Blindagem ativa de campos magnéticos em baixa frequência

Abstract

Existing techniques for reducing magnetic fields at 60Hz, such as the use of metallic materials and changing the configuration of the system, are often inefficient and costly. The search for a solution that, while technically and economically feasible it is thus a major issue. Two main aspects are evaluated for the need to reduce low frequency magnetic fields: the minimization of the levels to which organisms are exposed and elimination of interference problems. Therefore, this paper presents the active shield as an alternative to reduce low frequency magnetic fields. It proposed a technique of active shielding for use in low voltage systems, based on the construction of an auxiliary system to generate magnetic fields that hold back the source of the original field. To test its efficiency, we constructed a bench trial and mediations of magnetic flux density were performed in different conditions of the field source. Comparisons with other techniques, such as the use of ferrous and nonferrous materials to shield the source, indicate that the active shield can be a good alternative to reduce 60 Hz magnetic fields in the application of the shield has been specially assessed for active systems high voltage, more specifically the transmission lines. Aiming to determine the parameters of active shielding that resulted in the greatest reduction. Magnetic field, we developed an optimization program. Moreover, the stones placed by active shielding in the original system were evaluated. Finally, it is worth emphasizing the importance of the transmission lines underground as significant sources of magnetic fields to the environment, which have been ignored by most studies on this topic. The strong growth in the number of transmission lines underground as significant sources of magnetic fields to the environment, which have been ignored by most studies on this topic. The strong growth in the number of transmission lines underground, along with the use of devices seeking to increase its transmission capacity, indicate that field-reduction techniques may be needed in the near future.