ELECTRIC FIELD COMPUTATION FOR 500 kV TRANSMISSION LINE USING FINITE ELEMENT METHOD

Abstract

In transmission line design, especially extra high voltage 500 kV transmission line, the computation of the electric field distribution below the line plays a very important role in order to assure the allowed electric field strength at the edge of ROW in inhabited area and toprotect people from the adverse effects of electric field. In ideal cases (the ground under the line is flat and in absence of physical objects disturbingthe field distribution), "analytical methods are the most satisfactory solution for problems ofelectric field calculations with exact results. However, in fact the ground is not flat and trees andstructures (houses, buildings ... ) are present under or in the immediate neighbourhood of the line. Using analytical methods in this case is impossible. So we have to use numerical solutions.With the advent of computing power, numerical methods are the most recent and rapidlyadvancing. They are very powerful electromagnetics analysis tools. Numerical methods cansolve very complex problems that the use of analytical approach is impossible.Among the various numerical methods, the finite element method (FEM) has a dominantposition because it is versatile, having a strong interchangeability and can be incorporated intostandard programs. •This paper presents the calculation method of the electric field distribution below 500kV single circuit transmission line, in an ideal case, by finite element method through the ANSYS software. The results of this method are the same as the analytical method. This is the base tosolve the problems of field distribution in case that the ground is not flat and trees and structuresare present in the line vicinity using finite element method.