Optimization Design Of Grounding Grid For Hengshui District

Grouding grid plays a important role in the safe operation of substation. It is a great measure to ensure the reliable run of electrical system and the safety of operating personnel. And its most fuction is to make the fault current flow to earth, to limit the fault electrical potential, to control grounding potential gradient and to limit the step voltage and the touch voltage. Perfomance of the Grouding grid is paid much attention by the design department and run department.This article in view of Hengshui area soil electronic resistivity low characteristic, in the earth resistance, the surface electric potential rise the meet standards limiting value request under the premise, has studied when the guarantee step voltage and the contact tension do not exceed the allowed figure, uses the inhomogeneous grid design counterpoise the method. This article proposed the application interpolation and curve fitting's method obtains the step voltage and the contact tension computational method take the surface electric potential data as the foundation.And take a counterpoise model as the example, has analyzed the current injection spot, the mesh spacing, the network burying depth, network round factor docking network electricity parameter and so on angle, surface partial gravel as well as fence influences.Considering the lower soil resistivity, the grounding resistance did not require as a necessary condition for design of grouding grid and the total length of the steel is a optimization purpose when the step voltage and the touch voltage are required not to exceed the limit values.To compare with the calculated results of the electrical parameters, we choosed a actual substation whose grid are non-uniform in Hengshui district and measured the electrical parameters of the grouding grid. The results verify the correctness of the results and the feasibility of the grid using optimal unequal design.