ROBO INSPECTION IN TRANSMISSION LINE... |
Times sure have changed. robots used to be the only effective way to
inspect an overhead transmission line was by flying around in a helicopter with a pair of binoculars. But using choppers isn’t cheap when you’ve got thousands of kilometres of high-voltage equipment to watch. Faced with tight budgets and an aging workforce, utilities are increasingly experimenting with line-crawling robots as a safer, less expensive way to inspect their transmissioninfrastructure, much of it installed during the 1970s and showing its age. “There have been accidents over the years of people flying in helicopters, so the first issue here is safety,” says Andrew Phillips, director of power transmission studies at the Electric Power Research Institute. Phillips says the average industry worker’s age is 48 and many of the most skilled linemen are nearing retirement. “We just don’t have those people anymore.” He adds that robot line inspectors will help bridge the coming skills gap, improve worker safety and be less costly in the long run compared with conventional approaches to line inspection. “The expectation is that it will be at least less than 70 per cent of the cost.” It’s a trend that Hydro One — which has about 29,000 circuit kilometres of high-voltage transmission lines to monitor throughout Ontario — is closely following. “We’re definitely tracking the progress,” says George Juhn, director of investment planning and asset managing at the utility. “It looks like the future . . . but we’re not there yet.” Québec-Hydro is being proactive. It began researching robotic inspection devices after the 1998 ice storm, in which rain froze on transmission lines, adding weight that led to the collapse of lines and towers, leaving more than 4 million people in Quebec, Ontario and New Brunswick without electricity – many for several weeks. So the utility developed a small, remotely controlled robot called LineRover and in 2000 began using it as a way to de-ice live transmission wires. It worked well, and the LineRover evolved as more sensors and cameras were added, allowing it to perform more detailed inspections as well as spot trees and other vegetation that could short out lines. It was an overgrown tree, for example, that triggered the massive Northeast Blackout of 2003. “But the LineRover can’t cross obstacles,” says Montambault, referring to the robots’ inability to move past transmission towers and hop on and off different lines. So he and his research team developed a more advanced model, called LineScout, which has been used by Hydro-Québec since 2006 and B.C. Hydro since 2008. The battery-powered LineScout is waterproof, equipped with four cameras, packed with sensors that can detect problems such as corrosion, and capable of working in extreme temperatures. It hangs from the line like a mechanical sloth on roller skates, travelling at about four kilometres an hour. Each battery charge allows it to perform six or seven hours of work. “The main challenge was to develop this robotic platform to be reliable, cross obstacles and really reach almost any place on our circuit in harsh environments,” says Montambault. He said it used to be that lines were de-energized —disconnected temporarily from the grid – so workers could inspect them safely. But rising demand for electricity is making it more difficult to take lines out of service, requiring that work be done on live wires. “Now they can send the robot to do the live-line inspection, bring back high-quality images and data, then let an engineer on the ground decide if repairs are necessary,” he says. over at the Electric Power Research Institute, efforts are being made to develop an even more sophisticated robot, one that can be put up on a line and left alone for long periods with little human intervention.
Such a device would be autonomous and capable of charging itself, likely by harnessing ambient energy from the transmission lines themselves. The institute has already developed a 64-kilogram, two-metre prototype that is being tested for the first time at an outdoor lab. It is equipped with solar cells that provide a small amount of backup emergency power, can hunt for connections that may be faulty as a result of overheating and can detect electromagnetic noises in equipment that could suggest problems. All the data that’s collected, including high-quality digital images, can be transmitted in populated areas through cellphone signals or, in more remote areas, via satellite link to a central office. Robots that not only inspect but also repair faulty lines are also a “That would be the beginning of what we call intervention or manipulation tasks,” Montambault says. “It’s a challenge, because the robot has to be stable, precise and have enough dexterity.” It’s an area where we can shine, he adds dproudly. “Canada is truly a leader in this.”
