The Simulation Study Of Electromagnetic Field Around EHV Transmission Line Stroked By The Lightning

With extensive application of various electronic circuits and electronic technology in the fields of family, industry, traffic, national defence, Electromagnetic Interference (EMI) has already become the problem that must be considered in the design process of modern electrical engineering. Lightning electromagnetic pulse (LEMP) is so harmful that it has become a very important EMI source. LEMP affects the environment around the lightning channel, and when lighting strokes on the transmission lines, it can enlarge its effect area through the transmission lines. So it is important theory value and realistic significance to simulate, calculate and analyze the LEMP and to evaluate whether it satisfies the relevant environmental protection standard, which provides the basis for taking necessary countermeasures.This paper firstly introduces the FDTD method's fundamental principle with special emphasis in three boundary condition namely Mur second order, Berenger perfect matching layer and Gedney perfect matching layer. Then some key technologies using FDTD method to solve the electromagnetic radiation problem are expatiated when lighting strokes EHV transmission lines. Based on the algorithm thinking of the FDTD method, general algorithm program on electromagnetic radiation problem is given. Through the electric dipole source radiation models in three-dimensional space, its validity is tested and verified by comparison.Based on FDTD thin wire algorithm created by the integral form of Maxwell's equation group, equivalent idea, that is the equivalence of multihead wires with single wire, the model of EHV transmission line stroked by lightning is established. On this basis, the electromagnetic field distributing conditions around the EHV transmission line stroked by lightning and lots of numerical results are obtained. And the contrast with the result of Transmission Line Model (TLM) has explained the exactness of the simulation result of this paper. The field intensity distribution condition around the EHV transmission line stroked by lightning is preliminary analyzed in this paper. And the results have certain actual reference value.To sum up, applying FDTD method to simulate the electromagnetic field around the EHV transmission line stroked by lightning is feasible. Some valuable results have been obtained, and the application range of FDTD method has been extended.