Research on Measures of Grounding Resistance Reduction for Substation Based on CDEGS

With the continuous development of China's power industry and the increasing capacity of the power system, there are more and more safety problems in the operation of the substation grounding grid. The grounding resistance is an essential factor affecting the safety of the grounding grid. The existing resistance reduction measures are designed by traditional methods, which are challenging to meet the needs of actual substation operation. In order to improve the reliability of the power supply and meet the needs for the safe operation of the substation, it is urgent to design a resistance reduction measure with excellent performance. Using the CDEGS simulation calculation software, we calculate the critical parameters of the grounding grid(such as grounding resistance, touch voltage and step voltage). As the grounding resistance is an essential factor affecting the touch voltage and step voltage, more superior resistance reduction measures are studied by using unequal spacing grounding grids and increasing the number of vertical grounding electrodes. The research result shows that: for the soil under horizontal stratification, the effect of the grounding grid with unequal spacing on reducing the grounding resistance is not apparent; increasing the number of vertical grounding electrodes can also achieve the effect of reducing resistance, but with the increase of the number of vertical grounding electrodes, the effect of reducing the grounding resistance is not significant. The use of unequal spacing grounding grids combined with an increase in the number of vertical grounding electrodes can stabilize the ground surface potential distribution and achieve the best resistance reduction effect.