Assessment of Magnetic Field Effects and Estimation of Associated Current Density of Electrical Injection Substations in Kano Metropolis

Abstract

The paper presents an assessment and estimation of human exposure to extremely-low-frequency (ELF) magnetic field generated in 33/11kV electrical injection substations equipment in Kano metropolis using the magnetic field model. The magnetic fields level were measured with the aid of hand-held “Trifield^TM 100XE Meter; frequency weighted” in different parts of the substations and the occupational exposure in a shift personnel was estimated by calculating the time weighted average exposure level (TWA) over the entire week and noting basically that the general public average exposure level to power frequency of 50 Hz is less than 2 mG (≡ 0.2 mT). The main objectives of this study are to assess the level of magnetic fields radiation in an injection substation and estimate induced current density level at the head region of the human body. Current density estimation at the head region was computed by using magnetic field model by assuming that the human body has a homogenous and isotropic conductivity and current path is circular. The result obtained was validated through comparison with the international guidelines and standards for safety occupational exposure set by the International Commission on Non-Ionising Radiation Protection (ICNIRP).

Keywords: Extremely Low Frequency (ELF), Electromagnetic Fields (EMF), Current Density, Magnetic field, Time Weighted Average (TWA), human body, physiology, radiation exposure, transmission lines.