GridInnovative smart grid technology solves decades-old problematic power grid phenomenon

Published 8 January 2018

Picture a teeter-totter gently rocking back and forth, one side going up while the other goes down. When electricity travels long distances, it starts to behave in a similar fashion: 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. This phenomenon — called inter-area oscillations — can be a problem on hot summer days when the demand for power is high. Sandia National Laboratories and partners have demonstrated a control system that smooths out these oscillations using new smart grid technology. Sandia’s controls use real-time data to reduce inter-area oscillations on western grid.

Picture a teeter-totter gently rocking back and forth, one side going up while the other goes down. When electricity travels long distances, it starts to behave in a similar fashion: 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.

This phenomenon — called inter-area oscillations — can be a problem on hot summer days when the demand for power is high. As more power is transmitted, the amplitudes of the oscillations build and can become disruptive to the point of causing power outages. Until now, the only safe and effective way to prevent disruptive oscillations has been to reduce the amount of power sent through a transmission line.

Sandia National Laboratories says that Sandia Labs and Montana Tech University have demonstrated an R&D 100 award-winning control system that smooths out these oscillations using new smart grid technology in the western power grid. The new system allows utilities to push more electricity through transmission lines, leading to lower costs for utilities and consumers and greater stability for the grid.

How inter-area oscillations affect grid stability
“Most of the time these oscillations are well-behaved and not a problem — they are always there,” Sandia engineer David Schoenwald said. “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.”

In August 1996, such oscillations became so strong they effectively split apart the entire western electric power grid, isolating the Southwest from the Northwest. As a result, large-scale power outages affecting millions of people occurred in areas of Arizona, California, Colorado, Idaho, Oregon, Nevada, New Mexico, and Washington.