Loadability and Magnetic Field Characteristics of Advanced 7-Phase Overhead Conductors

Although, renewable energy sources present social and environmental advantages, several investments are needed in the electrical infrastructure with the aim of allowing better integration. Furthermore, due to the different locations of huge loads (mainly in the centre and north) and renewable energy sources (mainly in the south) in Italy, new technologies and solutions are needed to transmit power over long distances, while also addressing environmental concerns, including electromagnetic field emissions and visual interaction. In this context, the Italian Transmission System Operator -TSO, has recently introduced a new high voltage overhead line (OHL), so called "7-Phases". The "7-Phases" overhead lines enhance the power transmission capacity of existing ac double-circuit corridors while maintaining the same right-of-way. They also offer the added benefits of reduced magnetic field emissions, minimized visual interaction and increased transmittable power.

The paper aims to introduce the innovative "7-Phases" tower, designed to increase the transmittable power of existing ac double circuit corridors. The paper explores and compares the performances of "7-Phases" and double circuit towers, regarding primary constants, magnetic field emissions and loadability (i.e. maximum transmittable power as a function of line length).