Organ Dosimetry for a Worker Standing Under a 132 kV Power Line

Abstract

This paper investigates the induced electric fields and currents in a human body tissues and organs of a live-line worker standing right under the maximum sag-point (mid span) of a double circuit 132 kV transmission line located in Riyadh, Saudi Arabia. The main purpose of this study is to determine, if the electric fields and current densities induced inside the critical tissues of a human body such as brain and heart are within the exposure limits of the IEEE Standards C95.6 - 2002. The double circuit 132-kV, 60 Hz transmission line has a power rating of 293 MVA, a maximum recorded peak load current of 603 A. Charge simulation method and the Biot-Savart law have been adopted for computation of external electric and magnetic fields. Finite Difference Time Difference (FTDT) technique and anatomical human body model with more than 40 different tissues with 3 mm voxel sizes have been utilized to calculate organs internal induced electric field and circulating currents. Simulation indicates that, at 1.75 meter above the ground level and under the maximum sag-point of the 132 kV transmission line, the computed external electric field is 1689 V/m and the external magnetic field is 92 mG. These values are below the limits set by the IEEE Standards for external exposure for the live-line workers. The maximum induced electric fields in the brain and heart are 29.5 and 6.3 mV/m respectively. These values are below the IEEE Standard recommended limits of 53 mV/m for the brain and 943 mV/m for the heart. The maximum induced electric fields for all human tissues, excluding the skin, was at the bone marrow of the feet and is 1.86 V/m. This value is lower than the IEEE Standard limit of 2.1 V/m for extremities. Consequently, a worker standing under the maximum sagpoint of a 132 kV transmission line during the peak loading condition is safe from the short term effects of EMF exposure on human body tissues.