Study On Impulse Characteristics Of Grounding Grid In Substation Based On CDEGS

The substation grounding grid is an important measure to maintain the stable operation of the power system and ensure the safety of the electrical equipment and the staff.When the substation is struck by lightning,due to the grounding grid of the inductive effect and lightning current characteristics of high-frequency,the potential of the grounding grid is rapidly increasing,which poses a threat to the personal safety of the staff,resulting in damage to the insulation of the electrical equipment and even a large power outage of the power system,which seriously affects the people's production and life and brings great losses to the economy.Therefore,it is very important to study the impulse characteristics of substation grounding grid.In this paper,the CDEGS software is used to build the grounding impulse characteristic calculation model,and the impulse characteristics of the grounding grid under different influence factors are analyzed.It is concluded that the soil resistivity,soil stratification,grounding wire conductor material and lightning current waveform have great influence on the impulse characteristics,and the area of grounding grid has a great influence on the impulse characteristics only within a certain range.The depth of the grounding grid has little effect on the impulse characteristics.Then,the impulse characteristics of the ground grid corrosion are studied.It is concluded that the corrosion of the conductor of grounding grid has little effect on the impulse characteristics of the grounding grid and the fracture of the conductor of grounding grid has a great influence on the impulse characteristics of the grounding grid.Finally,the grounding grid is optimized by increasing the grid density of the grounding grid and adding the vertical grounding pole near the lightning strike point,and the optimization effect is analyzed.It is concluded that increasing the density of the grid near the lightning strike point can not only reduce the maximum transient ground potential of the grounding grid,but also reduce the duration of the maximum transient ground potential rise.Adding the vertical grounding electrode at the lightning strike point can effectively reduce the maximum transient ground potential of the grounding grid,but increasing the length and the number of the vertical grounding electrode does not significantly increase the optimization effect.When the vertical grounding electrode and the grid density are used to optimize the grounding grid,the advantages of both can be achieved,and good results are obtained.