Introduction  Massive usage of gas-insulated metal-enclosed switchgear (GIS) has caused serious electromagnetic interference, especially when the isolating switch in GIS is operated with small capacitive current, it does not have arc extinguishing ability, so it leads to multiple breakdowns of the dielectric between the contacts, and the voltage steep waves are rapidly refracted back and forth in the compact pipeline space to form a very fast transient overvoltage(VFTO).

  Method  In this paper, a transmission line model suitable for solving transient ground potential rise was used, combined with ATP-EMTP software to analyze and calculate VFTO and transient ground potential rise(TGPR).

  Result  The simulation is obtained and the TGPR at different measuring points in the model is 582~762 V. By comparing with the literature results, the error analysis shows that the maximum error is 3.77%.

  Conclusion  The result verifies the correctness of the simulation calculation.