ABB Power Grids in partnership with State Grid Corporation of China (SGCC) has built 1,000 kV gas-insulated lines (GIL) laid in the Sutong tunnel under the Yangtze River to enable transmission of clean energy from West to East China.

The Sutong tunnel is part of the larger Huainan-Nanjing-Shanghai UHV AC transmission link constructed by SGCC.

The engineering challenge involved laying the lines under the estuary of the Yangtze River, spanning a section of water which is 3.3 miles wide and 246 foot deep.

The Sutong project is the first in the world that adopts UHV GIL technology in a transmission tunnel.

Source: ABB