With the continuous increase in the number and relevance of electric transmission lines and distribution networks, there is a higher exposure to the magnetic fields generated by them, leading to more cases of human electrosensitivity, which greatly necessitates the design and development of magnetic field mitigation procedures and, at the same time, the need to minimize both performance degradation and deterioration in the efficiency as well. During the last four decades, fruitful results have been reported about extremely low frequency magnetic field mitigation, giving a wide variety of solutions. This survey paper aims to give a comprehensive overview of cost-effective optimization techniques destined to magnetic field mitigation in power systems, with particular attention to the results reported in the last decade.

This paper analyzes the thermal effects derived from the use of different screen shapes when shielding the magnetic field generated by underground power cables. A parametric analysis is developed to show the influence of the geometrical and the electrical parameters of the shield on the maximum temperature achieved by the power cables in order to analyze the impact of this technique on the ampacity of the line. A 2-D finite element approach is employed in this study to verify the performance of different types of screens (horizontal plate, reverse-U, and H-layout) in terms of shielding efficiency, overheating of the power cables, and operational costs.

This paper focuses on the development of a low-cost system, based on Arduino, for the active shielding of magnetic fields generated by power systems at industrial frequency. The modeling of the source, the design and the optimization of the shielding loop, and, finally, the hardware (microcontroller, sensors, driven voltage source, etc.) and the control algorithm of a prototype system are described. A number of tests, developed through an experimental setup, are performed to validate the prototype. The main results are also discussed highlighting the capabilities of the proposed active shielding.

This paper analyzes different ways to electromagnetically simulate three-core armored cables in 3D by means of the finite element method. Full periodic models, as lengthy as 36 m, are developed to evaluate the accuracy when simulating only a small portion of the cable, as commonly employed in the literature. The adequate length and boundary conditions for having the same accuracy of full periodic models are also studied. To achieve this aim, five medium voltage and high voltage armored cables are analyzed, obtaining the minimum length of the cable that may be simulated for having accurate results in shorter time and with less computational burden. This also results in the proposal of a new method comprising the advantages of short geometries and the applicability of periodic boundary conditions. Its accuracy is compared with experimental measurements and the International Electrotechnical Commission (IEC) standard for 145 kV and 245 kV cables. The results show a very good agreement between simulations and measurements (errors below 4%), obtaining a reduction in the computation time of about 90%. This new method brings a more effective tool for saving time and computational resources in cable design and the development of new analytical expressions for improving the IEC standard.

In this paper, an in-depth analysis of the possibilities of mitigating the magnetic field generated from typical overhead power lines by the use of compensated passive loops is presented. Typical conductor arrangements (flat, alternate, and super-bundle) for distribution, subtransmission, and transmission levels are compared, regarding the passive loops' characteristics (arrangement, dimensions, parametric sensibility analysis) and the mitigation effectiveness in two different typical situations of interest area: at one side (unilateral) and both sides (bilateral) from the line. The passive loop configurations considered are single loop, 3-conductor 2 loops, and 4-conductor 2 loops. Practical conclusions about the more suitable solutions are included. To obtain the optimum location of passive loops, a genetic algorithm (the major aspects will be presented) has been developed.