LEADING power and automation technology group ABB has successfully tested a new type of transformer that is a key component of power superhighways, or power links that can deliver vast amounts of electricity over very long distances.
UHVDC (ultra-high-voltage direct current) is a technological development of HVDC, which was pioneered by ABB more than 50 years ago, and is the biggest leap in capacity and efficiency of transmission in more than two decades.
Power transmission at ultra-high voltage has considerable advantages for the environment as it reduces power losses and requires a smaller transmission corridor than conventional technologies.
UHVDC technology is particularly suitable for large countries such as China, where the centres of power consumption are often far from the power sources. There is talk of using it in Europe to cut power transmission losses.
ABB developed its new 800-kilovolt (kV) transformer within one year of winning a major order to equip the UHVDC transmission corridor from the Xiangjiaba hydropower plant in western China to Shanghai, 1,250 miles to the east.
It is the world’s highest-voltage power link and will have a record capacity of 6,400 Megawatts, capable of supplying about 31million people.
The transformer is the first of several ordered by the State Grid Corporation of China (SGCC) and is a critical element of the systems that ABB is supplying to convert AC current to DC and back, and to alter the voltage at each end.
Among other challenges, raising the voltage to as much as 800kV increases the technical requirements on a transformer’s insulation and on the design of critical parts such as bushings.