ORGANISATIONAL AND TECHNICAL MEANS OF NORMALISING ULTRA-LOW FREQUENCY ELECTROMAGNETIC FIELD LEVELS

Abstract

The main approaches to normalizing the electromagnetic environment in general-purpose buildings and structures have been investigated. It has been determined that the most common resonant systems for simultaneous compensation of reactive power and suppression of higher harmonics and interharmonics of industrial frequency electric current (voltage) are ineffective in the presence of a complex spectrum of harmonics and interharmonics. It has been experimentally determined that in modern buildings and structures with a large number of electrical consumers with non-linear volt-ampere characteristics, the spectrum of interharmonics, including subharmonics, is complex and unpredictable. It has been shown that modern universal systems for suppressing harmonics and interharmonics are expensive and are suitable for use in enterprises with high electricity consumption for energy saving. A scheme for suppressing harmonics and interharmonics of industrial frequency electric current with feedback using a transformer is proposed. This approach is appropriate for unpredictable changes in the harmonic composition of the voltage in the power supply system. It is shown that interharmonics generation is also possible in buildings with a relatively small contribution of non-linear electrical consumers to the total load. Interharmonics can be generated as a result of modulation phenomena in voltage drop processes when powerful electrical consumers are switched on. The procedure for developing organizational and technical measures for electromagnetic safety based on electromagnetic monitoring is provided. It is emphasized that at the first stage of such work, it is necessary to ensure uniformity of the load on individual phases of the power grid, conduct a complete overhaul of reactive power compensation systems and eliminate leakage currents.