IEEE C37.122.4-2016 pdf free
IEEE C37.122.4-2016 pdf free.IEEE Guide for Application and User Guide for Gas-Insulated Transmission Lines, Rated 72.5 kV and Above.
Cl(RE 218 provides comprehensive information about GIL(Koch [B351).M Subclauscs 4,2 through 412 provide a short overview ofGIL t’catures to I’arnilianze the reader with the characteristics of GIL.
The technology of GIL. is similar to gas-insulated substations (GIS). where a high-oltage conductor supported by insulators is positioned within a grounded enclosure and the remaining space between is filled with a pressuriied gas for electrical insulation, See Figure I for the internals of the GIl.. The support insulators are composed of composite cast resin material. The conductor of each phase is located within an aluminum enclosure. Sliding contacts provide compensation toriherinal expansion of the conductor. The enclosure expansion (i.e., in tunnel or trench installations) is compensated for by bellows assemblies. The GIL is diided along its length into separate gas compartments. (ill. dimensions are determined by the dielectric, thermal, and mechanical design requirements. (‘onductor and enclosure diameters and thicknesses, and gas composition and pressure. may be aried according to the application to provide an optimum solution. In typical standard applicaiions. dielectric considerations will detennine the enclosure dimensions. For high current rated circuits, thermal considerations may require larger dimensions to maintain temperatures within acceptable limits.
The GlL installation is gencrally defined by the transmission system or application requirements. The GIL is usually installed using different methods: in a tunnel, duct, or trench: on steel structures above ground or directly buried in the ground.
The aboveground installation is most commonly found in electrical switchyards, installed on steel structures above ground and/or in concrete trenches or walls. In a switchyard appliceation, the GlL connects the GIS with other remote equipment like transformers, overhead lines, or other sections of an existing substation. This application is also the most economical because minimal excavation is required for the structural supports. An aboveground installation can also be provided in public access areas: however, physical security should be considered, including fnces, climbing deterrents, and gas density monitor covers, etc.
Directly buried installations are used inside or outside substations where the (ilL is used to connect remote equipment or switchyards. In this case, the GIS is typically covered with a minimum of I m of soil and provided with cathodic (corrosion) protection. The cathodic protection that can be used is either a traditional system or a coating that is applied to the enclosure. If a concealed installation is required for either security or aesthetic purposes, a buried installation should also be considered. In any case, the GIL route should be carefully investigated for interferences above and below grade. Buried installation may also require a larger trench width “footprint” because the phases are usually arranged in a flat configuration.
A tunnel is widely used for underground installations in cities or other areas with limited space and obstacles along the route. These tunnels are either drilled very deeply. typically 20 m to 40 m below the surface, or close to the surface built using an open trench, and then backtilling to create a tunnel. A tunnel of 3 m in diameter is sufficient for incorporating a two-circuit GIL system. GIL tunnel installation is often fbund in conjunction with hydroelectric or pump storage power plants where the electric power generation is in a mountain cavern and the GIL is used to transmit the electrical energy to the transmission grid at the surface.IEEE C37.122.4 pdf download.
