Which type of underground transmission uses gas insulation?

Gas Insulated Lines (GIL) are specifically designed to utilize gas insulation as a means to operate high voltage transmission lines in underground environments. The technology behind GIL employs an insulating gas, typically sulfur hexafluoride (SF6), which has excellent insulating properties and allows for effective and efficient transmission of electricity while significantly reducing the space required compared to traditional air-insulated or fluid-filled systems.

This approach minimizes the risk of electrical breakdown and enhances reliability, particularly in areas where space is limited or where environmental conditions could complicate the use of conventional cables. GIL systems are increasingly favored for their ability to maintain high levels of performance with reduced footprint and easier integration into urban environments.

The alternatives, while all valid types of underground transmission systems, rely on different insulating methods. High Pressure Fluid Filled (HPFF) systems use fluid to provide insulation, and Self Contained Fluid Filled (SCFF) systems also utilize liquids for insulation. High Pressure Gas Filled (HPGF) similarly employs gas but is distinct from GIL in its configuration and operational principles. Thus, GIL stands out specifically for its gas insulation technology.