Impact of Asymmetry of Over-Head Power Line Parameters on Short-Circuit Currents

Abstract

<span lang="EN-GB">This paper analyses the impact of asymmetry of over-head power line parameters on short circuit currents when three-phase fault and phase-to-ground fault occur. The calculation results with consideration of an asymmetry of the power line parameters are confronted with the calculation in accordance with the Slovak standard STN EN 60909 which does not consider asymmetry of equipment parameters in the power system. The calculation of short-circuit conditions was carried out for two types of 400 kV power line towers on which is a considerably different arrangement of phase conductors.</span>

The influence of ground wires on the resistance and reactance of high voltage overhead power lines

“…This current changes the total magnetic flux o f phase conductors, and thus their longitudinal impedance. This effect is most pronounced in asymmetric operating conditions o f OPLs [8], and especially in those cases where zero sequence currents appear in the phase conductors [9]. In order to find the current flowing through the ground wires, relationships for calculating the voltage of ground wires are used, where, in addition to the currents in the phase conductors and ground wires, their self and mutual impedances [10][11] also appear.…”