Research On Coupling Simulation Of Cables Against Electromagnetic Pulse

System interconnection cables are widely used, which cause the problem of coupling from electromagnetic field to cables. In case cables are under the electromagnetic pulse(EMP) radiation, electromagnetic energy would get into the system through cables, which can cause damage to the fragile electronic system. To guarantee working normally even interfered, it is necessary for sensitive electronic systems to be reinforced. Electromagnetic hardening design must be on the base of coupling quantity and coupling rules. Based on the theory of electromagnetic field and the transmission line equations, this paper details the modeling and computing problem of the single loop, the multi-line loop and the shielded cable, different numerical example is given, and provide reference for electromagnetic reinforcement design in engineering. In this paper, we study the electromagnetic pulse coupling simulation of cables, the main results obtained as follows:1.Based on the transmission line equation of single loop, this paper respectively researches on the effects of the length, height, angle of incidence and wire diameter on the quantity of coupling. The following conclusion is obtained by modifying the previous. Other cases being constant, the cable length within 0.1 m to 6 m, coupling quantity increases with the increase of line length; cable height within the range of 0.25 m to 8 m, coupling current increases with height. At the same time, this paper studies the amount of high-altitude nuclear electromagnetic pulse E2 and E3 phase to coupling quantity of cables. And the conclusion is obtained that as protection design of the E1 phase in high-altitude nuclear electromagnetic pulse, E2 and E3 stages can be taken into consideration.2. This paper presents a calculating method of the inner conductor coupling calculation. This method establishes coupling equation according to the characteristics of the shielding layer inside and outside circuit. After a reasonable simplification, nonhomogeneous equations of the inner loop can be changed into ordinary coefficient equations, and gradually deduce, eventually calculation formulas are gained. On the base of the coaxial line parameters to calculate, with the axis of the current distribution on the conductor at 1 MHz is received, and the core terminal position of time-frequencydomain coupling current and shielding layer shielding effectiveness are calculated respectively. The rationality of the method is validated by CST software simulation. This method provides a way to calculate the amount of coupling in coaxial conductor in engineering.3.This paper abstracts the actual circuit coupling calculation model through the analysis of USB. By CST software simulation, the model when there is no shielding layer and a shielding layer in the amount of coupling is obtained, and the conclusion is obtained that the reference current is higher than the differential line current in conductor multiple loops consisted by difference line and the reference ground line and that reference ground line should consider mainly in the protective design; the conductor cable shielding layer can make coupling current of the core wires significantly reduced, to achieve the level of the equipment tolerated or protected.