The increased interest in recent years for transporting clean and renewable energy from remote hydro generation plants has also increased the interest in higher DC transmission voltage than presently used (i.e. 600 kV DC). This has led to development of Ultra High Voltage Direct Current (UHVDC) at 800 kV DC.
800 kV Ultra High Voltage Direct Current (UHVDC) transmissions are economically attractive for bulk power transmissions of 5,000 – 8,000 MW over 1,000 – 1,500 km or above. 800 kV HVDC transmission projects are already in execution phase, and 800 kV is now an established voltage level for bulk power transmission over long distances.
ABB started with the development for 800 kV equipment to make this voltage increase possible. ABB also planned for a long time test circuit installation to establish a confidence in this new voltage level. The long term test circuit installation has been energized at 855 kV since November 2006 at the STRI Laboratory in Sweden. It has well served its purpose in providing final qualification for the newly developed products and boosting confidence in 800 kV HVDC technology with several utilities around the world.
ABB was awarded the converter equipment for the Xianjiaba - Shanghai ±800 kV HVDC Transmission project rated for 6,400 MW to transmit power over a distance of over 2,000 km by State Grid Corporation of China in December 2007. The project was completed inJuly 2010, one year ahead of schedule.
ABB has been selected by Powergrid Corporation of India Ltd. to deliver the world’s first multi-terminal ±800 kV UHVDC transmission link. The link is known as North East - Agra HVDC. The link comprises four terminals located at three converter stations with a 33% continuous overload rating and the power transmission system will thus have the possibility to convert 8,000 MW – which is the largest HVDC transmission ever built.