The breakdown current, current impulse velocity, and E-field in air gap discharge are of interest among researchers on high-voltage engineering and lightning study. It is the breakdown current and current impulse velocity that govern the radiated E-field property. The current impulse velocity, however, is not well addressed in the literature. In this paper, we use a self-developed high-speed observation system, a Rogowski coil, and a transient E-field sensor to measure the current impulse propagation velocity, breakdown current, and vertical E-field in the rod-to-plane discharge after the air gap breakdown under dc voltage. From the time difference of arrival of light signals in different receiving channels, the resultant current impulse propagation velocity is measured as 6.81 ± 0.57 × 106 m/s. Meanwhile, the breakdown current at the bottom of the grounded rod electrode has a peak value of approximately 1.3 kA and 10%–90% rise time of 40 ns, and the transient vertical E-field at ground level has an amplitude of approximately 15 kV/m and 10%–90% rise time of 64 ns. In addition, according to the measured breakdown current and resultant current impulse velocity, the vertical E-field is computed by using the finite-difference time-domain method in the two-dimensional cylindrical coordinate system. The computed vertical E-field agrees well with the measured E-field, validating our measured current impulse velocity. Besides, the computed horizontal E-field and azimuthal H-field are also analyzed. Finally, the influence of current impulse velocity on the vertical and horizontal E-field and azimuthal H-field is discussed.

中文翻译：

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气隙放电击穿电流、速度和电场的实验与仿真研究

高压工程和闪电研究的研究人员对气隙放电中的击穿电流、电流脉冲速度和电场感兴趣。控制辐射电场特性的是击穿电流和电流脉冲速度。然而，目前的脉冲速度在文献中并没有得到很好的解决。在本文中，我们使用自主开发的高速观测系统、Rogowski 线圈和瞬态电场传感器来测量杆对平面的电流脉冲传播速度、击穿电流和垂直电场。在直流电压下气隙击穿后放电。从光信号在不同接收通道的到达时间差，测得的电流脉冲传播速度为6.81±0.57×106 m/s。同时，接地棒电极底部的击穿电流峰值约为 1.3 kA，10%–90% 上升时间为 40 ns，地平面瞬态垂直电场的振幅约为 15 kV/m 10%–90% 的上升时间为 64 ns。此外，根据测得的击穿电流和合成电流脉冲速度，在二维圆柱坐标系中使用有限差分时域方法计算垂直电场。计算出的垂直电场与测量的电场非常吻合，验证了我们测量的电流脉冲速度。此外，还分析了计算出的水平电场和方位角磁场。最后，讨论了电流脉冲速度对垂直和水平 E 场和方位 H 场的影响。