Modeling Trees Internal Tissue for Estimating Electrical Leakage Current

A part of power distribution system losses is related to the growth of trees beside power lines. Despite the fact that the first need for the reduction of tree losses is an accurate evaluation, a detailed study has not been done in this field thus far. Earlier works about trees interfering with power lines have not considered power loss and often studied it as a high impedance fault problem. In addition, these studies have been just focused on the leakage current measurement of some specific trees touching medium voltage distribution network, while it is low voltage network in urban and rural areas that has maximum reports of tree contact. Furthermore, the amount of leakage current greatly depends on the internal tissues of trees and environmental conditions. With regard to the differences in tree types and weather conditions around the world, losses will have different degrees; therefore, studies cannot be confined only to the results of some particular types of trees. Considering the shortcomings of these studies, this paper tries to determine a factor for environmental conditions. By applying this factor, the leakage current values for different weather conditions are estimated. Besides, this paper uses 3D finite element method for modeling tree losses by considering type of trees. For assessing the validity of the modeling results, the range of leakage currents is obtained from experiments in a real low voltage network. The results of this study remove doubt about the reliability of loss calculation and shows that loss estimation by modeling is an effective and reliable tool in this field.