Power sources in large countries like China are often located in remote regions away from cities. The flow of electricity need to cross several hundreds or even thousands of kilometers to reach the cities. The key to increase efficiency with minimum transmission losses is to use ultra-high-voltage power transmission such as 1,000 kilovolt (kV) over long distances.
Gas-insulated lines (GIL) filled with sulfur hexafluoride (SF6) insulation gas are the ideal solution to transmit power underground with minimum transmission losses. These are most useful when overhead lines and underground cables are not possible e.g. in tough and harsh terrains where ultra-high voltages and currents are required.
The Huainan-Nanjing-Shanghai UHV AC project that is being constructed by the State Grid Corporation of China (SGCC), is the first of twelve key transmission lines as part of China's air pollution control action plan made in 2013. Once completed, it is estimated to decrease coal consumption which is ex-pected to reduce 960,000 tons of sulfur dioxide (SOx) and 530,000 tons of nitrogen oxide (NOx) emissions annually.
As part of this project, ABB will design, supply and commission 1,000 kV GIL to be laid in the Sutong tunnel under the Yangtze River. The ultra-high-voltage GIL will be constructed and installed in challenging conditions that is 75 meters under the river within 5.7 kilometers of tunnels, the world's first project of its kind. ABB's solution provides the highest transmission capacity with minimum losses to help build up East China's ultra-high-voltage network to ensure energy security and support economic and social development.
"We are proud to provide first ultra-high-voltage GIL solution in China for this pioneering project", said Giandomenico Rivetti, Managing Director of ABB's High Voltage products business within the company's Power Grids division. "We are committed to enhancing customer value through innovation and our ultra-high-voltage technology will help China to transmit large amounts of electricity across the country while strengthening the power grid and reducing environmental impact".