Response of Overhead Cables to Low-Altitude Nuclear Electromagnetic Pulse

The coupling characteristics of overhead wires under high-altitude nuclear electromagnetic pulse (HEMP) have been extensively studied. However, the effects of low-altitude nuclear electromagnetic pulse (NEMP) on the field values at observation points vary with explosion height, yield, and ground medium, and the coupling characteristics of overhead wires under low-altitude NEMP remain unresolved. To address this issue, this article proposes a solution. First, the finite-difference time-domain (FDTD) method is employed within a rotated ellipsoidal-hyperbolic orthogonal coordinate system to solve Maxwell’s equations and the air ionization equation, thus obtaining the source field at the location of the overhead wires. Subsequently, these results are used as an excitation source to calculate the response characteristics of the overhead wires with terminal loads using transmission line methods. Finally, the impacts of factors such as explosive yield, altitude, ground conductivity, terminal impedance, and cable height on the terminal induced current of overhead wires located at the edge of the source region under low-altitude NEMP incidence are analyzed. This study provides theoretical support and reference value for the protective design of power systems.