Influence of grounding resistance value of main grounding grid on substation safe operation

The problems were analyzed about the grounding resistance value of the substation main grounding grid, the phase-to-ground fault current value and the grounding potential rise of the main grounding grid. Combined with the design regulations, the calculation method of the grounding resistance value for the substation main grounding grid and the judgment to meet the actual operation condition were discussed. It is pointed out that the relational technique regulation of the grounding resistance value for the substation main grounding grid must be rightly comprehended. A series accidents caused by the bus failure of one substation in Tanjin further shows that electric operators should be clear about the conception of the grounding resistance value of the main grounding grid, and should attach more importance to the grounding resistance of the substation main grounding grid and strengthen the management. Thus existing problems and latent troubles of the substation main grounding grid would be eliminated, and further safe operation level of power grid can be improved.