A circuital approach to estimate the magnetic field reduction of nonferrous metal shields

The reduction of magnetic fields is a topic of concern to the electric utility industry and the electromagnetic compatibility community. One technique to reduce the magnetic fields is to use metal plates and enclosures for shielding, in addition, knowledge or the loading effect of a conducting structure in close proximity to power cables is needed for estimating power loss. Until now there has not been a simple and efficient method to calculate the low frequency magnetic shielding of, nor power loss caused by, two-dimensional shields. This paper presents a method for the rapid numerical estimation of the magnetic shielding efficiency and power loss of nonferrous metal structures. The method was validated analytically and experimentally.