A Swedish researcher has developed a new method of employing lightning and other high voltage currents to benefit power companies. Normally considered disruptive to transmission lines and destructive to the power grid, these so-called natural transients could be used instead to monitor the wear and tear on power components.
“We can use these high voltages to obtain more information about the condition of components like transformers and bushings than through offline inspections,” Roya Nikjoo, a doctoral student at the Swedish Centre for Smart Grids and Energy Storage at the KTH Royal Institute of Technology, said. “It gives us a more systematic way of tracking the trends in how components’ conditions are affected by high voltages.”
According to Nikjoo, signals are created when lightning or power switches break an electrical circuit, interrupting the current or diverting it from one conductor to another, signals are created, and those signals are used as stimuli to obtain a response from the power components regarding their status.
As part of a project beginning in 2011, the KTH electrical engineering researcher equipped power components with sensors to measure the current of lightning or switching impulses with different frequencies as it passes through the component. Combining the resulting data yields a graphic representation of the system, similar to the way an image of a fetus is produced via an ultrasound.
“It’s like getting the fingerprint of the component,” Nikjoo explains. “As that fingerprint changes I can use it to identify the well-being of the component, and know if something is wrong.”
The new technique could be used as “preventative medicine,” she added, alerting power companies to components that need to be fixed or replaced before they cause damage to nearby equipment.
Recently, Nikjoo has been performing the tests using higher voltages that are more similar to what occurs in the field, as well as investigating other parameters that can affect the results, such as the cables’ coupling in the measurement circuit. She believes the new method will reduce the cost of power equipment maintenance while helping to stabilize the electricity supply to customers.
“This [technique] can make electricity more reliable in a smart grid,” she says. “Customers won’t need to worry about blackouts or losing money due to a shutdown.”
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