High-capability applications of long gas-insulated lines in structures

This paper deals with the possibility of installing gas-insulated transmission lines (GILs) in dedicated or shared structures. The applications involve railway galleries (both in the proper galleries and in service or pilot tunnels), highway networks, and gas lines. The high GIL power capability together with very low power losses configures these applications as high transmission efficiency corridors. Some issues of this application will be shown in this paper (steady-state regime of the line, voltage drops, power losses, voltage unbalance factor, ampacity, electromagnetic field impact, and limit lengths). Moreover, this paper discusses the necessary studies to be carried out and the problems that have to be faced in order to develop this kind of application toward a feasible technical solution.