China's first 500kV direct current transmission line project, which connects Shanghai's Nanqiao converter station and the Gezhouba Dam in Hubei province, was put into operation on June 18.

Equipped with the world's first controllable line-commutated converter (CLCC), the project has been hailed as a demonstration of the nation's advanced capabilities in power transmission technologies. The CLCC will make Shanghai's power grid more reliable and stable, said officials.

Established in 1989, the Nanqiao converter station receives and transmits electricity generated by the Gezhouba Dam and is an important source of energy for Shanghai.

Due to its aging infrastructure, the State Grid Corporation of China, the nation's largest power provider and the parent company of the Nanqiao converter station, carried out a six-month upgrading of the facility's core equipment.

The highlight of this round of upgrading is the application of CLCC technology, which was completely developed by the State Grid Smart Grid Research Institute.

Known as the "heart" of a power transmission line, this new converter can efficiently convert the extra high voltage direct current from central and western China to alternating current transmission that is needed in eastern China.

"The equipment here at our station used to be all imported," said Xue Chuliang, head of Nanqiao converter station. "Now, they are all made domestically."

The successful implementation of CLCC technology will provide new solutions for clean energy transmissions to eastern and southern China, and significantly contribute to the nation's carbon peaking and carbon neutrality efforts, according to State Grid's Shanghai branch.

Wang Xin contributed to this story.