Analysis of Rogowski Coil Shielding Effectiveness with External Vertical Magnetic Field Using FEM

Rogowski coil (RC) is shielded to reduce the effect of disturbed magnetic fields and magnetic coupling between RC and external magnetic fields. For proper design of magnetic shielding of the RC, shielding effectiveness must be calculated. The magnetostatic approach is used for analyzing shield effectiveness. This paper discusses the proposed magnetic circuit model considering hollow cylindrical structure having rectangular cross section of shielding. Magnetic shielding effectiveness in RC is examined under an external vertical magnetic field. Shielding effectiveness is calculated by considering the horizontal and vertical air gap inevitable for magnetic shielding. For validation purpose a wide range of design parameters are considered and designed using ANSYS Maxwell. Finite Element Method (FEM) is used in the simulation and its results are reported. Simulation results shows that, the magnetic shielding effectiveness relates to the relative permeability of the shielding and airgap in shield. From the results it is observed that, shield effectiveness for vertical air gaps is greater than horizontal air gaps for the range of shielding thicknesses and distances under study. The impact of relative permeability on magnetic shield effectiveness has been investigated. Results of simulations indicate that shield effectiveness is not affected for shield designed with higher relative permeability materials.