Technical comparison between a Gas-Insulated Line and a traditional three-bundled OHL for a 400 kV, 200 km connection

Aiming to explore the applicability of Gas-Insulated Lines (GILs) over long distances, in this paper we perform a technical comparison between a GIL and a three-conductor bundled, traditional overhead line (OHL), for a 400 kV, 200 km long connection. The technical comparison is based upon transmission capacity and power losses. We derive the transmission capacity of the two systems from the relevant loadability curves, for the selected line length L=200 km. For this length, OHLs loadability curves are normally determined by the voltage drop limit, ΔVMAX (i.e. the maximum voltage drop allowed across the line), whereas the GIL loadability can be determined – according to the selected GIL parameters – by the thermal limit. In addition to power losses in the conductors, Gil losses include losses in the enclosures. The results point out remarkable advantages for the GIL solution.