Researchers find flaws in wind power 

Researchers at N.C. State and Johns Hopkins University found that increasing the use of wind-generated energy can make a power grid more likely to suffer harmful disruptions and disturbances.

Aranya Chakrabortty, an assistant professor of electrical engineering at N.C. State and senior author of a paper describing the work, said it is now the federal government’s goal to obtain 20 percent of all electricity from renewable sources by 2020, and interest in installing new wind plans is increasing.

According to Chakrabortty, different kinds of disturbances, faults and disparities are going into the grid all the time. The power flowing through the lines on a power grid can be impaired by small oscillations, deviations from the norm, when these disturbances occur.

Controllers inside of the power generators can mitigate these problems. The efficiency and stability of the grid is threatened only when the internal controls are not strong enough to handle the disturbances.

Through a project that began in the fall of 2012, Chakrabortty and his fellow researchers found that power from wind generation can sometimes worsen these oscillations, due partially to the fact that producing power from wind is much different than producing it with traditional generators.

However, the study also proposed a solution.

“Our paper really pointed out that it is equally important to pay attention to where the wind farms are being placed.” Chakrabortty said. “What we found out is that if we install wind farms in certain specific locations, they can actually help us mitigate some of those poor performances or the after-effects of those disturbances.”

The next step in the research is to review the findings and work on a solution for the lack of feasible “good” wind farm locations, according to Chakrabortty.

Chakrabortty said even though the team now knows of the best places to have wind farms, sometimes it might not be possible to put them in the optimal locations because of geographical and environmental factors.

According to Souvik Chandra, a graduate student in electrical engineering who is working on the project with Chakrabortty, the team designed controllers for the wind farm, which can mitigate the power system oscillations, even when the wind farm is placed in a “wrong” location.

“What we did was say ‘okay go ahead and place a wind farm in any other location that may not be entirely favorable, but then lets design a control mechanism with which you can have the same response as the farm would at a favorable point, despite the farm not being in that specific location,’” Chankrabortty said.

At the moment, members of the team are mostly trying to answer specific questions regarding the design of the control mechanism, Chankrabortty said.

According to Chandra, they are also attempting to analytically show the effect of the wind penetration on power system oscillations.

Chandra said that their work is particularly important because wind energy is one of the fastest growing sources of renewable energy, and in the next decade the use of wind-generated power in the grid is going to grow considerably following a rapid increase in wind farm installations due to government mandates.