Pressurized air cables to reduce transmission losses in medium- and high-voltage grids

Pressurized air cables are coaxial tube arrangements which use pressurized air for insulation at medium- and high-voltage levels. They can replace overhead lines, traditional XLPE cables and SF6 gas-insulated lines. Key advantages of this new technology are a compact, boltless flange design, large conductor cross sections (> 2200 mm(2)), and fireproof metallic enclosures. The new flange design is key to use pressurized air for insulation as it allows large insulation gaps at the same flange diameter. The flanges are airtight and burstproof. A design option with flexible flange connections simplifies installation in non-straight arrangements and allows relative movement during earthquakes or ground settlement.Type tests according to IEC 62271-204 and test installations for medium voltage and high current (36 kV, 3000 A) as well as high voltage (145 kV, 2000 A) have confirmed the technical characteristics of pressurized air cables. Therefore, pressurized air cables support modernization and upgrade of the electric grid to be more efficient, more powerful and more sustainable.