This transformer bushing insulates the conductors that carry high-voltage current through a grounded enclosure, and is an essential component controlling electrical voltage, thermal current and mechanical stress. It had to demonstrate both low temperature increases to ensure safe, long-term operation, and reduced length to lower the costs of the HVDC valve hall design.
The new technology enables larger transmissions of clean power from remote renewable sources in countries like China, which is developing long-distance power infrastructure in order to reduce CO2 emissions by replacing urban-based coal-fired power generation.
More power than before
ABB's new bushing technology enables up to 25 percent higher power transmissions over distances exceeding 1,600 km, increasing the power capacity of ultrahigh-voltage direct current (UHVDC) long-distance transmission links to an unprecedented level. The extra power is equivalent to the output of 10 large-scale generation plants.
The first project for this new technology will be in China for State Grid Company of China (SGCC), China's state electrical utility.The 1,609 km-long Ximeng-Taizhou and 1,231 km-long Shanghaimiao-Shandong 800 kV transmission links will be able to deliver 25 percent more power from Inner Mongolia through the same narrow transmission corridor thanks to ABB's bushing technology. Creating long-distance transmission links to bring power to urban load centers eliminates the need to transport millions of tons of coal to distant generating sites.
Substantial emissions reductions
This project alone aims to reduce CO2 emissions by about one-third of a billion metric tons, reduce sulfur dioxide and mononitrogen oxide emissions, and eliminate about 140,000 metric tons of smoke and dust from the air.
ABB's new gas-insulated transformer bushing GGF800HC passed a type test for temperature increases at the Swedish Transmission Research Institute (STRI), which was witnessed by a high-level delegation from SGCC,. The type test requirement of 6,500 A (ampere) was substantially exceeded over many hours, demonstrating stable temperature throughout the required temperature range.
In addition to enabling higher power transmissions over longer distances, ABB's UHVDC bushing technology reduces transmission footprints because it requires fewer transmission towers. It provides low and stable temperature control at very high power levels, and is the shortest high-power bushing design available on the market.
UHVDC transmission is a development of high-voltage direct current (HVDC) transmission technology, which was pioneered by ABB more than 60 years ago and is now the preferred solution for transmitting large amounts of power over long distances to high consumption centers with minimal losses. Since its inception, ABB has been awarded about 100 HVDC projects, which represents a total installed capacity of more than 120,000 MW and accounts for around half the global installed base of HVDC systems.
