Gas-insulated switchgear

Traditionally, switchgear used to be air-insulated, but in 1968 Siemens began shipping its first gas-insulated switchgear (GIS), designed to deliver greater reliability in power distribution systems. Gas insulation makes it possible to shorten the distance between voltage-carrying parts, thus allowing a more compact design. Compared to air-insulated installations, gas-insulated switchgear requires up to 70 percent less space. The high density of our metal-enclosed switchgear maximizes safety, minimizes emissions and makes the switchgear essentially maintenance-free. Other advantages include high reliability and fast assembly.

Compared to conventional, air-insulated switchgear, gas-insulated switchgear helps to achieve a smaller carbon footprint. Gas-insulated switchgear’s small physical footprint also means it can be installed directly in load centers like densely populated urban areas, effectively reducing distribution networks’ coverage requirements and attendant transmission losses. This helps to save energy.

Siemens has developed a range of components for implementing gas-insulated switchgear systems, including circuit breaker components and drives, current transformers, voltage transformers, surge arresters, and gas-to-air bushings. We’re the only producer globally to offer a comprehensive portfolio of products up to 800 kV AC and are currently developing energy-efficient products and components for 1,200 kV AC.

Gas-insulated transmission lines

In places where construction or environmental constraints prevent the installation of overhead power transmission lines, gas-insulated lines (GILs) are an economical and ecological alternative. Gas-insulated lines are laid in tunnels, in some case, above ground, but for the most part in the ground. Thanks to their encapsulated design, which protects them against external influences, GILs are a highly reliably technological solution. Their transmissions losses are up to 70 percent lower than those of overhead lines; they produce less warming in their surroundings; they cost much less to operate; and their simple, maintenance-free design ensures a long service life.