ANALYSIS OF GROUNDING GRIDS AT LARGE SCALE SUBSTATIONS IN FREQUENCY DOMAIN

Based on the method of moment, a new method to analyze the grounding grids fed by harmonic current is presented. The method uses leakage currents as unknown variables that have small number and can be used to analyze the grids with frequency of the injected currents up to 1 MHz. In order to verify the method the grounding grid of a 500 kV substation is analyzed. The results are compared with those of world popular software CDEGS. Some experiments are also done on a practical small grid to validate both the method presented in this paper and the CDEGS software.