Analytical Shielding Metrics-Based Shielding Configuration Guideline for ELF Magnetic Field Mitigation

Abstract

This paper presents a simple guideline for configuration of the shielding materials that mitigates the extremely low-frequency (ELF) magnetic fields generated by power facilities located close to our daily life activities. Generally, materials with high permeability and conductivity are used to mitigate the magnetic field; however, in the current source region, before passing through the shielding material, the magnetic field may be increased by the configuration of the shielding material. To assess the effect of the shielding configuration in the current source and shielding regions, metrics are newly introduced, which were obtained based on the analytical solution for infinite width shields. In addition, the analytical solution of the shielding pipe wrapping a current source was deduced by solving the cylindrical Helmholtz equation. The shielding pipe is an important factor that can bring about changes in the metrics introduced in this study. The simple shielding guidelines suggested from these analyses help determine strategies for designing shields that can mitigate the magnetic field in both the current source and shielding regions.