Experimental Study of the Discharge Area of Soil Breakdown Under Surge Current Using X-Ray Imaging Technology

Study on Structural Parameters and Analysis Method of Soil Successive Impulse Discharge Channel

“…The position of the critical breakdown electric field strength value E C in the development direction of the discharge channel was taken as the growth limit of discharge channel in the time step, ∆t. According to the experimental images and the research results in literature [1,2,18,20,21], we analyzed the structural characteristics of the discharge channel. Generally, the diameter of lightning discharge channel in the soil is several centimeters.…”

“…Soil is the most important medium in the grounding system [1][2][3][4][5]. Its discharge characteristics directly affect the lightning strike performance of grounding devices [6][7][8].…”

“…In order to solve the problems of traditional methods in changing the discharge environment as well as incomplete observation and high cost, the literature [1] proposes the use of X-ray transmission imaging technology to carry out non-intrusive imaging observation on the single impulse discharge channel in soil and obtain a gray-scale image that can reflect the structural outline of the discharge channel. The discharge channel is imaged from three perspectives (front view, side view and top view), and its 3D spatial structure is synthesized by using the boundary in the three views.…”

“…A variety of soil discharge models have been proposed, such as the hemispherical structure model [22], cylindrical structure model [23,24], segmented cylinder model [25] and multizone model [26]. The characteristic parameters of lightning discharge in soil are calculated based on the discharge channel structure in literature [1,2,7], and the transient analysis model of the grounding system is established. However, the existing models are generally based on the assumption of discharge current being uniform in each direction, without considering the underground discharge channel, which is inconsistent with the observation results of soil discharge with a centralized discharge channel.…”

Observation and analysis of the sparkover around grounding electrode under impulse current

“…Victor and Cabrera presented a method that used X‐ray sensitive films to investigate the discharge in sand, and reached the conclusion that the discharge shapes were mainly dependent on particle size and impulse polarity [9]. This method was also used by many other researchers [10–12]. Song et al [13, 14] used conducting paper to trace the propagation channel of impulse currents, and proposed a method to predict the characteristics of lightning breakdown channels in soil.…”