New Digital Simulation for Ground-Mode Switching Surge Response of EHV Transmission Systems

A method is developed which allows a digital simulation for ground-mode switching surge response when the transmission line has a step source. First, general Maxwell\´s equations are used in a basic theory to calculate the exact and complex results. New approximations are then introduced to get simpler expressions of the linear charge of the line. The equations of the simulation are now obtained. The digital simulation is based mainly on the complicated property "the more the ground-mode propagates, the more its delay increases." Other known properties are not compromised in the simulation. Formulas are presented which permit the calculation of the time-variable additional delay. Curves given by simulation are presented which can be compared with that given by calculation or that obtained by test oscillograms. When the ground mode is simulated, time delay method can be used.