The high voltage cable buffer layer defects are frequent

but the accurate diagnosis of defects cannot be realized only by the conventional detection means such as local discharge. The analysis of theoretical basis are carried out based on the cable buffer layer defect recognition mechanism and the factors influencing the imaging of cable to detect the defects of the buffer layer. Combined with laboratory verification

the detection technology of cable buffer layer defect are throughly investigated. As a result

the qualitative analysis and location of ablative defect in buffer layer is realized

and other foreign matter in cable structure could also be effectively recognized. The technology has been successfully applied to the live detection of 220 kV GuiHe I loop which effectively eliminating the hidden danger of the running line and achieving good results.