The Jinping-Sunan transmission link commenced operation in December 2012. Image courtesy of Gao Zhixing.
The Jinping-Sunan transmission line traverses for 2,090km from central-western China to east China. Image courtesy of ENERGY CHINA.
The Jinping-Sunan transmission link was the second long-distance UHVDC transmission line to be built in China. Image courtesy of State Grid Corporation of China.

The Jinping-Sunan transmission link in China is a 2,090km-long ultra-high-voltage direct current (UHVDC) transmission line commissioned in 2012. It was the world’s first UHVDC line to cover a transmission distance exceeding 2,000km.

The 800kV transmission line is owned and operated by State Grid Corporation of China (SGCC).

It is capable of transmitting up to 7.2GW of electricity from the Guandi and Jinping hydroelectric power plants on the Yalong River in the Sichuan province in central-western China to the highly populated Jiangsu province on the east coast of China.

The £2.7bn ($3.5bn) transmission project commenced operation in December 2012.

Route and design details

The Jinping-Sunan UHVDC line originates at the Yulong AC to DC converter station near the Xichang city in Sichuan province and terminates at the Tongli DC to AC converter station in Suzhou city in the Jiangsu province.

The AC voltage at both ends of the line is 525kV.

The Jinping-Sunan transmission system runs for a total distance of 2,090km passing through eight Chinese provinces including Sichuan, Yunnan, Chongqing, Hunan, Hubei, Anhui, and Zhejiang, and Jiangsu.

Jinping-Sunan transmission project details

The Jinping-Sunan transmission line transmits electricity from the 2.4GW Guandi, 3.6GW Jinping-I, and the 4.8GW Jinping-II hydroelectric power plants as well as surplus hydropower generation in other plants in the Sichuan province to the industrialised coastal area of Jiangsu province in eastern China.

The long-distance power line is capable of delivering 36TWh of electricity annually from the less-populates central-western China to the industrialised and more populated eastern China.

The £2.7bn ($3.5bn) transmission project was approved by the Chinese government as a solution to the recurrent power shortage in east China in November 2008.

Key equipment contracts for the project were awarded in 2011 and construction works were started in the same year.

At the time of commissioning in December 2012, the Jinping-Sunan transmission line had the world’s largest transmission capacity, longest transmission distance, and highest voltage level.

It was the second long-distance UHVDC line to be designed and developed by SGCC after the 1,980km-long Xiangjiaba-Shanghai transmission line that started commercial operation in July 2010.

Contractors involved

ABB was awarded a contract worth £103m ($165m) to supply the 800kV transformers for both the converter stations for the Jinping-Sunan UHVDC transmission project in April 2011.

ABB was also awarded a separate contract worth £74m ($120m) to design, engineer and supply key equipment including A5000 UHVDC converter valves, the control, and protection system and DC yard equipment for both converter stations in the same month.

The system and key equipment for the project were designed by ABB in close cooperation with SGCC and other local Chinese partners.

The Jinping-Sunan transmission line was the second UHVDC project for ABB in China after the Xiangjiaba-Shanghai transmission project.

Long-distance power transmission in China

The Jinping-Sunan transmission line is the second long-distance UHVDC transmission project to transmit bulk electricity from China’s lesser populated western regions to east China, after the Xiangjiaba-Shanghai transmission line.

The latest such project in the country is the Changji-Guquan UHVDC transmission line, which was commissioned in December 2018.

It traverses for a total distance of 3,324km from north-western China to east China and is the world’s first transmission line operating at 1,100kV voltage.