Abstract
In this paper a method for a transient analysis on the multi-circuit overhead transmission line with different voltage levels (EHV and HV) is presented. The influence of inductive and capacitive couplings between the parallel circuits placed on the same tower is studied. The transmission line model consists of mutual coupled two-port cascades which can be described by a system of ordinary differential equations (ODE). This system has been solved numerically in MATLAB, the obtained results provide the time distribution of currents and voltages in all conductors along the transmission line. The presented algorithm allows solving various types of transients which can occur during switching off- and on-operations, shortcircuits etc.