Simulation of impact of vertical grounding electrode on impulse grounding resistance of substation grounding network

In order to study the influence of vertical grounding electrode on impulse grounding resistance of substation ground network, the grounding model was built in COMSOL, and the impulse grounding resistances of substation grounding grid in different distribution, length and quantity of vertical grounding electrode were simulated and calculated. The results show that the closer the vertical ground to the lightning current injection point is, the smaller the impact grounding resistance is. The impulse grounding resistance, that has a minimum value, decreases first and then increases with the increase of the vertical grounding electrode length. When the additional vertical grounding electrodes are placed in accordance with the evacuation outside and internal density manner within a certain region ranging from the lightning current injection point, the impact grounding resistance has the best reduction effect.