Robotic Crawlers Assess New Orleans
Power Lines Damaged By Katrina
Though undetected damage to power lines caused by hurricanes, landslides, wind storms and other calamities may not disrupt power transmission in the short term, they can become an ongoing cause of power outages if not found and fixed. Last month, scientists from the University of Washington tested “robotic crawlers” on power lines at a National Aeronautics and Space Administration facility in New Orleans to evaluate the robots’ capacity to detect damage to power cables. The crawlers are robots that propel themselves along miles of cable, conducting a check-up of the power lines.
“This is the first robot built that can inspect power cables autonomously, looking for incipient failures. It can find cables that may need repair, before they cause problems,” says Dr. Alexander Mamishev, an associate professor of electrical engineering at UW.
Mamishev directs the university’s Sensors, Energy and Automation Laboratory, which develops robots and network sensors to monitor infrastructure such as power cables, roads and bridges.
Although the prototype robot had been developed over the past five years and tested on underground power lines on UW’s campus, New Orleans was chosen for the field test because of the widespread damage to the city’s power system after Hurricane Katrina. More than a year after the storm, researchers say conditions in the city remain unsafe around power lines.
UW’s robots pinpoint problem spots by using information from the surface of a cable to assess its internal condition. Each robot — which resembles an insect and can negotiate tight curves — moves along the insulated distribution cable scanning for internal damage. It uses three sensors: a heat sensor that detects heat dissipation; an acoustic sensor that listens for partial electrical discharge; and a sensor created by Mamishev that detects “water trees,” pools of water that have seeped into the insulation. Engineers can monitor the robot through a wireless communication connection and view the robot’s environment through a front-mounted video camera.
“Right now, power companies either let a cable age until it fails or they take out the entire line after a set time period,” says Luke Kearney, an electrical engineering undergraduate student working on the project. “Knowing whether the cable is starting to wear would save power companies a lot of money, and it would reduce the number of blackouts.”
UW officials say that while some hand-held power cable sensors are now available, the power industry largely relies upon sending a person to monitor miles of cable by hand, a practice that is considered tedious, costly and sometimes impractical.
“Maintaining a distributed infrastructure — power systems, roads, bridges, tunnels, buildings — is a very large and costly endeavor,” Mamishev says. “Over the years, maintenance costs more than construction. Our vision is that someday robots will accomplish the lion’s share of maintenance tasks.”
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