The paper presents results of synthesis, theoretical, and experimental studies of a robust system of active shielding of the magnetic field generated by overhead power lines with triangular conductor arrangements. The synthesis is based on the solution of a multi-criteria stochastic game, in which the vector payoff is calculated on the basis of the Maxwell equations solutions in a quasi-stationary approximation. The solution to the game is based on the algorithms of stochastic multiagent particle multiswarm optimization. The possibility of a significant mitigation of magnetic flux density and a reduction in the sensitivity of the system to the plant parameters uncertainty is shown. Three shielding coils are required to shield a magnetic field in a five-story building, and two shielding coils are sufficient to shield the same magnetic field in a single-story building. Practical recommendations are given on the reasonable choice of the spatial arrangements of the shielding coils of a robust system of active shielding of the magnetic field generated by an overhead power line with a triangular arrangement of conductors. The experimental research into the robust system of active shielding model of the magnetic field generated by overhead power lines with a triangular arrangement of conductors and two shielding coils is carried out. The comparison of experimental and calculated results of the magnetic flux density values in the shielding space shows that their spread does not exceed 30 %.