Power grids have hidden threats such as tree limbs brushing wires that could spark outages or wildfires. With that in mind, researchers at the University of Texas at Austin have developed a sensor that clips onto live power lines with the goal of catching those threats.

The sensor alerts utility employees to a potential threat, enabling an immediate response. Without an intelligent power line sensor, if there is a tree-brushing event, the utility has to rely on luck or someone reporting visible smoke.

Researchers at UT’s Center for Electromechanics (CEM) have spent more than five years working on this project, combining edge computing, telecommunications, power harvesting and machine learning through field and laboratory tests to enhance electricity reliability and improve grid resilience.

“Power lines face many undetected threats, from tree limbs momentarily touching the power lines by the action of wind gusts, to aging grid components nearing permanent failure,” said Pablo Paz, CEM research associate and technical lead on the project. “It was rewarding to see the instrumentation perform exactly as designed and to witness the field results align with our laboratory tests.”

The sensor is comprised of two boxes that can easily be wrapped by a lineman onto a live power line, according to UT. They can measure activity along a line for miles.

The sensors are self-powered when a tiny fraction of the current flowing through the power line is inductively drawn in. The researchers said the intelligent sensor represents a significant advantage over conventional equipment, which needs auxiliary transformers and pole modifications, increasing installation complexity and cost.

Traditionally, after storms, utility inspectors drive through an assigned area looking for problems, which is a time-consuming and unsafe activity. Not only does the sensor spot faults such as a branch hitting a line but it can also pinpoint where incidents occur, helping utilities speed recovery.

“In the event of a windstorm, utility employees might have to drive dozens or even hundreds of miles to inspect power lines, and this is something they have to do anyway. If we can give them specific locations to inspect, it will greatly speed up the process,” said Shannon Strank, CEM’s deputy director.

The sensor recorded 34 events during one month of field testing last fall, compared with only three registered by legacy equipment. The grid can tell us much about its health, the researchers say, if people listen better.

When a tree contacts a power line, it is known as a high-impedance fault. In the past, because the cost of outages was low, these faults didn’t need to be addressed until the impact became detectable by conventional sensors.

Today, the stakes are higher. Infrastructure issues, higher power demands from new technology, and increasingly volatile weather motivated the researchers to improve measurement and grid systems, CEM said.