Series-Impedance and Losses of Magnetic Field Mitigation Plates for Underground Power Cables
; Almeida, M. E.
IEEE Transactions on Electromagnetic Compatibility Vol. 60, Nº 6, pp. 1761 - 1768, December, 2018.
ISSN (print): 0018-9375
Journal Impact Factor: 1,083 (in 2008)
Digital Object Identifier: 10.1109/TEMC.2017.2764952
This paper deals with magnetic field mitigation techniques for underground power systems by using conductive or ferromagnetic shielding plates. Two new aspects are considered in this paper besides the shielding effectiveness analysis: the contribution to the series-impedance and power losses due to the conducting set formed by the shielding plate/earth return path. A finite thickness ferromagnetic or conductive shielding is assumed buried parallel to the soil/air plane surface in order to model the induction magnetic field mitigation of a power underground cable system in flat configuration. An analytical method, appropriate to deal with possible optimization procedures, is used based on the magnetic vector potential for multi-layered configurations where the shielding plate is treated as a different layer. Results for the magnetic field reduction factor at the soil surface are obtained for different shielding materials, different shielding thickness values as well as different frequency values. Results are validated by employing the Finite Element Analysis (FEA).