Abstract: In recent years, there have been frequent breakdowns and burnout faults in the sheath protector of high-voltage cables. To optimize the design of the cable grounding system and provide a reference for protector selection, the electromagnetic transient simulation software PSCAD/EMTDC is used to establish a power cable line model. Considering various grounding methods for long cable lines in practical engineering projects, the study investigates the variation patterns of sheath overvoltage along line during single-phase grounding faults, with respect to different cable lengths, grounding resistances, and the installation of return cables. The research results show that after a single-phase grounding fault at the end of the cable, the overvoltage along line level of the 220 kV cross-interconnection cable sheath ranges from 2～8 kV. For the cross-interconnection hybrid single-end/mid-point grounding method, there is a characteristic of increased ground potential at the sheath connections, which can reach as high as 16 kV in severe cases. The installation of a return cable has a significant effect in suppressing the overvoltage of the cable sheath in the single-end grounding method, which is beneficial for the selection of protectors.

    Key words: high-voltage cable; metal sheath; cross-interconnection; overvoltage; return cable; protector; grounding resistance