DC Magnetic Field Reduction Inside Particular Part of Space

The attenuation of magnetic fields is important in many cases in order to protect living beings and electrical equipment from its harmful effect. This paper deals with the DC magnetic field reduction by shielding. A finite element method is applied to study the efficiency and reliability of various shield geometries, placed coaxially with a long current carrying wire, in order to decrease the magnetic field outside the shield. The impact of different combinations of permeability and thicknesses of applied ferromagnetic material is investigated. Calculating the shielding effectiveness, defined as the ratio of magnetic flux density magnitude without and with the shield, the most effective shields can be determined. The obtained results show that a partial shield can be good protection in many practical cases.