Electric and Magnetic Fields of the High Voltage Auto transformer

摘要

The actuality of the problem of industrial electric and magnetic fields' action to the workers health and to the electronic equipment arises [1, 2] in recent years. There are European (EU) standards limiting the maximum electric and magnetic fields values, which are dangerous for the human health and can damage the electronic equipment. Recent studies show that the small electric and magnetic fields can have influence to the health of human who works at the existing powerful electrical equipment, too. By EU Directive 2004/40/EC [3] the magnetic field strength must not exceed 400 A/m and the magnetic flux density - 500 μT in the workplaces. Electric field strength should not exceed 10 kV/m. Implementation of this Directive is delayed in Lithuania. The Lithuanian main document governing the values of the electromagnetic field is the hygiene norm HN110: 2001 "The electromagnetic field of industrial frequency in the workplace." Magnetic field strength should not exceed 900 A/m, and the electrical field strength should not exceed 5 kV/m during the working day (8 hours). Now the trend is considered and discussed to reduce the maximum allowable amount of magnetic flux density value to the values equal to 0.2 or 0.3 mT. These values are equivalent to the magnetic field strength values that are proportionally reduced to 160 - 240 A/m.