Transmission Capacity of Gas-Insulated Power Lines Laid in Earthen Trenches

Abstract

One of the main problems in electrical supply for large cities is the absence of corridors for overhead transmission lines. This problem can be solved by using gas-insulated lines (GIL) laid in earthen tranches. With earthen deposition, the transmission capacity of GIL will be affected by the depth of deposition and by the temperature and thermal resistance of the soil. Amethod is proposed for calculating the long-term permissible current of an underground GIL that takes the external conditions into account. Calculations for a specific GIL design are reported and the results are analyzed.