SCREEN SELECTION FOR THE POWER FREQUENCY MAGNETIC FIELD SHIELDING OF UNDERGROUND POWER CABLES

In recent years, there is a social concern about the adverse effects derived from the magnetic field generated by power frequency electrical installations near public areas. A good example are underground power cables. One of the most used techniques to mitigate the magnetic field generated by underground power cables is screen shielding. However, it is difficult to choose the type of screen to use in a particular situation and it dimensions. The main objective of this paper is to show the recommended steps to select and design a suitable screen for a particular case, taking into account economical and technical aspects to meet the mitigation requirements in the final placement. The case of a 132 kV underground power line is taken as an example to show how these steps can be applied. The proposed steps are derived from an in-depth review of the most used screen shapes, and from numerous simulations carried out by means of numerical methods, such as the finite elements method, to solve the coupled electromagnetic-thermal problem.