输电线路山火跳闸机理的模拟实验研究

山火发生时植被燃烧产生的高温火焰及烟羽流使架空输电线路的空气绝缘性能大幅降低,可能引发导线之间或导线对地面间的击穿放电现象,导致输电线路发生跳闸事故。选取正庚烷与木垛为代表性火源,模拟研究直流高压电在火焰中的击穿放电现象,测量了火焰温度和电阻参数,获得了不同火源条件下放电间隙的击穿电压,分析了火焰参数对间隙击穿场强的影响。实验结果表明,正庚烷和木垛火焰放电实验中,火焰高温和电导率是导致击穿场强下降的主要因素。此外,烟颗粒也会导致击穿场强下降。

Simulative experimental study on wildfire induced breakdown of transmission lines

High temperature flame and smoke plume produced by burning wildfire can weaken the air insulation strength of overhead transmission lines greatly, and may cause the discharge between the conductors or conductor to ground and hence the breakdown of the transmission lines. The present study used the n-heptane and wood crib fire sources to study the discharge of high voltage DC electrode in the steady burning flames. The temperature profiles and average resistances of the flames were measured and the breakdown voltages of gaps in different flames were obtained. The influence of flame parameters on the breakdown strength of gap was analyzed. The results show that, high temperature of flame and flame conductivity are the most important factors on the decrease of breakdown strength of gap in fires. Additonaly, smoke particles also decrease the breakdown strength.