State Grid, the Chinese state-run and the world’s largest electric utility, recently started a DC project where the DC voltage is 1100 kilovolts.
Running from Changji to Guquan, this DC project is the world’s longest ultra-high voltage line at 3293km, according to State Grid, and is also the world’s first 1100kV ultra-high voltage project. The line has a transmission capacity of 12 million kilowatts. Siemens, among others, is involved in the project; the German company made the transformers.
The purpose of this power line, which starts in the northwest region of Xinjiang, is to transport excess electricity in remote areas to densely populated areas where demand is higher. China is increasingly using ultra-high voltage technology to transport both AC and DC current over great distances; Due to this high voltage, there is relatively little loss during the transmission of the electric current.
This technology is not a luxury in China, as the majority of hydroelectric power plants that generate electricity are located in the west of the country. In addition, a lot of coal is located in northwestern China, while demand tends to increase in the densely populated east and south of the country. In Xinjiang, where the line begins, there are large-scale windmill and solar panel projects; here is a large surplus of energy.
The current project, also known as the ‘Power Silk Road’, can send 66 billion kWh annually to eastern China, meeting the electricity needs of 50 million households. The project cost 5.2 billion euros and construction started in January 2016.