Transmission Technologies and Implementations: Building a Stronger, Smarter Power Grid in China

The state grid corporation of china has been deploying ultrahigh-voltage (UHV) ac technology on a large scale since launching its Strong and Smart Grid plan in 2009. China has 80% of its hydropower generation in the southwest and 76% of its coal generation in the northwest. However, more than 75% of the country's energy demand is distributed in the eastern and southern coastal areas. This geographical mismatch between supply and demand made it necessary to build UHV transmission networks: transmission technologies at voltage levels of 1,000 kV for ac and ±1,000 kV for dc. In this article, the development of UHV transmission-system technologies and projects is detailed, with a focus on the UHV ac transmission system..