Calculation Approach for Risk Assessment of the Magnetic Fields under Overhead Power Lines

The paper is dedicated to a research about the influence of the parameters of the structure of the poles, utilized in overhead electrical lines 220 kV, over the assessment of the risk, connected with the magnetic field exposure. A new special methodology for calculation of the module of the magnetic flux density around the overhead electrical lines is presented. On its base an automated computer program in the environment of MATLAB, created by the authors, was developed. It allows simulation of the electromagnetic processes under overhead electrical power lines at a given height from the earth, in transverse direction from the poles of the power lines 220kV. Here, it is assumed that the phase lines are rectilinear and infinite. They are considered near to the horizontal surface of the ground, which is scrutinized as conductive medium. The magnetic field under the overhead electrical power lines is examined as a sum of the magnetic fields of the phase lines and the mirror images, which they have in the earth. In this way the vector of the magnetic flux density can be expressed as a vector sum caused by the phase lines and their images in the ground. The final results are presented for one of the most used constructions of electrical power line poles with triangular arrangement of the phase conductors.