Calculation and Assessment for HEMP Response of Overhead Transmission Line

The high altitude electromagnetic pulse (HEMP) generates induced voltage and current with high amplitudes and very steep front edges on transmission lines. The frequency domain chain parameter matrix method was adopted to model the HEMP responses of overhead transmission lines, the induced voltage and current of HEMP responses are calculated for the transmission lines with different voltage levels in combination with the impact characteristics of incident angle, ground conductivity and line length, and the HEMP impact on the overhead transmission lines are assessed. These could provide the basic data for developing protection measures for power grid.