Research On Lightning Discharge Current Model

The lightning discharge is a phenomenon of instant air discharges in the nature.Strong current, high temperature, electromagnetic field and shock wave aregenerated during the process. At the same time, there are many other physicalphenomena, such as electricity, light, and sound. These physical effects result incasualties, structure damages, forest fires, and interfere with the communication andelectrical systems, worse still, lead to the interruption of them. As the rapiddevelopment of electronic communication, the losses caused by lightning will moreand more serious. At the end of20th century, lightning hazard was listed as one ofthe most ten serious disasters in the activities of the International Decade for NaturalDisaster Reduction of the United Nations Organization. As China’s vast territory,thunderstorm activity is also complicated and changeable. The overall distributionpattern: southern higher than northern, coastal higher than inland, mountain areashigher than plain. In the same region, the change is also affected by the topography,geology and climate. The lightning distribution is so complex that further research ofit is necessary for each area. Only in this way can we find the lightning protectionmeasures depending on different local conditions. And then, the lightning disastercould be reduced to the minimum degree.Lightning current is the most important parameter in studying lightningdischarge, and the current amplitude and waveform are important factors in thelightning protection design engineering. Meanwhile, from the discharge current data,we can get the total charge, energy, electromagnetic field and other relevantparameters of the lightning. These parameters give important guiding significance tothe design of radio communication system. So the analysis of lightning current is thepriority work to the study of atmospheric lightning discharge process and is also thebasis of studying lightning protection.Lightning current model is involved in the study of lightning discharge current.Many of the existing lightning current models contain only two parameters, wave tail time and wave head time. While other current parameters such as lightningchannel radius, velocity of the return stroke and soil resistivity, have relationshipwith lightning current. Therefore, we need to find new model which can betterreflect these trait to help the further analysis and research of lightning.The main work of this paper is as follows:1) Firstly, we introduce the characteristic of the formation and discharge oflightning, and then analyze the parameters of it.2) Compare to the existing model, combine with the lightning channel radiusand velocity of the return stroke, we explore the relationship betweenlightning discharge and these elements, and put forward the velocity-radiusmodel. This model not only accords with the basic law of lightning, but alsoreflect the quantitative relationship of the lightning discharge with aboveparameters well.3) On the basis of the velocity-radius model, we go on exploring therelationship of the soil resistivity and lightning discharge, finally proposethe resistivity model, and verify the applicability of the model. This modelcan manifest the lightning discharge with regional trends, and provides newreference data for communication and lightning protection system.