Technology Review – ABB, the large power and automation company, has developed technology that could provide an efficient way to transmit power from widely distributed solar panels, wind turbines, and other sources of renewable energy. The new technology is a fast and efficient circuit breaker for high-voltage direct-current (DC) power lines, a device that has eluded technologists for 100 years. The breaker makes it possible to join high-voltage DC transmission lines to form a resilient power grid.
DC lines have long been used to transmit power across the North Sea, and from large hydroelectric dams to cities. But until ABB’s advance, it wasn’t safe to connect DC lines into a large-scale grid.
ABB’s circuit breaker changes that. Within five milliseconds it can stop the flow of a huge amount of power—equal to the entire output of a nuclear power plant, ABB says. The breakers could be used to nearly instantaneously reroute power in a DC grid around a problem, allowing the grid to keep functioning. “Ordinarily, if something goes wrong anywhere, all the power goes off,” says Claes Rytoft, ABB’s chief technology officer. “The breaker can cut out the faulty line and keep the rest healthy.”
ABB engineers test out high-voltage direct-current concepts at this test facility.
Researchers have been trying to develop high-voltage DC circuit breakers for a century. Mechanical switches alone didn’t work—they shut off power too slowly. Power electronics made of transistors that can switch on and off large amounts of power offered a possible solution, but they proved far too inefficient. ABB’s solution combines power electronics with a mechanical switch to create a hybrid system that’s both fast and efficient. The new circuit breaker could also be far less expensive than systems that use only transistors.
Power converter: This equipment, which converts electricity from AC to DC and vice versa, is key for high-voltage DC lines.
Subterranean power: This converter station is part of ABB’s HVDC Light technology, which is designed especially for underground and underwater cables.