A Study of Electromagnetic Field Model for Suspended Overhead Transmission Lines

Most of the electromagnetic field calculation methods for high-voltage transmission overhead lines assume that the three-phase conductors are horizontal long straight wires. Therefore, the derived electromagnetic field model will be different from that in the real environment. The geometry of the overhead line has a great influence on the electromagnetic field calculation, especially at the center point of the cable between the two towers, where the cable sags to the lowest point in space. In this study, mathematical modeling of 2D&3D electromagnetic fields in space is carried out. In the model, a suspended-line equation is used and both the cable sag amplitude and the cable length are considered. Finally, the mathematical model of the electromagnetic field of the suspended overhead line is completed with MATLAB. The change of electromagnetic field distribution can be observed by the sag change. This 2D&3D model can quickly and graphically understand the electromagnetic field distribution of overhead lines. In the future, it can be used as an evaluation tool for the electromagnetic field distribution of actual overhead lines. It can be used to assist electric power engineers or environmental assessment engineers in the electromagnetic field evaluation and improvement. In addition, it can be applied to the pre-construction estimation of new overhead lines.