The HEMP response of an overhead power distribution line

Estimates of the transient voltage surges induced by a high-altitude nuclear detonation across a transformer in a single-phase distribution line are provided. A multiconductor line coupling model is used, along with a high-altitude electromagnetic pulse (HEMP) environment. Both the open-circuit voltage across the transformer and the loaded voltage are considered. To obtain reasonable data for the frequency domain analysis used, measured data of the pulse response of the transformer are used to obtain its input impedance in the required frequency range. Summary curves of the probability of exceeding voltage levels at the transformer are presented