Magnetic Field Shielding Of Underground Power Cables In Urban Areas: A Real-life Example
Free (open access)
L. Battistelli, A. Geri & G. M. Veca
In this paper the authors propose a parametric analysis of a typical 150 kV underground power cable line laid in urban areas. A coupled electro-magnetic and thermal formulation based on a finite element model (FEM) has been applied to estimate the magnetic pollution due to trefoil configuration or flat configurations at the thermal operating limit of the cables (cable ampacity). We also investigate the performances of open or closed shields, made of conductive and/or magnetic materials, in order to reduce the magnetic pollution due to existing or new installations, imposing as limitation the maximum admissible operative temperature of the cables. The influence of the effective operating conditions on the magnetic pollution generated by the power line has also been investigated. The proposed formulation takes into account the real geometrical dimensions and the effective physical characteristics of the involved materials. Keywords: finite element model, coupled electro-magnetic-thermal problem, low-frequency magnetic field, magnetic pollution, shielding. 1 Introduction During the last decade, the interest in power-frequency magnetic field calculation and shielding is growing due to the increasing concern of possible biological effects of electromagnetic fields on human health. These effects appear to cause or promote certain forms of leukaemia and brain tumours, as suggested by recent epidemiological studies focused on power-frequency magnetic fields. For this reason, in several countries, public concern has probably incited the Regulatory Standards to fix, for the maximum magnetic flux density value, more restrictive limits with respect to the human exposure.
finite element model, coupled electro-magnetic-thermal problem,low-frequency magnetic field, magnetic pollution, shielding