Phasing Effect on the Electric Fields Generated by High Voltage Overhead Power Lines

Abstract

To begin with, there are listed three reasons why the topic of control and reduction of electric field issued by High Voltage Overhead Power Lines (HVOhPL) must be given greater attention: the currents induced by the external electric field are vertical and pass through the most sensitive human cells and organs, the usual ambient levels are sometimes very close to the generally accepted reference values and there is also the advantage of checking the simulations with real field measurements that are not influenced by the constant change value of the phase currents. Then a synthesis of the electrical and geometrical characteristics of the high voltage transmission and distribution networks (used pylons and wires coordinates) is presented, an essential starting point for making simulations as close as possible to reality. The simulations have been performed with two accessible, easy-to-use programs, in which the phasing influence on E-field strength has been approached, while assuming the most common types of three-phase double circuits. The recommendations on optimum phasing differ depending on the relative distribution of the three phases: vertical line, horizontal line or isosceles triangle. Conclusions are also presented regarding the influence of soil conductivity on resulting E-field strength and on its descending slew-rate.