Calculation Of Diffusion Resistance For Contact Terminal Between The Over Ground Wire And Armor Rod And Analysis Of Factors

The occurrence of the overhead ground wire breakage accident may cause large area power failure of power grid and serious economic loss.It even causes secondary disaster and threats personal safety.Currently,most of the studies about the ground wire breakage focuses on stress analysis and fatigue wear.However,mechanical degradation and even fusion of the ground wire in suspension string occur because of high temperature,which is also the main reason.The contact terminal between the ground wire and armor rod in suspension string is one of the main position of breakage.Thus,it is important to accurately calculate the diffusion resistance,which is used to characterize heat source of contact terminal,for practical application and theoretical research.Firstly,distribution characteristics of contact points between the ground wire and armor rod is analyzed in this article.According to the distribution characteristics of contact points,a 3D electromagnetic field simulation model of contact terminal was established by Finite element simulation software COMSOL.Current density distribution and diffusion resistance of contact terminal were calculated and analyzed.A calculation method of radius of the cylindrical conductive bridge model was proposed combining steady-state temperature rise experimental data and simulation data of contact terminal.The established simulation model was verified and analyzed by conducting a diffusion resistance measurement experiment of contact terminal.The effect of relative permeability of material steel and twisting parameters of stranded wires on diffusion resistance of contact terminal were investigated respectively.The research result can provide new ideas for optimal design of connection structure of the suspension string.