Surge behavior at the discontinuity of a vertical line over the ground

This paper discusses the surge propagation at the discontinuity of a vertical line over the ground. Similar to a traditional transmission line, surge transmission at the discontinuity can be determined by its surge impedances. However, the surge impedances are different from the characteristic impedance of the transmission line. They respond differently to incident, transmitted and reflected waves, and vary with time. In this paper, these surge impedances are discussed in detail, and the methods for impedance evaluation are presented. The formulas of voltage and current transmission coefficients at the discontinuity are presented. A numerical example is presented to illustrate the surge impedances of a vertical line and to verify the formula of the transmission coefficients at the discontinuity.