Magnetic field in an apartment located above 10/0.4 kV substation: Levels and mitigation techniques

The paper presents a real case of non-ionising radiation testing in an apartment located directly above a 10/0.4 kV substation in Serbia. In order to check the compliance with national regulations on protection of population from non-ionising radiation, it was necessary to perform measurements of magnetic flux density in the apartment. After the first measurements were performed, the distribution company implemented a mitigation technique by placing a passive conductive shield inside the substation in order to decrease magnetic field levels in the apartment. Measurements performed after the mitigation technique had been implemented have shown that the applied shield had an impact on magnetic field reduction to a certain extent. However, since the obtained shielding factor was not very high, the authors analysed another possible shielding solution which would provide higher shielding factor and consequently lower magnetic field levels in the apartment. Both shielding solutions and the results they provide are presented and analysed.