Calculation of potential distribution on grounding grids via finite difference method

ABSTRACTIn electrical plants, connecting the voltage free parts and the protection cords with their linkedsections via a conductor into the earth surface named as grounding. In order to obtaincontinuity of electrical systems and to save human life, the parts that applied voltage haveinsulated in electrical systems. At insulation against the earth, becoming a failure, as everytime a deterioration and penetration with various reasons, is inevitable. Grounding is one ofthe methods, which aims to keep the security of human life in such a possible fault condition.In this thesis, the grounding grids that widely used in electrical systems have analyzed withFinite Difference Method (FDM) because of the simplicity in calculations and high accuracyof the method and this method used theorically for analyzing the model grounding grids. Withthis goal, fundamental concepts regarding the grounding have given in section 2 and theinspections on grounding grids have stated in section 3. In section 4, obtaining the currentdistribution, self resistance and mutual resistance is stated with the use of numericalexpressions and in section 5, the potential distribution that correspond earth surface of boththe points inside the grid and the points up to reference earth has calculated. In addition tothese, solution of the potential distribution expressions on earth surface with FDM haveobtained and the results have shown in graphically. In the final section, attained results andsuggestions have mentioned.The theme that desired to highlight in this thesis is to express the calculation of the potentialdistribution on earth surface of a square grounding grid after a failure case with FDM, andillustrate the results graphically. By doing as, it has desired to be a reference for the groundinggrid model, which is planning to design.Key words: Grounding grid, self resistance, mutual resistance, current distribution, potentialdistribution, finite difference method.