ABB's UHVDC transformer passes stringent tests

ABB has successfully tested the low- and high-voltage units of the powerful ultrahigh-voltage direct current (UHVDC) transformer in China. The ±1100 kV (1.1 million volts) UHVDC transformer, developed and manufactured in close collaboration with State Grid Corporation of China (SGCC), has successfully passed a series of type tests, paving the way for the implementation of the Changji-Guquan UHVDC link, which will transmit power from the Xinjiang region in the Northwest to Anhui province in eastern China.

Changji-Guquan will be capable of transporting 12,000 megawatts of electricity — the equivalent of 12 large power plants and 50% more than the ±800 kV UHVDC links currently in operation. Transmission distance will be extended from around 2000 km to over 3000 km, enabling the integration and transmission of remote renewables on a much larger scale.

When fully operational this UHVDC link will be able to feed eight 500 kV and two 1000 kV AC lines — delivering power equivalent to twice the average annual power consumption of Switzerland. ABB’s latest breakthrough also makes it possible to connect ±1100 kV DC with 750 kV UHVAC links for the first time. In addition to the transformer, ABB has also developed and successfully tested a range of other key ±1100 kV components, including converter valves, bushings and DC circuit breakers.

“In addition to transporting more power across longer distances with lower losses, this breakthrough will enable the interconnection of AC and DC grids and support the future linking of regions and countries,” said Claudio Facchin, president of ABB’s Power Grids division. “It reinforces our pioneering technology leadership in HVDC transmission and reaffirms our close collaboration with SGCC, as we enable a stronger, smarter and greener grid.

“The Changji-Guquan ±1100 kV project is a major technical step-up making it the world’s highest DC voltage. The transformer is a key element of this link and we are pleased that the first of these landmark transformers has passed critical tests and exceeded expectations. I would like to congratulate the teams from ABB and SGCC on this successful achievement,” said Liu ZeHong, executive vice president, SGCC.

China has major consumption centres in the east, while a significant amount of its energy resources are in the west and northwest. The expansive geography and increasing demand have prompted the build-up of ultrahigh-voltage links to increase transmission capacity while minimising losses.

Commenting on the impact of the technology breakthrough for Australia, Roland Vitelli, Power Grids Manager for ABB in Australia said, “With the capacity to deliver more power across longer distances with lower losses, this HVDC technology breakthrough will enable the interconnection of AC and DC grids and improve the economics of linking states and regions in Australia that previously would have been considered unfeasible.

“It can also help Australia in better matching supply and demand across the national energy network and utilise the diverse mix of energy generated across the different state borders to reduce costs and improve electricity reliability for residential and industrial users,” said Vitelli.