高压电缆射线检测典型案例分析

Ray detection analysis of typical cases of high voltage cable

高压电缆缓冲阻水层烧蚀缺陷是长期影响电网安全稳定运行的重大隐患。该文分别对不同电压等级的电缆金属部件和电缆绝缘部件开展缺陷射线检测研究,对电缆中间头和终端头的材料材质、压接插入深度、压接后接线端子与导体间隙等关键质控点进行检测,对绝缘外屏蔽层、缓冲阻水层、金属铝护层的气隙性缺陷以及电缆头的绝缘件的表面损伤等进行分析。针对某110kV电缆线路,该文利用射线技术带电有效检出该线路电缆本体多处缓冲阻水层烧蚀缺陷,缺陷检出点占总检测点的28%,实现110kV在役电缆线路的的实时动态在线检测,及时发现故障隐患,消除安全风险。同时,相关研究也指出电缆内部缺陷多发于电缆底部铝护套波谷接触部位的规律,并提出加强射线在电缆领域的检测评估应用和尽快更换该线路电缆的建议。

The ablative defect of the water barrier of the high-voltage cable is a major hidden danger that will affect the safe and stable operation of the power grid for a long time.The defects of metal parts and insulation parts were of different voltage levels thoroughly studied via radiographic testing in this paper.The key quality control points inspection concerning about material analysis,depth of compression insertion,gap between terminal and conductor after compression insertion of the middle of the cable head and terminal head were carried out.Except for the air gap disfigurement of insulation outer shield,buffer water barrier and metal aluminum sheath,the surface damage of the insulation of the cable head could also be analyzed.The detection of the ablative defects of several buffer water barrier layers in the cable body by means of X-ray technology for a 110 kV cable line were carried out,and the defect detection points accounted for 28%of the total detection points.The real-time dynamic on-line detection of 110 kV cable line in service is realized,the hidden trouble is found in time,and the safety risk is eliminated.At the same time,it is found that the defects tend to occur at the trough of the aluminum sheath at the bottom of the cable.Suggestions of strengthening the application of the X-ray in the detection and evaluation of the cable field and replacing the line cable as soon as possible are also put forward.