3D Channel tortuosity of long air gap discharge

The geometric form of the leader trajectory is an interesting aspect of long air gap discharge research. In this paper, the 3-D discharge channel tortuosity in 3m rod-plane gaps is obtained by following steps: Firstly, using two static cameras fixed orthogonally to record the face photo and the side photo of the discharge channel. Secondly, the 3-D discharge channel is reconstructed by employing image recognition technology. Thirdly, the discharge channel tortuosity in two-dimensional space and three-dimensional space are derived respectively, which satisfied the Gaussian distribution law. The statistical results indicate that the channel tortuosity will be conservatively estimated by using a two-dimensional method. Statistical results of the channel tortuosity with three-dimensional method indicate the following conclusions. The angle between the discharge channel segments and the gap axis meets the distribution of rational function and its average value and standard deviation is 23.8° and ±19.0° respectively; the angle between the adjacent channel segments also meets the distribution of rational function, and its average value and standard deviation is 13.3° and ±9.9°.