Calculations in 3D of the magnetic fields generated by distribution networks

Utility workers carry out live working on overhead and underground distribution networks on a regular basis. These networks carry high currents and can generate relatively high magnetic fields. In order to assess the exposure of utility workers to these magnetic fields we have performed 2D and 3D calculations of the magnetic field surrounding complex overhead structures and inside cable vaults. For currents up to 400 A in the conductors of overhead structures, the volumes where the magnetic field exceeds 420 µT are small and do not extend very far from the conductors. This is also the case for the magnetic field generated by the cables inside an underground cable vault. The only exception to this finding is the rising pole structure.