输电线路是输电网络的重要组成部分。然而,电网输电线路山火频发,严重威胁输电线路的安全运行,因此研究输电导线在山火过后的力学性能特别是疲劳寿命尤为重要。考虑到导线在微风振动中的疲劳破坏主要由其拉伸力的变化引起,为确定山火过后输电导线的力学性能特别是疲劳性能的变化情况,利用恒温管式电阻炉模拟不同的架空输电导线(钢芯铝绞线)受到不同温度的山火烧烤,然后对冷却后的单丝导线进行疲劳拉伸试验,得到疲劳拉伸破坏次数随退火温度变化的规律,并与新导线和真实山火后的导线进行对比。试验结果表明:导线的疲劳极限随着退火温度的增加而减小;退火温度大于 250 ℃时,导线的拉伸循环次数急剧下降;退火温度大于 350 ℃时,拉伸循环次数趋于稳定。研究结果可为输电线路发生山火情况下的安全运行提供参考。
Transmission line is the important equipment to transport electrical energy through power grid. Mountain fires are frequent events in recent years, which severely damages the safe operation of the high voltage transmission lines. Therefore, it is very important to study the mechanical characteristics of transmission lines after mountain fire. Based on the simulation test of transmission lines in the mountain fire, we studied the effects of the annealing temperature on the fatigue of overhead transmission lines. The fatigue failure of the transmission lines in aeolian vibration was reflected in the continuous axial fatigue tensile state. First, we conducted an experiment by the thermostatic tube X resistance furnaces to stimulate different transmission lines (JL/G1A-400/35, JL/G1A-300/25, JL/G1A-240/30, JL/G1A-300/40) burned in the mountain fire at different temperatures. Then, we carried out a fatigue tensile test on the single transmission line, and found that the frequency of fatigue tensile failure was correlated with temperature. Furthermore, we compared the data between new transmission lines and those burned in an actual mountain fire. Finally, we proposed reference for the protection of transmission lines in a mountain fire and prevention against being burned. The results showed that the fatigue limit of wires was reduced with the rise of the temperature. When the temperature was between 250 ℃ and 300 ℃, the tensile cycle times deceases sharply;when the temperature is above 300 ℃,it tended to be stable.
Chinese Journal of High Pressure Physics
overhead line conductors