A control system that smooths out inter-area oscillations—a problem affecting power systems connected by relatively weak tie lines—has been successfully demonstrated by researchers from Sandia National Laboratories and Montana Tech University. The system that uses smart grid technology could allow utilities to push more power through transmission lines, possibly nixing the need for new transmission lines and help to stabilize the grid.

Electric power grids operate well below transmission capacity to avoid widespread outages due to inter-area oscillations, which occur when the standard frequency of 60 cycles per second increases on the utility side of the transmission line while the frequency on the customer side decreases, switching back and forth every second or two. “Most of the time these oscillations are well-behaved and not a problem—they are always there,” explained Sandia engineer David Schoenwald. “But at a moment when you are trying to push a large amount of power, like on a very hot day in the summer, these oscillations start to become less well behaved and can start to swing wildly.”…

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