Numerical Simulation Of Development Process Of Double Grounding Lightning

Lightning is a common physical phenomenon in nature.Double grounding lightning is a special and more destructive lightning,which can produce two large span grounding points and discharge between cloud and ground through two branch channels.Due to the unpredictability,low frequency,short time and other characteristics of double grounding lightning,the observation data of double grounding lightning is still very scarce,and many physical problems such as its generation mechanism and development characteristics are still unclear.This paper attempts to simulate the development process of double grounding lightning by establishing theoretical model,and find some development characteristics and rules of double grounding lightning.The simulation results show that for each double ground lightning,the distance between the two grounding points is smaller than the height of the branch point from the ground.Statistics show that the average distance between two grounding points is about half of the height of the branch point,and increases with the increase of the height of the branch point.The formation of double grounding lightning has no much relation with the height of the branch point,and has a great relationship with the difference of the vertical distance between the two branches.The smaller the vertical distance difference between two branches of lightning,the greater the probability of developing into double grounding lightning.The probability of double ground lightning in our simulation is about 16%.The two branches of double ground lightning develop at almost the same speed to the ground.The results of some of our simulation are compared with those of the double ground lightning in nature.The results show that the two are in good agreement with each other,which shows the rationality of the model.This work will help to understand some physical characteristics of double grounding lightning in the development process,provide reference for the protection of this type of lightning disaster,and also provide some theoretical reference for the research of air bifurcated discharge in high voltage laboratory.