Photo: State Grid Corporation of China

Recently, the STATE GRID has started shield tunneling for the core section of the overland 220 kV cable line, boasting the longest-distance transmission in China. This pivotal part, known as the Green Expo Garden section of the Qiuteng-Wangjiang 220 kV project, will significantly enhance the power mutual aid capabilities on both sides of the Yangtze River in Nanjing upon completion.

The new cable line of the Nanjing Qiuteng-Wangjiang 220 kV project spans 27.91 kilometers. The 568-meter-long Green Expo Garden section, undergoing shield tunneling, serves as the core area for seamless connectivity along the entire line. Given a maximum burial depth of 14.7 meters in this section, a slurry shield machine with a 3.74-meter excavation diameter is being utilized. As the section is situated in a layer of muddy silty clay with high water content in the Yangtze River floodplain, the construction team has strategically employed an innovative "new socket-and-spigot segment" technology for constructing the power tunnel. This technology is able to improve the tunnel's deformation resistance and the force-bearing capacity of the annular structure, thereby significantly reducing the pressure of tunnel operation and maintenance at a later stage.

Photo: State Grid Corporation of China

The project is expected to be completed and put into operation before the summer peak this year. Upon completion, it will enable the direct transmission of green wind power from northern Jiangsu to the core region of Nanjing main city area, substantially boosting the power mutual aid capabilities along the Yangtze River banks in Nanjing. Notably, the maximum power supply capacity will be increased by approximately 1 million kW.