爆炸气流灭弧试验与灭弧温度仿真分析

Analysis of Explosion Airflow Arc-extinguishing Test and Arc-extinguishing Temperature Simulation

采用爆炸气流灭弧是一种最新的防雷方法。为研究爆炸气流灭弧防雷间隙灭弧暂态过程，对35kV爆炸气流灭弧间隙进行10kA工频电流灭弧试验，试验表明电弧在爆炸气流的强烈扰动下迅速被拉长截断，灭弧时间约为4ms。同时根据电弧熄灭的温度判据（即当故障电弧温度降低到3000～4000K时熄灭）利用有限元计算软件FLUENT对气流和电弧耦合作用暂态过程中的电弧温度进行模拟仿真。由仿真结果可知，在高速爆炸气流的作用下，电弧能量变弱，温度呈非线性下降，在4ms时降至熄灭的临界值熄灭。为了验证试验与仿真的实际效果，进行了爆炸气流灭弧防雷间隙实地运行试验。运行试验表明：爆炸气流灭弧防雷间隙能够降低雷击跳闸率90％以上，安装灭弧间隙后的输电线路既限制了雷击过电压，又能显著降低雷击事故率，具有良好的实用性。

Extinguishing arc with explosions airflow is a new concept of lightning protection. To study the transient process of explosion airflow arcing lightning protection gap, 10 kA power frequency current arc-extinguishing tests are carried out for 35 kV air-blast arc-extinguishing gap. The tests show that the arc is quickly elongated and truncated under strong disturbance of explosions airflow, and arc-extinguishing time is about 4 ms. According to the criterion of arc-extinguishing temperature（the arc is extinguished when the fault arc temperature drops to 3 000-4 000 K） at the same time, the finite element analysis software FLUENT is used to simulate arc temperature in transient process of the airflow and the arc coupling effect. By analyzing the change state of arc temperature, it is found that arc＇s energy and temperature nonlinearly decline under the action of high speed explosion airflow, and the arc is extinguished when the temperature fells to a critical value in the 4 ms. Test running effect shows that explosion airflow arc-extinguishing lightning protection gap can reduce the lightning trip-out rate of more than 90%. The transmission line not only limits the lightning overvol- tage already, but also can significantly reduce lightning accident rate after installing arcing gap. So explosion airflow arcing lightning protection gap has a good practicability.