Suppression of Cable Sheath Current Using Ferrite Magnetic Rings

To suppress both the steepness and the amplitudes of the cable sheath current induced by an incident high-altitude nuclear-burst electromagnetic pulse, this paper adopts a suppressing method that uses ferrite magnetic rings installed on the shielded cable. Taking into account the material characteristics of the magnetic rings, a nonuniform transmission-line model is presented in the frequency domain for evaluating the suppressing effect of the magnetic rings, using the inverse fast Fourier transform, the terminal response in the time domain can be obtained. First, the impact of the ring cluster length and its installed position on the load cable sheath current are acquired. Then, the relationship between the suppressing effect and the material characteristics is discussed. Finally, the suppression mechanism is analyzed. The validity of the proposed model is verified by simulation, providing guidance for magnetic-ring-type selection and saving the expenditure of the experimental study.