INVESTIGATION OF TRANSIENTS IN GROUNDING GRIDS

he grounding grid of a power system is very important for absorbing the harmful overvoltages and/or overcurrents during transients. The lightning surges frequently causes overvoltages and/or overcur- rents via the grounding grid. This may have dangerous effects on persons and/or equipment. Therefore, this paper reviews in detail the transient in grounding grids due to lightning surges. The grounding grid configura- tions and mathematical modeling are explained. Many configurations are used in the analysis such as one, four, sixteen meshes grounding configurations. Also, two injection points are analyzed: at the terminal and the middle of the grid. The analysis is carried out using ATP/EMTP. Many transient responses of voltages and currents at different points of the grounding grid for different configurations are calculated and compared. The peak voltage and current values are compared to be the basis of safety design of the grounding system.