Research On Simulation Calculation And Performance Analysis Of Grounding Network Of Traction Substation

With the rapid development of China's electrified railway technology,the traction load capacity has been continuously improved,the traction short-circuit capacity has continued to expand,and the technical requirements for the grounding grid have become higher and higher.Traction substation grounding grid is of great significance for the safe and reliable operation of the entire traction power supply system.At present,due to the increasing integration of the high-voltage switchgear,the area of the grounding network of the traction substation is continuously reduced,which brings challenges to the system design.The grounding impedance value is one of the main indicators to directly measure the good or bad grounding system.It is a factor that reflects the macroscopic state of the grounding grid.At the same time,the surface potential,contact voltage and step voltage that reflect the local characteristics of the grounding grid are also concerned by the industry.And become a hot spot in industry research.In this dissertation,the Green's function theory of constant current source in semi-infinite space potential distribution is used.The algorithm of the moment method and the classical image method are used to establish the spatial distribution model of the grounding grid conductor,and the grounding impedance value and field of the grounding network of the traction substation are calculated.The distribution of surface potential and the potential of any position within it provide theoretical guarantee for ground safety analysis.In this dissertation,the grounding network analysis application software is developed by using M language and GUI module of MATLAB.The software achieves the purpose of rapid analysis of grounding resistance and surface potential distribution,and draws a three-dimensional graph of surface potential distribution in the field of traction substation,visually showing its potential distribution.The software can provide a theoretical reference for optimizing the grounding conductor distribution and reducing the grounding grid resistance scheme.In this dissertation,the theoretical model of the grounding network of the actual traction substation is built,and the grounding resistance and surface potential are analyzed.Compared with the international grounding analysis software CDEGS,the relative difference of all potentials is within 5%,and the relative difference between the calculated resistance and the national standard is 4%.Within the above,the correctness of the software algorithm is verified.Moreover,the software is more in line with domestic design experience,and the parameters of the grounding grid are more stringent.The grounding resistance of the traction substation was tested in the field.The numerical results are basically similar to the simulation results,which verifies the practicability of the software.Finally,through the analysis of the different grounding resistance values of the grounding grid of the substation,from the perspective of analyzing the trend of rail current,ground return and rail potential,the influence of the grounding grid resistance of the substation on the grounding system is analyzed.Measures to provide theoretical support for the optimization design of large complex grounding grids in the future.