Optimum Design Of Grounding Grids Of Traction Substation On Arid Desert Regions

At present, ourcountry increases the construction of the High-speed Railway and generalspeed electric railway in the western region, and the main factor affecting the traction powersupply system is the ground of soil resistivity. Most areas in the northwest region of ourcountryare arid desert areas, so its high soil resistivity makes the design of grounding gridsmore difficult. In present paper, based on the major project of Ministry of railways, we startfrom the actual geological and soil structure toreduce the grounding resistance of substationreasonably and balance the surface potential effectively, so that to optimize the design ofsubstation grounding grid traction.Firstly, we expound the basic theoretical knowledge of the traction substation in detail,mainly consisting of the grounding resistance, the definition and calculation of the contactvoltage and step voltage. At the same time, we also make presentation of the components andtechnical indicators of the traction substation grounding grid.Secondly, accurate obtaining of the soil structure parameters is the basis for optimaldesign of grounding grids. Since the conventional ground network analysis method isapplicable to the equivalent uniform soil, while the soil is non-uniform, there are a lot ofdeficiencies in the method. In non-uniform soil, there are many analysis methods of theground network, but these calculation methods are related to derivatives, needing to be giventhe initial value of the parameter. In view of the defects existed in the above algorithms and inorder to establish a new computational model of the ground soil parameters,we start from thepoint of view of the hybrid algorithm, and apply pattern search method to the geneticalgorithm. The hybrid algorithm provides a new approach to the efficiently computing of theground soil parameters.Finally, because the soil resistivity is relatively high in the arid desert regions, it is veryimportant to make surface potential distribution as far as possible uniform. In present paper,optimization design of the grounding grid based on the particle swarm algorithm is proposed.The optimization function regards the best compression ratio as the optimization goals, whichestablishs with the objective of maximum distribution of the surface potential and minimalpotential difference. Comparing with calculated results using the methods from references, theparticle swarm algorithm can be the optimal form of grounding grid conductors rangingspacing layout.