Impact of using natural trees on the electric field reduction of Kuwait high voltage transmission systems

A very important part of the overall characteristics of high voltage transmission lines (HVTLs) is their electric field effects which can possibly affect human and animals by creating a potential electric shock hazard. These effects can be decreased by reducing the magnitudes of such fields. In this paper, a row of natural trees was used to shield a span of very HVTLs to reduce the electric field and, in turn, to reduce the edge of right-of-way (ROW) limits. The lines considered for the study were multiphase multiconductor transmission lines. The row of trees was approximated by a grounded cylinder parallel to the line. The effect of tree type was taken into consideration through the change of its height and equivalent radius. The proximity of trees row to the line and its influence on the limits of ROW were examined and clarified. The limit of ROW was determined according to the maximum allowable electric field at the edge of ROW. The analysis of two 3-phase, 275 kV, double circuit, bundle conductors TLs adjacent to each other and running in parallel using this method of shielding was also conducted. Graphs of electric field distribution at 1-m height above ground surface level for different design parameters of the cylinder are presented for a simple evaluation of the ROW limits at any maximum allowable electric field stress at the edge of ROW. The charge simulation method (CSM) was used to model the above mentioned systems with great accuracy.