Cause Analysis and Countermeasure of Oil Leakage Caused by Cable Terminal Belt Expansion

Compared with the cross-linked cable, the oil-filled cable has the advantage of stable and reliable operation, and it also has certain advantages in facilitating to detect the insulation performance of the cable through non-destructive means. However, there may be leakage of insulating oil during the operation of the oil-filled cable, which has become an obstacle to the development and application of oil-filled cables. Recently, during the construction of a 110kV cable line, it was found that the A-phase cable terminal sealing strip and the insulating oil swelled, causing the top sealing strip to crack. This paper will make a detailed introduction about the leakage of cable insulation and then carry out the control experiment analysis of the defective cable insulation accessories after the initial determination of the causes of defects. It is verified through experiments that the incompatibility between the insulating self-adhesive tape and the polyisobutylene insulating oil is the terminal cause of the cable defect. In order to avoid the operation risk of the cable terminal with the same batch of self-adhesive tape, several construction and monitoring measures is proposed to help eliminate potential safety hazards in time and ensure the stable operation of the cable line.