Effect of the variation of the charge distribution along multi-overhead transmission lines’ conductors on the calculation method of ground surface electric field

•New methodology to calculate the charge distributions along the OHTL conductors.•Parameters affecting these charges, such as conductors sag, tower.•Effect of these charges on the calculation of the vicinity electric field.

This paper presents a new methodology to calculate the ground surface electric field, produced by overhead transmission lines (OHTLs), taking into account the effect of the variation of the charge distributions along the conductors of multi-overhead transmission lines. In this paper, the effects of the conductors sag, the presence of the tower, replacing the sub-conductors of each phase with an equivalent conductor, the presence of the ground wires, and the presence of another overhead transmission line (OHTL) circuit on the electric charge distribution along the OHTL conductors and hence on the calculation of the ground surface electric fields are extensively studied. The suggested technique is verified by comparing its results with a measurement by the other. The suggested technique is based on both the Charge Simulation Method (CSM) and the Image Method (IM).