With a length of 1 400 kilometers, Yunnan - Guangdong was the first system in the world to transmit electricity at a DC voltage of +/- 800 kV, connecting the ten-gigawatt hydropower plant from Yunnan province (South west of China) to Guangdong province (South East of China) with a capacity of 5000 MW. Until then, the highest bipole voltage was +/- 600 kV and the highest capacity was 3150 MW.

The project involved major technical challenges and required from key manufacturers the development of new products, new characteristics and functionalities.
Sediver developed a 550 kN High Resistivity Toughened Glass insulator – ( a combination of the most advanced electric glass performance with the highest mechanical strength rating)  in order to meet the  specific needs of CSG (China Southern Power Grid) for this project.

In 2008, CSG chose the reliability of toughened glass insulator by placing an order on Sediver of 85% of the tension strings of this key project.