Siemens Energy and the utility China Southern Power Grid has put the first pole of an enormous HVDC system into operation. With a transmission capacity of 5000 MW und covering a distance of more than 1400 km, the implemented Yunnan-Guangdong high-voltage direct-current transmission system is the world’s most powerful of its kind, according to Siemens. At the same time, it is the first HVDC link operating at a transmission voltage of 800 kV.

Commissioning of the second pole and startup of the entire system are scheduled for mid-2010.

China has raised the DC voltage of its new long-distance HVDC links to 800 kV to further reduce transmission losses and to be able to bridge even greater distances. For example, the CO2-free power generated by several hydropower plants will be transported with low-loss transmission via the new 800-kV HVDC link to the rapidly growing industrial region in the Pearl River delta in Guangdong Province with its mega-cities Guangzhou and Shenzhen. This high-efficiency HVDC system can reduce annual CO2 emissions by more than 30 megatons, which would otherwise have been produced by additional fossil-fueled power plants linked to the interconnected grid in Guangdong Province.

Together with its Chinese partners, Siemens designed the entire HVDC system for the Yunnan-Guangdong project and supplied the core components, which included 800-kV and 600-kV converter transformers, DC filters and 800-kV direct-current components.