Research on the Insulation On-line Monitoring of Single-core XPLE Cable Metal Sheath

The insulation performance of single-core XLPE cable metal sheath concerns the safe operation of the cable. In this paper, the grounding model of single-core XLPE cable metal sheath is analyzed, and sheath current method is proposed for on-line monitoring the insulation performance of single-core XLPE cable metal sheath. The testing results show that value of sheath current is closely related to insulation performance of metal sheath. Thus the criterions of "absolute value of sheath current" and "relative variable of sheath current" are proposed. Operation in the field shows that the on-line monitoring method can monitor the insulation performance of single-core XLPE cable metal sheath and enhance the reliability of cable.