Analysis Of The Breeze Vibration Fatigue Life Of Overhead Conductor Considering Temperature Stress

Overhead transmission lines,as the main carrier for the transmission of electrical energy,are the main components that ensure the safe operation of the power system.Due to the conductor’s running with electricity,the temperature field generated by the current will change the stress distribution of the wire,and the stress distribution inside the wire will be more complicated under the condition of the breeze vibration,however,the existing mechanical properties of conductor and fatigue damage analysis rarely consider the influence of temperature,and these have a very important influence on the safety design and anti-fatigue performance of the conductor,therefore it is necessary to further study.Based on this,this article takes the commonly used LGJ300/50 steel-cored aluminum stranded wire as an example to study the influence of radial temperature field and temperature field on the mechanical properties of the conductor and the influence of radial temperature difference on the fatigue life of the conductor when the electrified conductor is in the aeolian vibration state.The main research contents and conclusions are as follows:(1)A 2D model of the LGJ300/50 wire was established.Ansys Fluent was used to analyze the temperature field when the electrified conductor running.The simulation results were compared with the theoretical values of the IEEE standard to verify the correctness of the model;on this basis,the effects of different current carrying capacity,different wind speeds,and different ambient temperatures on the temperature field were analyzed.The analysis shows that the increase of the ampacity and the ambient temperature and the decrease of the wind speed make the average and radial temperature difference of the conductor increase,and the radial temperature difference reaches a maximum of 8.94°C.(2)The 3D beam element was used to establish the layered model of LGJ300/50 wire,and compared with the theoretical results,the correctness of the wire model was verified.On this basis,the force characteristics of the wire in the consideration of the temperature influence are analyzed.The influence of wind speed,ambient temperature,ampacity and radial temperature difference on the stress distribution of the strands in each layer of wire is considered separately,and the influence of radial temperature difference on the outermost strand of the wire.(3)This paper systematically introduces the whole process of predicting the aeolian vibration fatigue life of the wire with considerating the influence of temperature field,based on Miner’s linear cumulative damage theory,combined with the wind speed and wind probability distribution,and using the method of combining the temperature and the principle of energy balance,the influence of radial temperature difference on the aeolian vibration fatigue life of the wire was studied.