Since a massive power outage occurred on the European power grid last year, the work of WSU researchers has helped to unravel the mystery of why it occurred and how to prevent similar events in the future.
European regulators recently published a nearly 500-page report on the outage, attributing it to numerous and interacting factors. The report cited work from researchers in WSU’s School of Electrical Engineering and Computer Science regarding poorly understood frequency oscillations throughout the power grid that were part of the event. The work cited came from PhD students, Arash Nezam Sarmadi, Tianying “Lily” Wu, Yuan Zhi, and Salman Shiuab. All have since graduated.
“We have the best students, and it is really something to be proud of for WSU that this report, originating in Europe, cited publications from four of our students, and that these tools we developed are being used — both in real time and for offline analysis of complex events — for this Iberian blackout,” said Mani Venkatasubramanian, Boeing Distinguished Professor in Electrical Engineering who led the work.
It was a beautiful spring day last year when the European power grid began oscillating in frequency. Venkatasubramanian, director of WSU’s Energy Systems Innovation Center, who holds a joint appointment at Pacific Northwest National Laboratory, has worked with graduate students for decades to develop online monitoring tools to detect these harmful oscillations that cause fluctuations in power outputs in the power grid. The work was funded by the U.S. Department of Energy and by the Power Systems Engineering Research Center. He received a patent and started a company, Phasor Informatics LLC, that has licensed the technology. The software uses a suite of algorithms to assess oscillation problems in transmission systems and to notify operators when they occur.
Two five-minute oscillation events occurred that morning in Spain, and each time, power grid operators in Paris, France, received notifications from the software developed at WSU. The operators in Spain, in coordination with their counterparts in France, took actions to dampen them.
“The phenomenon that a forced oscillation resonated with the system mode was something that we had postulated in our papers, and we showed the theory on how that would affect the large power system,” said Venkatasubramanian. “So those were what caused the big oscillations that were seen between Spain and France and possibly other countries.”
As grid operators reacted, however, voltages on the power lines increased above acceptable limits, and power plants automatically disconnected in a cascading event. In less than two minutes around noon, about 60 million people across Spain and Portugal lost power in an outage that lasted 12 to 16 hours.
A new open-source tool developed at WSU helped Iberian blackout investigators uncover the likely source of the first oscillation that originated in Spain.
Using a new open-source tool developed at WSU that uses measurements with a slower reporting rate to detect faster oscillations, the Iberian blackout investigators helped uncover the likely source of the first oscillation that originated in Spain.
“That was exciting because we developed this tool just two years ago,” Venkatasubramanian said.
Oscillations remain a challenge for the power grid. The researchers have developed controls intended to dampen them, but they don’t fully understand why those actions don’t always work.
The U.S. has strict regulations and a more robust system than many other countries, but there have been oscillation events here, which are warnings for the system. In recent years, power grid operators have been planning for and seeing significant changes in the grid’s management. The cost of renewable energy production has dropped dramatically so that solar and wind power are now the cheapest and often the most attractive ways to produce electricity. Renewables provide variable amounts of energy during the day and are often distributed around a region instead of being centralized. At the same time, climate change, extreme weather events, and the growth of AI and data centers add to power grid challenges. Meanwhile, the system remains hampered by the lack of transmission support.
“Because of economic and societal issues, it’s very difficult to build new transmission lines in the U.S., and that is stressing the system more and more,” said Venkatasubramanian. “It is requiring us to become smart in how we use the existing resources to serve this growing demand.”
Venkatasubramanian’s group is developing open-source planning tools for modeling and analyzing the complexities and uncertainties that come about from the use of renewables and from extreme weather events.
“As we think about the future when we do have more renewables dominating the power generation, it is important that we pay attention to these control requirements,” he said. “We should periodically check to make sure that the controls don’t lead to oscillations. Even for us here in North America, we have to start taking these seriously and put in place the controls that we need to keep the system well-behaved going into the future.”
