Aeolian Vibration Monitoring And Fatigue Damage Calculation Of Overhead Transmission Lines

Transmission lines are complex system which made up of wires, armour clamp, insulator and tower together. In field environment, overhead transmission lines are vulnerable to strong winds, heavy rain, lightning and other natural disasters. Because our country has a vast territory, ice accretion on transmission lines usually causes great damage in winter in some areas. According to statistics, most accidents are the accidents caused by wind. Depending on the amplitude and frequency, transmission lines vibration can be divided into: vibration with high frequency but low amplitude, vibration with medium frequency and medium amplitude and galloping with low frequency but high amplitude. Among them, the high frequency vibration is also known as Aeolian Vibration. The probability of Aeolian Vibration is highest, and it has longest duration and greatest damage.A series of Aeolian Vibration calculation model is established by scholars at home and abroad based on the energy balance method and finite element method. The indoor vibration fatigue test is carried on the transmission wires before used to evaluate its fatigue status. But in view of the overhead transmission lines fatigue damage all the year round, the real-time monitoring and analysis is rather difficult.Contraposing the shortage of traditional aeolian vibration fatigue tests and models of transmission lines, and the problem of bad real-time and few monitoring parameters of monitoring system, the author concretely did the following work:(1) The fatigue damage calculation model based on Miner linear accumulated damage theorem is improved by means of analysising the influences of the tension of lines and different meteorological conditions on aeolian vibration fatigue damage. The line vibration curve integrated directly from the acceleration sensor recorded data will present a serious problem of baseline drift. Therefore, based on least-square theory, a new baseline correction method is proposed to eliminate effect on drifts, and then obtain distortionless vibration curve by twice integrations.(2) The aeolian vibration monitoring system of transmission lines based on embedded technology, ZigBee wireless network technology and sensor technology is designed. The system transfer real-time field data of meteorological factors, stress of conductor, monitoring node acceleration and field image to background computer. And then the field data is processed to monitor the real-time running state of transmission lines.The system running results show that monitoring data fitting track are in good agreement with the actual measured trajectory. The system can satisfy the needs of the real time monitoring on transmission line site and be well applied to the calculation of conductor fatigue damage.