输电线路走廊典型植被火焰绝缘特性测量与分析

Insulation characteristics measurement and analysis of the typical vegetation in the corridor of the transmission lines

山火条件下输电线路间隙的绝缘强度大幅下降,导致线路跳闸事故频发,给电网的安全稳定运行带来了严重影响。文章选取了输电线路走廊易引发线路跳闸的3种典型植被,对其火焰的绝缘特性进行了试验测量,并分析了植被火焰绝缘强度的影响机制;研究结果表明,在植被燃烧强度较大时,3种植被的火焰电阻率均较小,其中,杉树枝的最小,为3 kΩ·m,杉树干的最大,也达到30 kΩ·m,远低于纯空气间隙的绝缘强度;植被火焰的绝缘特性与火焰高度、温度、烟尘浓度、灰分含量等因素有关,而当火焰温度较低时,火焰高度与燃烧强度对植被火焰的绝缘特性影响较大。因此,控制输电线路走廊植被的高度和密度可以从根本上减少山火导致线路跳闸事故的发生。

The insulation strength of the transmission lines gap has a significant decline under the wildfire,then leading to the frequent line tripping accidents,which has a serious effect on the safe and stable operation of the grid.Three kinds of typical vegetation which can easily lead to the line tripping were selected in this paper,and the insulation strength of the vegetation flames were measured,meanwhile,the influence mechanism of the insulation strength of vegetation flame has been analyzed. The results show that,the resistivity of the three vegetation flame is small under the large burning intensity. Among them,fir branch is minimum,for 3 kΩ·m,and fir body is largest,reached to 30kΩ·m,the insulation strength of which are lower than pure air gap. The insulating properties of vegetation flame are related with the flame height,temperature,smoke concentration,ash content and other factors,while the flame height and burning intensity have a greater impact on the insulation characteristics of vegetation flame when the temperature is lower. Hence,controlling the height and density of vegetation in the transmission line corridor can reduce the accidents of line tripping under wildfire radically.