A story of mine published this week in MIT Technology Review takes a look at a new robotic device being designed by researchers at the Electric Power Research Institute, a non-profit research organization for the utility sector. Tens of thousands of kilometres of overhead transmission lines stretch across North American, bringing electricity from central power stations to population centres. The system we have is aging and in need of upgrade, while expansion is also on the horizon as states and provinces move to connect remotely located wind, solar and geothermal power sources. At the same time, past methods of inspecting the condition of transmission infrastructure is getting trickier. Many of the workers skilled in this area are nearing the age of retirement, threatening to create a skills gap in the coming years. It’s for this reason that robot inspectors are beginning to attract attention, with the idea being that one day we might have fleets of inspection robots moving along the nation’s power lines 365 days a year.

The folks at EPRI have designed one two-metre long prototype that looks kind of like a small solar-powered car — you know, like one of those high-tech solar cars you might see on the Discovery Channel. The robot, which is likely to be much smaller when commercialized, moves on rollers that clamp onto the shield line (there to attract lightning strikes) located just above the transmission lines. It crawls along the shield line at about 2 kilometres an hour. A high-definition camera snaps digital images of the surrounding infrastructure, making sure vegetation (trees) below isn’t interferring with lines and benchmarking the state of equipment and lines so they can be compared to future inspection runs. The robot will also have sensors that can detect electromagnetic interference, measure temperature of equipment and spot faulty line connections, among other things.

The data and images collected are transmitted back to a central office via satellite (in more remote areas) or cellular linkup. A lithium polymer battery powers the robot. In the picture above, it appears that the device is lined with solar cells, presumably to charge the battery. That was an older design. Andrew Phillips, head of transmission research at EPRI, said the latest prototype charges the battery by harvesting energy from the transmission lines below it. The transmission lines give off electromagnetic energy, and this is collected in the shield wire through induction. The robot taps into that power flow in the shield wire during the evening to recharge the battery. There’s still a small solar cell, however, for limited backup power.

So how are transmission lines currently inspected? Typically, crews are dispatched with helicopters that visually inspect vegetation and the basic condition of equipment, as well as collect data from sensors previously attached to transmission equipment. It costs a lot of money — both in helicopter and labour costs — to cover so many thousands of kilometres of infrastructure. EPRI figures that its robots can do the job at 70 per cent of the cost, collect better data, and do it without the safety risks that come with flying helicopters close to high-voltage wires.

Seems like a great use of technology — I can even envision these robots playing a grid security role as well, particularly as the electricity system becomes an even more strategic asset in an age of electric transportation.

This entry was posted on Thursday, June 10th, 2010 at 10:05 pm and is filed under grid, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.