(Yicai Global) Dec. 22 -- Shanghai has begun operating the world's first more than one-kilometer-long 35-kilovolt superconducting power cable project, which should mark China's advance in the highly efficient electric transmission technology.

The 1.2-km-long demonstration project that is located in the eastern city's Xuhui district is global No. 1 in both distance and capacity, Shanghai Securities News reported today. The cable connects two 220 kV transformer substations with a current rating of 2,200 amperes and a mega-volt rating of 133.

Construction of the main part began in April 2020 after the project was first launched in 2016. The technology includes a liquid nitrogen cooling system to make sure a minimum amount of electricity is lost in the transmission process. Moreover, it has other advantages.

The power cable equals four to six conventional cables of the same voltage level and thus uses 70 percent less underground pipe space, said Xie Wei, an engineer working for the project's builder State Grid Shanghai Municipal Electric Power.

"Such an advantage makes the superconducting cable very suitable for application in the downtown urban area where an inch of land equals an inch of gold," Xie added.

Editor: Emmi Laine, XiaoYi