正极性雷电冲击电压下5m棒-板空气间隙放电特性试验研究

Experimental Study on the Discharge Characteristics of a 5 m Rod-Plane Air Gap Under the Positive Lightning Impulse

开展了正极性雷电冲击电压下5 m棒-板间隙的放电试验,同步测量获得了放电电压、放电电流和图像。根据放电不同阶段的电流特性,辨识了初始电流放电、二次流注放电和先导放电过程,并研究了电压幅值和电极形状对上述放电阶段的影响。试验结果表明,初始流注放电产生的空间电荷与电压幅值和电极曲率半径均正相关,其抑制作用使得流注起始时延的平均值近似为常数;二次流注的平均速度为700~1 060 cm/μs,其随着电压幅值的增加逐渐增大,而随着曲率半径的增大而减小;先导发展的平均速度为29~111 cm/μs,随电压幅值的增加线性增大,而随电极曲率半径增大有所降低。

Experiments are carried out in a 5 m rod-plate gap under positive lightning impulses, and the discharge voltage, discharge current and video image are recorded synchronously. According to characteristics of the discharge current at different stages, three main discharge phases are identified, which are the first streamer discharge, the second one and the leader discharge. The influences of impulse amplitude and electrode shape on the characteristics of each discharge stage are studied. The results show that the space charge generated by the first streamer discharge is positively correlated with the voltage amplitude and the radius of curvature of the electrode, and its suppression makes the average value of the initial delay of the second streamer is approximately constant. The average velocity of the second streamer is 700~1 060 cm/μs, which increases with the voltage amplitude, and decreases with the radius of curvature. The average speed of the leader is 29~111 cm/μs, which increases linearly with the voltage amplitude, and decreases with the curvature radius of the electrode.