On June 11, the world's first ±500 kV three-terminal DC project - the Yunnan-Guizhou Interconnection Channel project of the Southern Power Grid was successfully completed, and the three-terminal bipolar project was put into operation at one time, 19 days ahead of the planned time, marking the formation of a power interconnection and mutual benefit complex between Yunnan and Guizhou provinces, which can transport Yunnan clean hydropower of about 6 billion KWH to the Guangdong-Hong Kong-Macao Greater Bay Area every year. It plays a very important role in promoting the consumption of clean hydropower in Yunnan and helping the construction of Guangdong-Hong Kong-Macao Greater Bay Area.

Project investment of 3.826 billion yuan, the construction of Yunnan Luquan converter station and a 389 km long DC line connecting with Gaozhao DC terminal high slope converter station, the transformation of Guizhou Gaopo converter station and Guangdong Zhaoqing converter station, forming Yunnan Luquan converter station - Guizhou Gaopo converter station - Guangdong Zhao The project for the first time in the world to transform two ends of DC into three ends of DC. The power transmission mode is more flexible and economical, which has practical significance in engineering for large-scale power transmission, multi-point decentralized access at the receiving end, optimization of power grid structure, and improvement of security and stability of the receiving end power grid. The project has overcome problems such as high altitude, heavy ice area, developed karst, and karst landform, and achieved a number of power grid technological breakthroughs such as multi-terminal DC flexible power supply and high-altitude DC equipment. The three-terminal DC control protection system, DC high-speed switch and other engineering key equipment are fully using domestic equipment, and the autonomy rate has reached 100%, which is an important milestone for China to master the multi-terminal DC key technology.