Variable step size for calculation of electromagnetic fields of power transmission line using finite difference techniques

One of the most powerful techniques used for electromagnetic field computation in real structures is the finite difference method (FDM) for evaluation of electromagnetic fields established in systems of relatively small size such as power transformers and generators. This is due to the availability of powerful computers and the arising interest in electromagnetic interactions with strongly inhomogeneous structures having complicated geometries. Very little work based on FDM has been reported in the case of large systems with large size problem domain, which comprise long-distance power transmission lines. This paper focuses on developing FDM procedures for the numerical evaluation of electromagnetic fields established by currents in power transmission lines, particularly by those in single-phase-to-earth fault condition. Attention has been paid in this problem for creating a new and easy technique for solving the electromagnetic field at long distance from the transmission line using a technique based on a variable step size for the grid of FDM.