植被火条件下导线-板短空气间隙泄漏电流特性研究

Study on Leakage Current Characteristics of Conductor-Plane Short Air Gap under Vegetation Fire Condition

为研究植被燃烧火焰条件下空气间隙泄漏电流特性及其对间隙放电特性的影响,开展不同植被燃烧条件下45cm导线-板短空气间隙的放电特性试验,分析植被火焰中电荷产生的过程,研究不同植被火焰条件下间隙的泄漏电流特性和导线-板间隙的放电特性,对比植被不同燃烧强度时间隙泄漏电流特性。结果表明,在12kV的正极性直流电压下,杉树枝火焰间隙泄漏电流峰值为27mA,秸秆火焰间隙仅为8.3mA;杉树枝火焰下间隙的击穿电压约为秸秆火焰条件下的44%,间隙泄漏电流与击穿电压具有负相关关系;火焰条件下间隙泄漏电流存在明显的极性效应,正极性电压下泄漏电流大于负极性;间隙中植被燃烧强度增大时,间隙击穿电压显著下降,击穿前间隙中已经形成相对稳定的泄漏电流。

In order to study the leakage current characteristics of air gaps and its effect on gap discharge characteristics under flame condition,the discharge experiments of 45cm conductor-plane gap under different vegetation flames were carried out.The process of charge generation in vegetation flames was analyzed,the leakage current characteristics and the discharge voltages of the gap were discussed at the same time.The leakage current characteristics of the gap under vegetation flame with different combustion intensities were compared.The results show that under 12kV positive DC voltage,the leakage current peak value of the gap under fir branch flame is 27mA,and the straw flame is only 8.3mA;the breakdown voltage of the gap under the fir branch flame is about 44%of that under the straw flame condition.There is an obvious polarity effect of the leakage current under the condition of flame,and the leakage current under positive voltage is larger than that under negative polarity.When the burning intensity of vegetation in the gap increases,the gap breakdown voltage decreases significantly,and a relatively stable leakage current has been formed in the gap before the gap breakdown.Keywords:Vegetation flame,charges,leakage current,polarity effect,combustion intensity breakdown.