Research On Simulation And Measurement Of Lightning Electromagnetic Field In Buildings

Along with the ceaseless construction of intelligent buildings and the extensive application of electronic application,the electromagnetic effect of lightning on buildings and the lightning protection work have been highlight of people.In the lightning protection design,a cage-type lightning protection system composed of reinforcement would be selected by modern building generally.The leading role is to induce the lightning current to reach the aim of protecting the building.Lightning would form a powerful transient current in the lightning protection system when it shocks the building,so as to form electromagnetic interference.Therefore,analysis of transient electromagnetic effect in lightning protection system has been a critical study topic in the field of lightning study.The danger of direct lightning is triggered by a lightning current so that the paper would analyze the relevant parameters of lightning current.There is a simulation on the three frequent lightning current models,and there is an analysis on the spectrum characteristics of lightning current.Then,a simplified frame model of lightning protection network is established according to the actual lightning protection system of buildings.There is a rapid calculation of electrical parameters between conductors on building frame,which does improve the calculation efficiency compared with other calculation methods.According to the transmission line coupling network model,the node voltage and conductor current of building lightning protection system are calculated.The transient response of lightning protection system in time domain is calculated with Fourier transform technology.To improve the calculation speed of the system response,frequency domain extrapolation is introduced to enhance the speed obviously.The distribution of transient magnetic field in buildings and the induced electromotive force produced by rectangular coil in room are calculated after gaining the distribution of conductor current on the frame of lightning protection system,which would provide evidence to study the electromagnetic interference of lightning to electronic equipment in buildings.Then,based on the theoretical work above,there is design of calculation software and algorithm verification.To improve the performance of lightning protection facilities,there shall be record and analysis of lightning current,so it needs the corresponding measurement method of lightning current.Hence,it is introduced to use Roche coil as sensor to measure thelightning current.Meanwhile,there shall be analysis of the necessity of lightning protection device test and the main content of the test to ensure the regular running of lightning protection device,so as to push the building system moves towards the direction of safety.