Analysis on frequency and impulse characteristics of grounding grid

Studying the frequency and impulse characteristics of grounding grids is of great reference value for the optimal design of the substation. As the frequency increasing, the variation trend of the grounding resistance under different conditions is not same, which is affected by many factors. Therefore, this study focuses on the influence of grounding grid sizes, sparsity, soil resistivity, and grounding material on frequency and impulse characteristics. Based on these factors, the corresponding value of the grounding resistances at different frequencies and the impulse resistances are obtained by simulation. The trends of grounding resistances under different factors are analysed by using the dispersion mechanism. The simulation results show that the impulse grounding resistance will decrease with the increase of the grounding grid sizes and the conductor radius, or will decrease with the decrease of the spacing and the soil resistivity. With the increasing in frequency, the inductance effect of grounding resistance is strengthened, and the effect of soil resistivity and grounding grid parameters on grounding resistance become remarkable