火焰中颗粒对间隙放电特性的影响

Influence of Particles in Flame on the Characteristics of Gap Discharge

森林火灾易导致输电线路间隙绝缘强度下降,造成间隙放电而发生跳闸故障,严重影响电网的安全稳定运行。间隙击穿受火焰温度、带电粒子、颗粒与灰烬等的影响。为此,通过模拟山火研究了导线-板间隙在典型植被火焰条件下的击穿特性和火焰中颗粒对间隙放电特性的影响。进行了颗粒对电场畸变仿真研究,详细分析了火焰条件下颗粒触发间隙放电的机理。结果表明:在火焰条件下的颗粒触发放电特性和空气条件下有明显的不同,灰烬在山火条件下触发间隙放电具有倍增效应,能导致间隙因绝缘强度发生剧烈下降而击穿,击穿电压最多将下降为原来的1/10。

Bush fires easily lead to the decline in insulation strength of transmission line gaps and then trigger discharges and line trips, which seriously affect the safety and operation of power grids. Flame affects the gap breakdown in aspects including flame temperature, charged particles, ashes, and so on. Therefore, we experimentally investigated the break down characteristics of a wireplate gap under fire conditions, as well as how they are affected by the particles in the flame through simulations. We also analyzed the electric field distorted by the particle through simulation, so as to explain the mechanism of the particles in flame triggering discharge in the gap. The results show that the particlestriggered dis charge characteristics in the presence of flame is obviously different from that in air： ashes trigger discharge under vegetation fire conditions with a multiplying effect, i.e. the clearance insulation strength will sharply decrease by 10 per cent of a breakdown voltage.