Research on the Influence of Terrain Curved-Surface on Lightning Parameters

Lightning parameters are indispensable key parameters in lightning protection design. Based on the ground lightning data from the Hainan lightning location system in 2009, the relationships between lightning parameters (the average lightning current amplitude of total ground flashover, the proportion of positive and the negative flashover, and total ground flashover density) and terrain curved-surface parameters (slope, slope aspect, and slope position) are studied by means of GIS spatial analysis and mathematical statistics. Firstly, it is concluded that there is a cubic function relationship between the average lightning current amplitude of total ground flashover and slope. The proportion of positive flashover decreases with the increase of slope, and the distribution of total ground flashover density features U-shape with the increase of slope. The lightning protection should be strengthened for the transmission lines built on the mountain with the slope below 10° or above 48°. In addition, when the slope aspect is in the southwest direction, the average lightning current amplitude of total ground flashover and total ground flashover density are the lowest, while the proportion of positive flashover is the largest among all slope aspects. So some anti-backflashover measures should be taken for transmission lines built in the southwest slope aspect. Besides, the average lightning current amplitudes of total ground flashover are the largest and the total ground flashover densities are the highest in ridge and valley among all slope position. Some special lightning protection measures should be considered to be taken in ridge and valley.