A new suite of software tools will allow the nation’s electrical grid managers to detect and track instabilities in real time.
Developed by engineers at the University of Wisconsin-Madison, Washington State University and Electric Power Group, these tools can help prevent common disruptions—down wires from storms, or a short in a piece of grid infrastructure, for example—from becoming major catastrophes.
When something goes wrong on the grid—the massive, interconnected networks of power plants, substations and wires that make up the electricity system in the United States—the disruption reverberates across the system. This “vibration” jolts the system’s normal operating frequency out of whack. Most of the time these vibrations self-correct; occasionally the oscillation amplifies and leads to catastrophic system failures. Grid operators need to detect and monitor these oscillations before they get out of hand.
“When something happens, the grid rings like a bell,” says Bernard Lesieutre, a professor of electrical and computer engineering at UW-Madison who led the effort. “The risk is, an event could happen where the system vibrates, but it gets bigger and bigger. That doesn’t happen too frequently. But it’s devastating when it does.”
Bernard Lesieutre
The danger is not theoretical. Major blackouts in 1996 in the western United States and a massive 2003 blackout in the Northeast and Midwest were both caused by persistent oscillations that weren’t recognized until it was too late.
Most grid operators can’t see these persistent oscillations in real time; they only know these disruptions have occurred by comparing data across various local points on the grid. Lesieutre’s software takes advantage of new GPS devices called synchrophasors recently added to many parts of the grid. These devices allow operators to measure voltages, currents, frequency and power. The software aligns the synchrophasors’ data from across the grid in real time, provides operators a snapshot of what’s happening, and allows them to detect persistent oscillations as they develop and to take action, if needed.
While GPS integration and time synchronization are ancient technologies for many industries, they are a recent upgrade for grid operators. “It’s an industry where things move very slowly; it’s not like the computer industry,” says Lesieutre. “It can take 20 years to implement new technologies. In part, we want to be careful with a technology our whole society relies on.”
He and his colleagues also developed a second piece of software that can detect “forced oscillations.” Caused by a malfunctioning or miscalibrated piece of equipment, these smaller, localized persistent oscillations can lead to later disruptions in the grid. Because the software can provide data at 30 frames per second, it can pinpoint the location of the problem equipment and the persistence of oscillations, which allows grid operators to find and fix or remove the problem.
In fact, Electric Power Group, a California-based software vendor for the power industry, already has incorporated that piece of software into some products it provides to grid operators. The online monitoring system for grid oscillations is currently in use at the Bonneville Power Administration synchrophasor laboratory in the Pacific Northwest and, Lesieutre says, may eventually make it to other grid control centers as well.
The researchers’ work was funded through a five-year U.S. Advanced Research Projects Agency-Energy grant.
Top photo via iStock.