Study Of Resistance Calculation And Design Of Grounding Grid On Nonuniform Soil

With the rapid increase of the power system capability, ground fault current increase greatly. Most substations set up complicated region in the soil condition. How to design standard substation grids in non-uniform, using suitable decreasing resistance method to keep the safe and reliable operation of the power system stuffs and devices is crucial.Researches indicate that multi-layer soil structure model can represent actual soil structure and it is the base of design ground. First of all, the method for calculating stationary current field produced by a point current source in multiplayer media is, discussed. A complex image concept is introduced on the basis of the classical image method. An efficient method based on a complex image is derived for calculating Green's function of horizontal multilayer soil.Up till now, the principle measures adopted are as follows: expanding the area of grounding net. increasing grounding rod. soil renewal and use of preparation etc. it is very common to take measures on resistance reduction willfully, neglecting investigation of external conditions, geographic location and geology conditions. These measures often do not meet the requirements and even bring dangers to safe operation of electric power systems. Based on the study and analysis of each method, this thesis sums up its respective characteristics and scope of application. Results of this thesis provide the help for further study and takes notable effect in electric power engineering.Based on the research mentioned above. Adopting suitable and different ways of decreasing grounding resistance in different substations can meet the demands of different substation grounding resistance and can also meet the technical and economical demands, a substation of Lian Tang grounding system has been designed and completed successfully.