The Secret to HVDC Grids: ABB Unveils HVDC Circuit Breaker
High voltage direct currents could go from superhighways to resilient grids.
Katherine Tweed: November 9, 2012
ABB, which has been delivering power over high voltage direct current for more than 60 years, has solved an engineering puzzle that has been around as long as HVDC.
The power automation giant just announced that it has cracked the code on building circuit breakers for HVDC power lines. The development allows for extremely fast mechanics with power electronics. In this case, the enormous amounts of power that are moving over HVDC lines can be interrupted within five milliseconds.
Currently, HVDC lines are widely used to move power across huge distances, because DC is more efficient across long spans than alternating current. The technology is particularly key for renewable projects, such as offshore wind farms, which are often far from city centers where most of the power is used.
“This historical breakthrough will make it possible to build the grid of the future,” Joe Hogan, CEO of ABB, said in a statement. “Overlay DC grids will be able to interconnect countries and continents, balance loads and reinforce the existing AC transmission networks."
He noted that wind power from Scotland could come into mainland Europe, along with hydro from Norway and solar from the Mediterranean region and North Africa. “It's a very simple thought: to use the ultra-efficient transmission plus the advantages of a grid,” he said. “Until now, that wasn't possible because of the risk that you couldn't isolate any fault.”
The technology uses semiconductor switches on each side of a mechanical switch to isolate up to 1 gigawatt of power that might be flowing over an HVDC cable. “The challenge was to break this in a controlled way,” said Schmidt.
ABB wouldn't say just how long it had been working on this project, but the company spends about $1 billion annually on R&D, and Schmidt described this as a “flagship” project.