Study On Stress Characteristics Between Transmission Conductors Under Tension Load

The normal and stable operation of the power grid is related to the national economy and people’s livelihood.As an important part of the power grid system,transmission lines are bound to receive widespread attention.Since the damage of the transmission line is an important factor affecting the safety of the transmission line,it is of great engineering significance to study its damage mechanism.Steel core aluminum stranded wire(ACSR wire)is the most widely used type of transmission wire.Tensile load is the most common load form during the operation of the wire and has an important influence on the overall mechanical properties of the wire.The actual working conditions found that,due to the stress distribution of the strands,wire breakage and strand breakage occurred mostly in aluminum strands.In this context,this article conducts research on the inner strand stress of power transmission lines under tensile load.The main research involves the following:(1)A mechanical analysis was performed on the wire under tensile load,and the mechanical equilibrium equation of the wire strand was established,and the relationship between the tension and the wire stress was obtained.The contact pattern between adjacent strands of the steel core aluminum stranded wire After analysis,the formula of the contact stress in the contact area is given,and the position of the contact point is deduced based on the wire structure.(2)In order to solve the problems of complex models and difficult to measure the inner layer strain in traditional research,a new modeling and analysis method is proposed,which uses the cyclic spiral symmetry of the wire to simplify each layer of strands into three adjacent ones The strands are analyzed and studied.The abaqus software is used to conduct a finite element research on the proposed modeling and analysis method.The validity of the analysis model is verified by comparing the simulation results with those in the literature.At the same time,this analysis method was used to establish a JL/G1A-630/45 steel core aluminum stranded wire model and researched it.The results show that the stress of the inner layer of the aluminum strand is greater than that of the outer conductor.Large,the contact area is elliptical,and there is a stress concentration phenomenon in the contact center,which easily causes the damage of the wire.(3)In order to realize the test of ACSR wire interstrand stress and dynamic and static mechanical experimental analysis,a tension test bench for tensile wire strand was designed.The test lead was used to conduct experimental research on the aforementioned wires.The fiber grating sensing system was used to collect the strain signals,and the wire tension-strain data was obtained.The test results were compared with the finite element results and theoretical calculation results,which verified the proposed Analytical modeling method.It provides basic conditions for further research.