The Little Robot That Could

PG&E has won plaudits for industry leadership in evaluating new “Smart Grid” technology to help operate its electric system more affordably, reliably and sustainably.

But behind the scenes, the utility is also testing some much less hyped, but no less important, new technology that may help it maintain the electric grid more affordably and reliably.

The backbone of PG&E’s electric grid consists of nearly 18,000 miles of high-voltage transmission lines, which carry enormous amounts of power from central generating stations out to distribution substations in the communities it serves.

An outage on a major transmission line can affect service to thousands of customers. Worse yet, a physical line failure can spark wildfires that destroy natural and inhabited areas.

Yet utilities operate largely in the dark when it comes to predicting and preventing transmission line failures. That’s because corrosion can weaken lines invisibly, leaving no obvious clues for line patrols to spot.

That process can take years or many decades depending on environmental factors. Salty coastal air, or acid rain from industrial pollution, can accelerate corrosion.

Since utilities can’t predict how long lines will last, they must either wait until the lines fail—at the expense of reliability and public safety—or replace them on some kind of schedule. The latter practice may replace lines long before they need to be, driving up costs to customers.

Fortunately, some dramatic new technology promises to give utilities the equivalent of x-ray vision. PG&E has been testing a robotic device called the LineVue™ tool, which rolls merrily along transmission lines. A magnetic sensor detects how much steel is left inside the conductor core. By plotting changes over time, utilities can predict when the line will weaken to the point where it needs replacement.

A Canadian company called Kinectrics developed the corrosion-detecting technology from an earlier application in the mining industry, where miners can die if steel hoisting cables break, said Craig Pon, the product manager for LineVue™.

PG&E tested the tool first in the lab and then on a transmission line near the town of Quincy in Northern California. “It passed with flying colors,” said Feven Mihretu, a transmission line engineer with PG&E. “It was amazing.”

Kinectrics is still field-testing and perfecting the technology, so it’s not yet in widespread use at PG&E or elsewhere. Meanwhile, Canada’s Hydro-Québec Research Institute is perfecting another inspection robot called the LineScout, which is heavier but works on a wider variety of line types. PG&E plans to test it soon as well, with the hope of deploying one or both tools sometime next year.

Comments are closed.

"PG&E" refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation.
© 2011 Pacific Gas and Electric Company. All rights reserved.