The Xiangjiaba-Shanghai 800 kV UHVDC project, status and special aspects

This paper presents the current status of the 800 kV UHVDC technology and presents how experience and confidence gained at an 800 kV long term test station is being utilized in executing the 800 kV UHVDC long distance bulk power transmission Xiangjiaba Shanghai. As a first step in the R&D activity, a long term test circuit installation was built in order to provide final qualification for the newly developed 800 kV products and for boosting confidence in 800 kV HVDC technology. It was energized at 855 kV DC in November 2006 at STRI, Sweden. The experience gained during the test circuit operation was utilized during the realization of the equipment. The critical equipment, like converter transformers, wall bushings and thyristor valves have all successfully passed their type tests and installation is now complete. The converter stations passed Open Line test at 800kV DC in December 2009. In addition to the main circuit development mentioned above, a new control and protection platform known as DCC800 was developed to increase reliability/availability to levels appropriate for the enormous power transfer capability of a UHVDC project. A number of 800 kV HVDC projects have entered the execution stage in China. At the same time, many other 800 kV DC projects are under planning by several utilities in other parts of the world, like in India and Africa.