing process or ageing process,and mutual verification of various methods can improve the accuracy of qualitative analysis for the defects.The proposed X-ray absorption-contrast imaging technology is firstly applied to engineering,which realizes searching defects by images,and improves the direct visualization and reliability of defects diagnosis for power cables.