Based on the analysis of the power frequency grounding network

this paper focuses on the upgrading of the old grounding networks in some substations and the safety protection of the surrounding pipeline systems in the power grid

taking a 500 kV substation’s new grounding network renovation project and a 220 kV substation’s grounding network pipeline stray current interference protection project as examples. Based on the four-layer soil model calculated using ETAP Power Station and CDEGS

combined with the CDEGS grounding network simulation software

actual models of the new and old grounding networks and surrounding metal pipelines are built. The resistive coupling effects on the grounding networks and its surrounding structures under power frequency and high-frequency currents are compared and analyzed. This paper specifically examines the similarities and differences between the effects of lightning currents and power frequency short-circuit currents on substation grounding networks and surrounding pipeline systems

identifying weak points in the discharge and dispersion process of high-frequency lightning currents. The results show that high-frequency lightning currents cause a sharp increase in the ground potential at the current injection point

with a rapid stepwise decaying of current amplitude

resulting in minimal impact on the ground potential at the edge of the grounding network. When metal pipelines exist around the substation

the sudden rise in transient voltage can easily cause partial discharge in the pipeline insulation layer

leading to a sudden drop in the potential of the gas pipeline insulation layer and resulting in breakdown.