Interaction of multi-circuit overhead transmission lines of different voltages located on the same pylons

Abstract

The sharing of the routes for transmission overhead lines operated at different voltages and frequencies is a popular technical solution. Often the circuits of extra high and high voltage lines are installed on the same towers. This causes the electromagnetic interaction between corresponding power transmission systems. Earth fault currents and neutral point displacement voltages can be increased in electrical networks with resonant earthed neutral due to the electromagnetic influence from parallel located power transmission lines. Theoretical mechanism of the interaction, some practical examples based on investigations in German transmission networks and possible measures for the reduction of negative influences will be considered in the offered paper.