Abstract:

The huge power produced by high altitude nuclear explosion (HEMP) can be coupled into civil air defense shelters via long conductors (for example,overhead power and communication cables),resulting in the damage of power or electric equipments connected with them.The transmission line model above lossless ground is used in this paper.The coupling characteristics between HEMP and parameters including the length and height of overhead lines,load impedance,and ground soil conductivity are obtained by numeric simulation,which will provide the reference for electromagnetic pulse protection of civil air defense shelters.Calculation shows that under the illumination of HEMP,the amplitude of induced voltage produced in the load of overhead cables ranging from 50 m to 1 km can reach up to tens of kilovolts to hundreds of kilovolts with a rise time of induced voltage of about 20 ns.

Key words: HEMP;overhead cable;coupling;soil conductivity;lossless transmission lines