Ricerc@Sapienza

We investigate the improvement of the lightning performance of overhead power lines through the use of additional ground wires placed below the phase conductors. The analysis of the electrical system is carried out through a method based on the conventional multiconductor transmission-line formalism. In the presence of a direct lightning, both the currents flowing in phase conductors and ground wires and the overvoltages across insulator strings can easily be evaluated. The main effects of such additional ground wires are here pointed out through an accurate numerical analysis.

The improvement of the lightning performance of overhead distribution lines, hit by direct strokes, is investigated considering the use of additional shield wires beneath the phase conductors. The frequency-domain theory of multiconductor transmission lines with periodical grounding is adopted permitting a rigorous evaluation of the phase and shield wire currents and of the overvoltages across insulators. These can be minimized by careful positioning of the underbuilt shield wires.

The proper monitoring and operation and maintenance (O&M) of solar photovoltaic (PV) systems are an integral part of the service tasks required to ensure long-term reliability and prolonged lifetime of the installation. In the recent years, with the end of the feed-in-tariff legislation, the PV stakeholders and operators shifted their focus from the design and construction of utility-scale grid-connected PV plants to the development of monitoring and more efficient O&M practices.

In high voltage transmission lines, the shield wires are often sectionalized for several reasons. This practice may have considerable effects on power line communications in multiconductor transmission lines. A careful simulation is performed in order to put in evidence the relevant channel features.