Study On The Current Distribution Of Tall Buildings Under Direct Lightning Strike

Nowadays tall buildings are widespread. As the increase of the height of tall buildings,the damages from the direct lighting strike to the tall buildings are more and more serious.Therefore the study of lightning strike to tall buildings is important and urgency. This paperis focus on the lightning current distribution in the building structure for the study of thelightning strike to tall buildings.Scholars from the domestic and foreign countries generally used the circuit methodand the electromagnetic method to analyze the lightning current distribution in buildingstructure. In this paper, simulation software is selected to simulate lightning currentdistribution in building structure based on the finite element method. The lightning proofsystem model of the tall buildings is established according to the lightning protection normsof buildings. Firstly, the simulation control equations of the finite element are deduced,which can describe the mechanism of current distribution. Then the simulation model oflightning current is analyzed and determined according to the lightning protection norms ofinternational IEC62305. Three building models are established to do the simulationrespectively under different structures of down conductor. The multi-layer structure of thetall buildings made it is necessary to analyze the impact of the current distribution ondifferent floors of tall buildings. Grounding is also an important factor that affects thecurrent distribution of the tall buildings. Another content of this paper is to set the earthingelectrode into simulation. A hemisphere is designed as the earth, earthing electrode placedin the hemisphere of the earth in order to analyze the impact of the lightning currentdistribution to the tall buildings.Based on the simulation results above, the magnetic field distribution is analyzedwhen strike by lightning under the three different down conductor structures. Finally,according to the law of electromagnetic induction, the mutual influence of the inductivecurrent between the down conductors is analyzed.