Coupling of electromagnetic pulses created by a nuclear explosion on the ground with overhead power cables

Finite difference, frequency, and circuit simulation methods were used to study the effects of low altitude nuclear explosions on overhead electric power lines. Temporal evolution of currents in protection devices and energy dissipated in the varistors are compared for the three methods. Good agreement is obtained, especially for temporal evolution for times 1 msec. Instability appears in the current curves around 4 msec due to the sudden drop in the bipolar field. Interference increases relatively slowly (100's of msec) since the highly conductive plasma between the ground and the cables provokes returns to the ground.