Modelling of the transients on the multi-circuit EHV/HV overhead transmission lines

This paper describes a method for a common transient analysis for the multi-circuit overhead transmission line. The presented algorithm is based on two-port approach, where the phase conductors and earth wires are modelled by inductive and capacitive coupled cascades of two-ports. For a considered network model, a system of ordinary differential equations (ODE) has been formulated and it has been solved in MATLAB. Obtained results provide the time distribution of currents and voltages in all conductors. In this paper a system with four three-phase system of two voltage levels (EHV and HV) has been analysed. The performed calculations deal with short circuits and the necessary switching. The optimization of the creation of the two-port model has been discussed.