Research of electric field characteristics of high-voltage overhead transmission lines adjacent to trees

Abstract

Safety hazards such as corona discharge， burning， and flashover occur atop trees adjacent to high-voltage transmission lines， resulting in power outages in severe cases. The simulated charge and matching points in the conductor and tree models are configured respectively by the variable step-size method and finite element mesh dissection to study the electric field distribution characteristics of overhead transmission lines adjacent to trees. The charge simulation method calculates the electric field distribution of horizontally aligned 500 kV overhead transmission lines in the presence of trees in the line corridor. The results show that the electric field intensity above the trees decreases with the increase in the number and density of trees. As the trees deviate from the central conductor to the side phase conductor， the electric field intensity above the crown decreases before it increases， reaching a maximum value of 20.5 kV/m at a deviation distance of 14 meters. The minimum midspan clearance between trees and 500 kV conductors is determined to be 1.2 meters according to the average electric field strength of the shortest path. The method provides a reference basis for line corridor vegetation management.

Keywords

• electric field distribution
• charge simulation method
• overhead transmission lines
• corona discharge