Design of active loops for magnetic field mitigation in MV/LV substation surroundings

• New simpler active loops configurations, which only need three currents to be injected in the loops, are proposed to reduce the magnetic field generated by complex sources, such as MV/LV substations.
• The performance of these new configurations is analysed when reducing the average magnetic field in several regions around a MV/LV substation.
• An optimization procedure is implemented by means of a genetic algorithm to obtain the optimum location and the proper current to be injected in the loops.
• The performance of the active loops when applied to MV/LV substations is compared to that provided by conductive/ferromagnetic shields.
• The main differences, in terms of performance, and their proper application to MV/LV substations are highlighted.

This paper deals with the application and optimization of active loops for the mitigation of the magnetic field generated by complex sources, especially MV/LV substations. Various active-loop configurations are proposed, which are analyzed in several regions located close to a particular MV/LV substation, and the optimum geometry and location of the loops are obtained together with the optimum current (magnitude and phase) to be injected into the loops. All this is performed by means of a genetic algorithm in order to reduce the average magnetic field inside the target volume (inspection volume) to the minimum. The performance of the proposed active loops is compared with that obtained via other well-known mitigation technique, such as conductive/ferromagnetic passive shields. The main results are analyzed, and the differences, in terms of performance, between the two shielding techniques, and their proper application to MV/LV substations, are highlighted.