Series Impedance and Losses of Magnetic Field Mitigation Plates for Underground Power Cables

Abstract

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 beside 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 multilayered 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.

Comparison of Screening Configurations for the Mitigation of Voltages and Currents Induced on Pipelines by HVAC Power Lines

“…A second mechanism exploits the magnetic properties of the material constituting the screen [6]. Indeed, a high-permeability screen constitutes a preferential path for the magnetic field produced by the power line, diverting it away from the pipeline.…”

“…The problem of protecting metallic pipelines from electromagnetic induction due to nearby power lines or substations has been extensively studied in the last decades [1][2][3][4][5][6]. These kinds of structures are widely employed for tasks such as water, oil, and gas transportation, and suffer from the effects of both DC and AC electromagnetic interference.…”

A Survey on Optimization Techniques Applied to Magnetic Field Mitigation in Power Systems

“…In this sense, there are no analytical expressions for evaluating the MF reduction provided by every possible shielding configuration, due to its complex geometric and material properties. There are only few cases where analytical expressions are derived [96,97,100,101], but these are usually based on simplified situations (infinite width shields, perfect magnetic or perfect electric materials, ferromagnetic cylindrical shields, etc.). So, numerical methods, such as FEM, are frequently preferred to address this problem [38,89,91,94,99,102,103].…”

Magnetic field evaluation around 400 KV underground power cable under harmonics effects

“…Various research works have been conducted on the MF produced by UPCs. However, some of them have used analytical approaches, while others are based on numerical and experimental techniques [13]- [15]. In [15].…”

“…However, some of them have used analytical approaches, while others are based on numerical and experimental techniques [13]- [15]. In [15]. The MF generated by a practical in-service underground pipe-type cable was calculated using a computational model finite element method (FEM) combined with the semianalytical boundary element method (BEM) is proposed in [16] to revaluate MF due to UPCs.…”