Power-frequency Electric Field Caculation Of High Voltoge Transmissian Lines Under Condition Of Complex Scene

Our country has a vast territory,resources and loads are distributed in the opposite direction.The HV and UHV long-distance transmission network covering the whole country has been initially established and is under continuous development.HV and UHV transmission lines have high operating voltages,and the harm caused by electromagnetic fields to surrounding people,animals,and objects cannot be ignored.The quantitative calculation of the relationship between the electric field distribution in the transmission line corridor and environmental factors such as terrain,geology,vegetation,and structures has guiding significance for optimizing the design of transmission lines.This article first studies the method of calculating the electric field distribution of the retransmission line that takes the above factors into account,and then analyzes their influence.The main contents include:1)By comparing the calculation speed and resource occupancy in the calculation of the three-dimensional electric field in a single medium,the finite difference method is selected as the electric field calculation method in this paper.Aiming at the problem that the original difference calculation formula cannot be applied in the multi-media threedimensional space,the seven-point difference calculation formula at the interface of the medium is derived.2)Using DEM to establish a terrain model,treating vegetation as a homogeneous medium,and tree crowns and trunks as two different media,and analyzing the influence of terrain,vegetation,trees and their combinations on the electric field distribution around the transmission line,Proposed the use of environment to reduce the intensity of the electric field.3)Aiming at the situation that the electric field around the transmission line is stronger than the normal operation under certain fault conditions,the change of the electric field intensity around the transmission line under the fault with the type of the fault is calculated and analyzed.Aiming at the change of electric field with the parameters of the transmission line,suggestions are given to reduce the electric field intensity under fault conditions.