Transforming China’s power

ABB has successfully tested a new type of high-voltage transformer for use in ‘power superhighways’ that transmit large amounts of electrical power over long distances.



The company developed the 800kV transformer for use in the world’s longest and highest-voltage power transmission link, located in China.


The 2,000km ultra-high-voltage direct current (UHVDC) transmission corridor will run from the Xiangjiaba hydropower plant in western China to Shanghai.


It will boast a capacity of 6,400MW, capable of supplying about 31 million people.



The transformer is the first of several ordered by the State Grid Corporation of China (SGCC), and forms part of ABB’s apparatus to change the current from AC to DC and raise the voltage for transmission, before dropping it back at the other end.


ABB said that the technical challenges of raising the voltage to as much as 800kV included additional demands on a transformer’s insulation and on the design of critical parts such as bushings.



Power transmission at ultra-high voltage reduces power losses and requires a smaller transmission corridor than conventional technologies.


UHVDC technology is particularly suitable for large countries such as China, where power generation facilities are often far from where output is used.