Study On Modeling And Non-Uniform Resistivity Soil Earthening Of Substation Radio Frequency Invasion Overvoltage

As the demand for electricity in today’s society is growing,so the power system in the power grid voltage level is getting higher and higher,while the substation voltage level is also getting higher and higher.For these high-voltage substation,if the lightning waves into the substation and lead to over-voltage,will greatly affect the power system power supply reliability.It can be seen from the substation lightning wave intrusion over-voltage modeling is of great significance.In this paper,open-type substation with voltage rating of 500kV is taken as the research object,and EMTP simulation program is used for simulation.According to the characteristics of the lightning current,the simulation model of the lightning current is established.Then,the simulation model of the electrical equipment in the transmission line,the insulator string,the arrester,the tower and the substation is established.Then,the FORTRAN self-According to the results of simulation calculation,some conclusions are summarized,which can be used as reference for the lightning protection configuration of the actual substation.In addition,a detailed study of the over-voltage protection grounding of the substation is carried out.First,a new type of elliptical and cylindrical grounding device is introduced.Then,the grounding resistance of the grounding device in single layer,double layer and uniform resistivity soil is put forward And the method of calculating the grounding resistance of the grounding device based on the method of moments is put forward,and the calculation method of self-resistance and mutual impedance is given.On the basis of previous research,the boundary element method is used to study the grounding of non-uniform resistivity soil,and then the Green function model of horizontal stratified soil,vertical stratified soil and composite layered soil is established and The grounding resistance of the grounding device under different non-uniform soil conditions is obtained.Finally,the results are compared with the calculated results of the software,which proves the validity and accuracy of the method.