在役高压电缆缓冲层缺陷检测

Detection of buffer layer defects of in-service high-voltage cables

缓冲层烧蚀故障是高压电缆故障的主要因素之一。由于现场环境复杂,而CT检测需要对物体实现一定角度的相对旋转,目前尚没有针对在役高压电缆CT检测的设备。采用射线源平移扫描局部CT成像方式,通过实验仿真和实验平台验证,设计了可用于现场应用的便携式检测系统,实现了在役高压电缆缓冲层缺陷在线CT检测。对于110 kV高压电缆缓冲层,可检出?1 mm的孔状缺陷,220 kV高压电缆可检出?2 mm的缺陷。收集2016张带有缺陷的CT图像后,结合802张同种结构电缆的圆周CT图像,采用迁移学习的方法,实现了缺陷自动检测,精确率为87.6%,召回率为93.5%,漏检率为6.5%,接近圆周CT的水平。

The ablation fault in the buffer layer is one of the main factors of high-voltage cable fault.Due to the complex on-site environment and the need to achieve a certain angle of relative rotation for CT detection of objects,there is no equipment for CT detection of high-voltage cables in service at present.A portable detection system for on-site application is designed by using the local CT imaging mode of X-ray source translation scanning and verified by experimental simulation and experimental platform,which realizes online CT detection of defects in high-voltage cable buffer layer in service.For the buffer layer of 110 kV high-voltage cable,the hole defect ofØ1 mm can be detected,and the defect ofØ2 mm can be detected for 220 kV high-voltage cable.After collecting 2016 CT images with defects,combined with 802 circumferential CT images of cables with the similar structure,the method of migration learning is used to achieve automatic defect detection,with an accuracy rate of 87.6%,a recall rate of 93.5%,and a missed detection rate of 6.5%,which are close to the level of circumferential CT.