The Study On The Stress Of Wire Strands And Vibration Fatigue Life Of Overhead Conductor Under Operating Conditions

The overhead transmission line under the operating condition is a combination of the charged work,it has to bear the combined action of tension,breeze vibration and temperature field in a long time.Due to the existence of tension,the aeolian vibration fatigue of the conductor belongs to the fatigue problem under asymmetrical cyclic alternating stress,and the influence of the average stress on the fatigue life should be considered.Because the wire steel core and aluminum stocks of different linear expansion coefficient,each layer of the relationship between the stress and temperature is not same,so accurate analysis wires running temperature field in the stress distribution on the precise calculation of transmission conductor breeze vibration fatigue life is necessary.However,there is very little research on the effect of wire temperature on the laminar stress and the effect of the wind vibration,In view of this problem,the main work of this paper is as follows:Firstly,based on the layered structure characteristics of Aluminium Conductors Steel Reinforced(ACSR),stress mechanics balance equations established by wire deformation coordination condition of the wire wire stock layer in the role of tension and temperature of each strand layer,using ANSYS to establish the precise model of the wire,after loading compared with the theoretical value,and then verify the correctness of the theory.Analysis of the influence of temperature and radial temperature of the outer layer aluminum strand tension;and then analyzes the change of the conductor hanging points of the outermost layer of aluminum stocks due to changes in the temperature of the wire caused by stress.Secondly,this paper introduces the traverse breeze vibration mechanism,by studying the wire vibration when the input power,wires since damping power,using the energy balance method to evaluate the strength of transmission wire vibration,and then analyzes the wire tension,terrain and span of breeze vibration amplitude,the influence of temperature,wind speed is analyzed emphatically the influence of vibration of wire joint action.Finally,systematically introduces the detailed process to estimate service life of wire,wire wind direction,wind speed probability distribution is analyzed emphatically,and through the breeze vibration dynamic bending stress and the average stress of lead wire strands,solving the equivalent alternating stress amplitude of transmission line;Based on the combined probability of wind speed and wind direction,the average wind vibration time of the year is obtained.The fatigue life of transmission conductor is evaluated by means of the principle of Miner's linear cumulative damage and the s-n curve of the transmission line.The influence of wire tension,terrain and suspension height,especially temperature on fatigue life of transmission conductor is studied.