Wudongde Hydropower Station, the world's seventh-largest, began transmitting water power from Southwest to Southeast China with 800-kilovolt ultra-high voltage direct current (UHVDC) on July 31. 

It's a major project of China Southern Power Grid that passes through four regions – Yunnan, Guizhou and Guangdong provinces, and Guangxi Zhuang autonomous region, with a total length of 1,452 kilometers.

It will also offer power resources to the Guangdong-Hong Kong-Macao Greater Bay Area, thus helping promote its economic recovery.

The project, with a total investment of 24.26 billion yuan ($3.47 billion), kicked off in December 2018. And it's scheduled to complete in 2021.

"The fact that the world-leading project was put into operation in advance shows our UHVDC technology has significantly improved. The new transmission mode will also provide experiences for the power grid development in the world," Li Licheng, academician of the Chinese Academy of Engineering, told media.

Rao Hong, chief technical expert of China Southern Power Grid, said the system can improve stability, safety and flexibility of power grid, to further support the transmission of electricity from the west to the east of the country.