GE Research reported that it was awarded $5.8 million in funding from the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) for a three-year project to develop and demonstrate a super-fast dc circuit breaker that is essential for enabling next-generation Medium Voltage Direct Current (MVDC) grids. This project is part of a broader concern of ARPA-E to upgrade existing ac distribution grids and expand the ability of to access remote clean energy sources in congested areas to meet future power needs.
“Many big urban cities today are facing higher electricity demands because of growing applications such as electric vehicle charging, with limited options for tapping into new energy sources,” said Timothy Sommerer, Principal Scientist at GE Research and Principal Investigator on the MVDC program. “By upgrading existing ac distributions grids to MVDC grids, it would allow these cities to cast a much wider net in securing new clean renewable energy sources.”
Sommerer continued, “The new super-fast ac circuit breaker we’re developing is an essential component for enabling the distribution grid upgrade from ac to MVDC. Because dc doesn’t inherently contain natural breaks like ac that help manage faults, you need to have a switch with an extremely fast response time that can create these breaks. That’s exactly the challenge GE’s technology will address.”
Sommerer explained that the team will leverage GE Research’s gas discharge tube technology to develop the MVDC circuit breaker. Gas discharge tubes switch without mechanical motion by transitioning the internal gas between its normal insulating state and highly conductive gas plasma. This transitioning enables much faster response times that are needed to handle dc currents.
The MVDC distribution lines envisioned are expected to support up to 100,000 Volts and more than 100 megaWatts of power to meet the needs of large cities. GE Research notes that the land area required to power a city with renewable sources such as wind, solar, and hydro is between 3 times and 10 times larger than the city itself and is usually some distance from the city. At the same time, demand for electricity in urban areas is increasing as vehicles and other fuel-burning power users go electric.
In general, the increasing use of dc in electricity transmission has the potential to greatly expand where utilities can draw power from to meet their energy needs in two critical ways. First, the company points out that electric power can move more efficiently over long distances on high-voltage dc lines compared to ac. Secondly, an MVDC distribution grid can then take that HVDC power and distribute it more efficiently and effectively into a large urban area.
The technology is expected to increase access to new clean power sources for congested cities where there is little or no room for the installation of new electrical distribution capacity. Furthermore, the development of MVDC systems could create new transmission and distribution markets for the grid industry.
“The development of dc grid technologies could vastly increase the flexibility utilities have in addressing future power needs,” Sommerer said. “Imagine the day when cities like New York, Chicago, or Los Angeles have the option of accessing electricity from multiple wind installations in the Midwest to meet electric vehicle charging needs.”