Comparison of the effectiveness of thriple-loop and double-loop systems of active shielding of a magnetic field in a multi-storey old buildings

Aim. The issues of comparing the effectiveness of reducing the level of the magnetic field in a five-storey old buildings generated by a single-circuit overhead power transmission lines with a triangular suspension of wires using a thriple-loop and double-loop systems of active screening, which respectively contain three or two compensating windings are considered. Methodology. Spatial location coordinates of the compensating windings and the currents in the shielding windings were determined during the design of systems of active screening based on solution of the maximin vector optimization problem, in whith the vector of objective function is calculated based on Biot-Savart's law. The solution of this problem is calculated based on algorithms of multi-swarm multi-agent optimization. Results. The results of theoretical and experimental comparing the effectiveness of reducing the level of the magnetic field in a five-storey old generated by a single-circuit overhead power transmission lines with a triangular suspension of wires using a thriple-loop and double-loop systems of active screening, which respectively contain three or two compensating windings are presented. Originality. For the first time, the comparison the effectiveness of reducing the level of the magnetic field in a five-storey old using a thriple-loop and double-loop systems of active screening are considered. Practical value. From the point of view of the practical implementation it is shown the possibility to reduce the level of magnetic field induction in a five-storey old buildings to the sanitary standards of Ukraine for real overhead power transmission lines currents with the help of a synthesized double-loop systems of active screening. A double-loop active screening system is simpler in comparison with a thriple-loop active screening system when implementing