Objective To investigate the status of individual occupational exposure to power frequency electromagnetic field (EMF) in different substations.
Methods The EMF density in the workplaces of three different voltage substations and the workers' individual exposure levels of power frequency magnetic field were gauged.
Results The electric field densities recorded in the proximity of the 500 kV substation were higher than the other workplaces, of which the highest recorded electric field density was located under the disconnect switch bus bar (11.573 kV/m). The magnetic flux density values near high-current bus bar and reactors were the highest (767.79 μT). The value of EMF density reduced gradually with the voltage grade, and the lowest value was located in the office areas. The individual exposure levels of power frequency magnetic field were (1.50& #177;0.01)μT and (3.90& #177;1.32)μT in the 500 kV and the 220 kV substations respectively, and ranged from (0.02& #177;0.23)μT to (0.11& #177;0.10) μT in the office areas.
Conclusion Significant differences of electromagnetic field density distribution are found in various work places. Potential health risk could be expected in workers exposed to high electric field density and high magnetic field exposure levels of 500 kV or 220 kV substations.
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