Abstract: Occupational exposure to anthropogenic magnetic field at 50/60 Hz has attracted much attention recently with considerable apprehensions due to probable health hazards. The measurements of this magnetic field in the transmission switchyard of hydropower stations were performed in a segmented manner via a calibrated Extech 480826 Triple-Axis meter placed on a constructed stand with three observation heights (1.0, 1.5, and 1.8) metres corresponding to regions of waist, chest, and head for a standard normal human. The one-way ANOVA test in SPSS software with a p-value set at 0.05 demonstrated statistically significant differences in extremely low frequency (ELF) magnetic field exposure. The Tukey Simultaneous 95% CI significant differences were noted when the difference of mean for locations (Shiroro and Kainji switchyards) based on each observation height does not cross the zero-reference interval region. Whereas Jebba with Shiroro or Kainji switchyards were not significantly different. Furthermore, the Tukey Simultaneous 95% CI of two-way ANOVA shows that the difference of mean for heights: (1.0 m versus 1.5 m), (1.0 m versus 1.8 m), and (1.5 m versus 1.8 m) were statistically significant to ELF magnetic field exposure based on locations. The induced electric field and current density simulations using COMSOL Multiphysics for the highest mean magnetic field of uniform exposure in the switchyards show that the evaluated values were less than the stipulated basic restriction of 0.8 V/m and 10 mA/m2 by ICNIRP standard. Therefore, this study has given an insight on the instant intensity, the extent of induction and the need for continuous monitoring as precautionary measures to safeguard occupational workforce from extreme and prolonged magnetic field exposure radiation in switchyards vicinity, and also some associated health hazards in the heights’ region are discussed.

Keywords: Health hazards, Hydropower transmission switchyards, Magnetic field exposure, Observation heights, Occupational exposure and Zero-reference interval region

Pages: 162-171