Approximate Formulas for Surge Characteristics on the Transmission Line considering Series Resistance

Abstract

The series resistance of a transmission line in high frequency phenomena such as lightning surge becomes high due to the skin effect, and affects switching and lightning overvoltages in an electric power system. A number of transmission line models have been proposed to consider the frequency dependence of line constants. It is difficult to denote surge characteristics of a transmission line in time domain due to the existence of the series resistance. This paper proposes approximate formulas for terminal voltages on the transmission line in time domain. The approximate formulas are derived on the basis of the lattice diagram method. The expression of the approximate formulas is given by exponential functions, and is very simple. The formulas are useful for engineers to discuss many parameters and to understand simulation results for transmission line having high series resistance.